Light on the Earth

EIA of Geothermal Projects in Iceland

2011-12-24T09:32:00.007-10:00

Posted with permission from the Authors.

Proceedings World Geothermal Congress 2010

Bali, Indonesia, 25-29 April 2010

Environmental Impact Assessment of Geothermal Projects in Iceland

Albert Albertsson, Asbjorn Blondal, Bjorn H. Barkarson, Sigridur Dr. Jonsdottir and Stefan Gunnar Thors

HS Orka Ltd., Brekkustig 36, 260 Reykjanesbaer, Iceland. VSO Consulting, Borgartuni 20, 105 Reykjavik, Iceland

albert@hs.is, asbjorn@hs.is, bjornh@vso.is, sigridurj@vso.is, stefan@vso.is Keywords: Environmental impact assessment, consultation, geothermal power plants.

ABSTRACT

There are some fundamental differences between energy projects in Iceland which have consequences for the efficiency and function of the EIA process. Most of the hydropower projects are well defined projects, i.e., the design, size and magnitude of the project is known when assessing the impact of the project. The characteristics of geothermal utilization can be very different. The utilization of geothermal energy is dynamic in nature, where the information is being gathered and processed continuously during the time of utilization. The paper discusses how the EIA Act and EIA process in Iceland function for geothermal projects and if it should be more flexible for such dynamic projects. The paper reviews geothermal projects, describing the main benefits and problems relating to the EIA process as well as the process of applying for consents and permits under various acts. The paper discusses possible solutions to the problems accounted for example using tools of planning, allowing more flexibility in the EIA, implementing more consultation among interest parties and agencies, and using area approach instead of structural approach.

1. INTRODUCTION

Since the year 1993, the legislation and the process concerning environmental impact assessment (EIA) in Iceland, have been evolving. During this period, much emphasis has been on projects like hydropower plants and roads. The last few years more emphasis on geothermal development has cast a new light on the EIA process its purpose. Some points have proven positive and some have raised questions about whether the current process suits projects with dynamic nature like in the geothermal exploration and development. The purpose of this paper is to give some insight into the Icelandic EIA process and how it has been employed in the geothermal field.

2. THE BACKGROUND OF ENVIRONMENTAL

IMPACT ASSESSMENT (EIA) IN ICELAND

In the year 1993 the Icelandic government legalized the EU Directive number 85/337/EBE with the Environmental Impact Assessment Act no. 63/1993 (EIAA). In the year 2000 a new EU directive (Directive 97/11/EB) came into effect and changes in the Icelandic EIAA followed. In the year 2005 the EIAA was changed once again but this time exclusively on the initiative of the Icelandic government.

2.1 The Environmental Impact Assessment Act and the

EIA Process

2.1.1 Geothermal Projects Subject to Assessment

Geothermal power stations and other thermal power installations with a heat output of 50 MW or more and other power producing units with an output of 10 MWe or more are always subject to an EIA.

In the year 2000 a more fundamental screening process was implied as part of the EIAA. Projects which may have substantial impacts on the environment are assessed on a case-by-case basis, regarding the nature, size and location to determine whether they shall be subject to an environmental impact assessment. For geothermal projects that fit into that category are deep drilling, in particular drilling of production wells and exploration wells in hightemperature geothermal regions.

In addition projects which are subject to an environmental impact assessment and are planned in the same area or are contingent upon one another may be assessed jointly, e.g. geothermal power station subject to assessment and the adjacent power lines.

2.1.2 Scoping Document

If a project is subject to an impact assessment the developer shall submit a scoping document. A scoping document contains a description of the project, the project site and alternatives which could be considered. The scoping document also proposes which aspects of the project and of the environment will be illustrated and what data will be gathered.

2.1.3 Initial Environmental Impact Statement (IEIS)

Following a scoping document the developer publishes a report on the project’s environmental impact assessment. This report, the initial environmental impact statement, has to be consistent with the scoping document.

In the IEIS the project’s possible environmental impacts, cumulative and synergic, direct and indirect are discussed.

2.1.4 Environmental Impact Statement (EIS)

An Environmental impact statement is the final report of the environmental impact assessment for a project. The statement is based on the IEIS and the consultation, opinions and comments from governmental agencies, municipalities and the public.

2.1.5 Review

All the previous steps are subject to review by the public,

public agencies and authorities. Within four weeks of

receiving the environmental impact statement, the National

Planning Agency (NPA) shall deliver a reasoned opinion on

whether the report meets the criteria of the EIAA and

whether the environmental impact is satisfactorily

described. The NPA’s opinion shall explain the main

premises of the assessment, including the quality of the data on which the assessment is based and its conclusions.

Figure 1: Number of geothermal development projects in Iceland assessed case-by-case whether they were subject to EIA 2000-2008.

2.2 Geothermal projects in Iceland and EIA

For the period 2000 to 2008, 29 geothermal development projects were assessed case-by-case whether they were subject to an EIA (Error! Reference source not found.).

Six of these projects were subject to an EIA of which five

were exploration drillings and one was due to changes in

current project development. The projects are all situated in

high temperature areas, on the southwest coast,

Reykjanesskagi and Hellisheiði, and on the northeast coast,

Krafla and Þeistareykir. One project of these 29 was

situated in low temperature area.From the year 1994 to

2008, 14 geothermal projects were subject to an EIA and

most of them during the last eight years. The first Icelandic

EIA undertaken for a geothermal project dealt with

exploration drilling. Some of the EIA cases are for one and

the same geothermal development project, due to

enlargement of an existing power plant or additional

drilling of production wells or reinjection wells. Since the year 2000 geothermal projects are 13% of the total EIA cases in Iceland.

3. THE APPLICATION PROCESS FOR

GEOTHERMAL PROJECTS IN ICELAND

For geothermal projects it is necessary to apply for various permits. The number of permits varies with the nature of the project, e.g. whether permits are applied for a power plant of some kind or for drilling production or exploration wells. Table 1 displays an overview of the application process for geothermal projects in Iceland, which permits are applied for and what legal body issues these permits. The process also includes changes in land use plans in the given area. The developer is responsible for applying for these permits.

4. THE NATURE OF GEOTHERMAL PROJECTS

Geothermal projects are different from most other projects that have to comply with the EIA act. Whereas for example hydropower plants can in a way been looked at as a static projects the geothermal projects are of a dynamic nature.

This is due to:

· Difficulties in long term and even short term

projection of the reservoir behavior

· Reinjection schemes, depending on a number of variables not known in the beginning of the exploration phase

· The exact location of facilities not exactly known and to a great extent depending on drilling results

· Number of drilling pads needed depending on the nature and evolution of the reservoir

· What impact earthquakes can have on the reservoir data not known

· Possible modifications of the steam/brine system and the power plant needed in case of steam cap development and/or effects of earth quakes

· Possible changes with time of the chemistry of the geothermal fluid

The information gathered in the exploration phase can have a significant effect on the size, location and the overall design of the project. Hence, the geothermal projects are dynamic not static as many other EIA projects such as hydropower projects, roads and aluminum smelters. Due to this, some have questioned whether the EIA process in Iceland takes into consideration this fundamental difference of the geothermal projects.

The time of preparation, exploration, research and engineering design of geothermal power plants is longer than for most other EIA projects. This is mainly due to the nature of the geothermal resource. Today it is common in Iceland that it takes 10 to 13 years to develop a geothermal green field project.

Due to the nature of the geothermal resource, the outcome of the different surveys undertaken at a very early stage of the project and which is the basic data for the EIA is just indicative for the real, short and long term impact the project imposes on the environment. The cost of the preparation and research is known to be considerable.

Geothermal developments need rather extensive exploration area as well as rather large area for production wells, reinjection wells and associated facilities. Today the tendency is to minimize the impact area as much as possible. This has in some cases led to very unfavorable and difficult operation of the geothermal field.

Table 1: Permits and Processes for Geothermal Projects in Iceland.

Geothermal projects are preferably developed in steps. The overall experience gained from the operation of a preceding step is the basis for the design of the succeeding step. In this way the evolvement with time of the geothermal reservoir and the technology is coped with. A succeeding step to one or several steps in operation can for example be increased steam production with associated increased reinjection for power generation or other industrial usage which in turn calls for more wells to be drilled and more facilities to be built. The very nature of geothermal projects is therefore dynamic in the sense that they are continuously evolving during the entire life span of the resource harnessed. In many cases these steps are also subject to an EIA.

5. ENVIRONMENTAL IMPACT OF GEOTHERMAL

PROJECTS

Environmental impact resulting from geothermal development varies during the different phases of development and between sites. Kristmannsdóttir and Ármannsson (2003) have listed the main environmental issues involved in geothermal development:

· Surface disturbances

· Physical effects of fluid withdrawal

· Noise

· Thermal effects

· Chemical pollution

· Biological effects

· Protection of natural features

Geothermal exploration usually occurs in pristine areas characterized by volcanic activity, geothermal surface activity and geological formations. Ecosystems, both flora and fauna, are adapted to warm soils. Development includes roads, well pads and drilling of geothermal wells and groundwater and/or sea water wells. There is also deposition of waste soil and drill fluid including drill cuttings and mud. During flow testing of wells, steam and spray has shown to have temporarily adverse effect on the local vegetation with moss and grass being scalded. Noise follows flow testing of wells and can have negative effect on wildlife, tourists and local people.

If results from exploration are positive, development may continue. This can include more roads, well pads, pipelines, power plant, associated buildings and transmission lines. Geothermal power generation usually causes air pollution due to the emission geothermal gas from brine flashing, particularly carbon dioxide (CO2) and hydrogen sulfide (H2S), carbon dioxide adding to the greenhouse gas effect and hydrogen sulfide being poisonous in high concentration.

Gas concentration in emission varies to a great extent from one geothermal site to another. During operation, subsidence and induced seismicity are possible effects as is change in geothermal surface activity. Discharge of hot water and/or geothermal fluid from geothermal power generation can cause problems whereas the fluid can contain high concentration of various chemicals which may cause threat to living organs.

6. EXPERIENCE OF THE EIA FOR GEOTHERMAL

PROJECTS IN ICELAND

A few key issues should be noted from the brief history of EIA for geothermal projects in Iceland. This concerns the nature of geothermal projects, consultation in the EIA process, information and data concerning the key environmental factors affected by geothermal development and different vested interests in the geothermal development sites.

6.1 Consultation

6.1.1 Consultation Bodies

The EIA process for geothermal projects involves consultation with public agencies, local and governmental authorities, Non Governmental Organizations (NGO’s) and other stakeholders. By consulting with bodies involved in the EIA process at the early stages of each project, different views emerge which can be discussed and resolved before the project is fully developed.

In geothermal projects the Environment Agency, the National Energy Authority, local authorities, local Health Inspectorates, NGO’s and the Icelandic travel industry are considered as necessary consultation bodies. The National Planning Agency however plays a key role in the overall EIA process and should be consulted on regular basis.

6.1.2 Consultation during Scoping

Scoping document should be prepared in close consultation with the above mentioned parties. This is to ensure that all available data is included and that necessary research is planned for. Not doing so can cause delay and increase the cost of the project whereas research is time consuming and, in some instances, can only take place at a specific point in time of the year. This applies especially to ecological research. During preparation of scoping document meetings should be held where maps are presented and preliminary information regarding the project development is introduced, including energy output and input, effluent treatment, construction plans and available information on the development area.

Experience reveals that consultation does not need to be formal. Meetings can be informal but minutes of meetings are essential. These meetings can open up potential moments for deliberation. Matters discussed at consultation meetings should be addressed in the environmental impact statement.

6.1.3 Consultation for Environmental Impact Statement After reviewing research and exploration results and other

gathered data for a geothermal site, meetings with

consultation bodies should be arranged as often as

considered necessary. This allows for deliberation

concerning development of the overall project and

probable effects on the environment. This working

procedure usually raises questions at a point in time

in the development process when it is still possible

to make adjustments and plan for mitigation measures.

Developers and consultation parties do not always agree on what to emphasize on in the EIA but it is very important to address all those points at an early stage. The purpose of the EIA process is not halting the development of a project but to help public officials and the developer to make informed decisions that are based on an understanding of environmental consequences and take proper action before necessary permits are granted.

6.1.4 Consultation and Participation The main objective of public participation in the EIA process is that different views emerge and that all

stakeholders are involved in the decision-making. This does not necessarily lead to decisions that are beneficial for the environment but can help reaching reconciliation.

Public participation in the EIA process is developing in Iceland as well as elsewhere (Isaksson, 2009). A detailed framework does not exist on how this is best accomplished. Two geothermal EIA cases in Iceland show great disparity in public participation and interest.

The first case is the development of a new 135 MWe geothermal power plant in Hellisheidi area in year 2007. The proposed development is located in a scenic area with much geothermal activity on the surface. Gas emissions may cause negative impact on air quality and debate is on whether the harnessing can be considered sustainable. The EIA process sparked a lively discussion about the project. During the development of the environmental impact statement (EIS), a total of 675 individuals commented on the content of the document or the process of which 564 were unanimous. In addition a number of news articles were published.

In contrast during the EIA process for an 80-100 MWe enlargement of an existing geothermal power plant in Reykjanes in year 2009 no comment was given by the general public on the proposed project. This development was also intended in a scenic area with much geothermal surface activity, popular as tourist destination.

The reviewing process for both cases revealed a number of remarks from public agencies, local and governmental authorities including serious comments from the National Energy Authority.

The reason for this huge difference in public involvement is not clear but something sparked the interest in one case but not the other. It remains unclear whether many comments from the public deliver better grounds for making decisions concerning individual projects. Additionally, it can be questioned whether the EIA process is the right venue for such extensive paperwork. On the other hand, some have argued that the Icelandic public is prevented from influencing decisions regarding big projects which may affect the quality of their lives.

This experience gives reason and basis for development of a framework for public participation in the Icelandic EIA process. Its purpose should be a smooth development pathway, not to halt but to streamline a project. This framework could also take into consideration the different nature of projects.

The yes or no answer to a geothermal development question should be answered in a master plan, on national or regional basis and through strategic environmental assessment process (SEA). Land use policy should not be the challenge for the developers of individual projects.

6.2 Information

The issuing of geothermal research exploration permits and utilization permits must be based on reliable and detailed information about the projected impact the proposed project may have on the environment (Goff, 2000).

6.2.1 Geothermal Data and Sustainability

The management of geothermal energy as a natural resource is a vital issue in the EIA process. The assessment of sustainable use is a difficult task and controversy is among scientists, government agencies and developers how this is best accomplished. The conventional approach for the operation of a geothermal power plant is to increase steam production in steps while monitoring the effects on the reservoir. Developers’ point of view may be that in order to find out the long term capacity, fluid dynamics and thermodynamics of the reservoir it is necessary to tap the reservoir to such an extent and for a long enough period of time in order to get reliable response of reservoir variables for adjusting the reservoir model. Whereas this exercise is based on actual field trials for a long period of time with, in a way unforeseen results and uncertainty, it raises the question how to define a sustainable harnessing of the reservoir. Government officials, issuing permits, need to base their decisions on data at a very early stage of the project. They are responsible for the criteria for sustainable resource management. Presented with data, that shows pressure decline in the geothermal reservoir and pressure rise in the upper part of the system i.e. development of a steam cap, have created debate between parties on how and if to harness the geothermal reservoir.

In the EIA process for geothermal projects, this debate has become a larger part of the EIA deliberation. The knowledge and expertise of the nature and utilization of geothermal fields is limited to few professionals but the EIA process is intended to give the public the opportunity to follow this discussion. Everyone can reveal their opinion on this issue during the EIA process but only few scientists have the grounds to build their opinion on. Therefore, the scientific data, presented in the EIA and the debate between the geothermal specialists, may cause difficulty for public officials to understand and to make an informed decision. This makes the point that for the purpose of public participation in the EIA process, data must be presented in a clear and simple way. But this may be difficult due to the dynamic and unpredictable nature of the geothermal reservoir, as noted in chapter 3.

Therefore, the dialogue on whether the proposed resource harnessing can be considered sustainable, can only reach a certain point in the EIA process. The decision on whether a utilization permit or a harnessing permit is granted is not based on the EIA process but is the result of the communication of the developer and the Ministry of industry, energy and tourism / National Energy Authority (table 1). A development permit however is based on the EIA and the land use planning.

6.2.2 Geological Formations

Geological formations have been a key environmental factor

in the Icelandic EIA’s for geothermal projects. This is due to

the fact that geothermal activity is commonly associated

with volcanic activity, which is the source or origin of

geological formations. Many of these formations are

protected by the Nature Conservation Act, as landscapes

and ecosystems. This applies to volcanic craters, pseudo

craters and lava fields, as well as surface geothermal deposits

(sinter and travertine), 100 m2 or more in area.

Most geothermal developments influence to a certain degree the countenance of the landscape, i.e. the broad appearance of the landscape changes due to the alien facilities installed. Roads, production well heads, surface pipelines and buildings are examples of these aliens in nature.

Thanks to a technical development, the directional drilled wells have increased the flexibility in site selection for drilling. During the EIA process, this enables discussions between developers and geoscientists about the optimum locations and optimum numbers of well pads with associated service roads in order to minimize the environmental impact of the project.

Harnessing geothermal reservoirs causing pressure decline can change geothermal activity on the surface, causing geysers and hot springs to disappear or be transformed into fumaroles (Kristmannsdóttir and Ármannsson, 2003). This man made impact can be hard to distinguish from natural changes and can also happen in the course of seismicity. In the EIA it has been classified as indirect effect and is subject to great uncertainty.

This indirect impact due to tapping geothermal fluid out of the reservoir has called for development of mitigation measures like reinjection of geothermal fluid, establishing controlled and balanced harnessing of on the one hand the fluid dominated reservoir and on the other hand the steam cap once it is developed and proper monitoring of surface activity.

6.2.3 Geothermal Ecosystems

Ecosystems in geothermal areas are different from the surrounding ecosystems. These ecosystems can be considered unique in terms of biological diversity. They contain rare species of plants and moss, the microbial life in hot springs is very diverse and this also applies to the invertebrate species. Warm creek, originating from a hot spring, is different habitat than a cold creek close by. Consequently it also has different species composition. Geothermal development usually does not cause direct disturbance in these ecosystems. Directional drilling has also allowed for the protection of both fragile ecosystems as for rare geological formations. Nevertheless, the indirect effect on hot springs that may be caused by the geothermal harnessing, may lead to changes in these ecosystems. In recent EIA processes much attention has been given to this derivative impact on geothermal ecosystems. It can be argued that due to great uncertainty in predicting the effect of geothermal operations on hot springs this should not be given much weight in the EIA. On the other hand, these ecosystems are very susceptible and can be considered very important as components in Earths’ biodiversity.

It is also worth mentioning that the thermo files can be a valuable resource for the bio industry like the blue green algae, cultivated at the Blue Lagoon.

6.2.4 Tourism and Recreation

As mentioned above, geothermal exploration usually takes place in pristine areas characterized by volcanic activity. Many of these sites are categorized as of natural interest according to the Act of Nature Conservation and are popular as tourist destinations. Areas with good prospects for geothermal development are commonly popular as tourist destinations (Noorollahi and Yousefi, 2003). This has to some extent placed the tourist industry and the energy industry on opposite sides. The tourist industry claiming, geothermal development, including noise, surface disturbances and pipelines, will cause negative impact in popular tourist destinations. The geothermal developers on the other hand claiming the effect above ground occupying relatively confined area will be minor and that the tourist industry can´t claim any land use rights in these areas. The developers argue that gained experience proofs that visitor centers with educating exhibitions of the power plants and professionally guided tours attract every year thousands of visitors and therefore the geothermal installations can support the tourist industry.

Through consultation and problem solving some of these disputes can be resolved in the EIA process. This has been done through mitigation measures like minimizing visibility of buildings and pipelines, placing well pads far away from hiking trails, drilling many holes from each well pad and improving tourist facilities and hiking trails.

Opinion poll conducted in the Reykjanes area in Iceland has revealed positive view among tourists and recreational people towards geothermal power plants (Guðmundsson, 2008). When asked about steam released from a geothermal power plant the response was also positive. On the other hand, when asked about well sites and pipelines, the view was rather negative.

Kristmannsdóttir and Ármannsson (2003) also point out that there are not only negative effects of geothermal utilization to tourism. One of the most striking examples is the Blue Lagoon in Svartsengi high-temperature field, where a geothermal effluent pond is now one of Iceland’s most renowned tourist landmarks. Dumping water in this way would probably not be allowed today. Experience also shows that geothermal power plants attract tourists, scientists and students.

6.2.5 Uncertainty

As noted above there is certain degree of uncertainty regarding the imposed impact caused by harnessing of the geothermal reservoir on geothermal ecosystems and geothermal activity on the surface? The dynamic nature of the resource makes it even harder to identify human induces effects.

During the EIA process the ecosystems and the geothermal surface activity are usually identified and in the EIS it is stated that there may be some risk of negative impact caused by the project. In the recent projects, the developer is made fully accountable for this possible, indirect impact. This is partly based on the Precautionary Principle, which states that if an action or policy might cause severe or irreversible harm to the environment, in the absence of a scientific consensus that harm would not ensue, the burden of proof falls on those who would advocate taking the action. Instead of reaching consensus of lowering this risk by using mitigating measures like reinjection, this uncertainty has been used as grounds to halt further development. A study is being prepared to analyze and discuss how to apply uncertainty in the geothermal EIA cases.

7. CONCLUSION

The EIA process in Iceland is in continuous progress. Due to the dynamic nature of the geothermal resource, developers cannot at an early stage of development give decisive information on the scope of a given project, exact location of facilities and geothermal fluid extraction rate. Therefore one has endeavored to develop the projects in steps. This is not common for other EIA projects, and has caused some debate how to handle in the Icelandic EIA.

This also applies to the uncertainty of the environmental impact of geothermal development since all geothermal areas are dynamic in nature, causing natural fluctuations in surface activity and geothermal habitats.

The Icelandic EIA process needs to be further developed regarding geothermal development. Exploration zones must be defined in national and/or master plans so that adequate profile of the resource can be projected. Utilization zones also have to be defined adequately in master plans. This can include certain environmental conditions with regard to development, but must allow for some room for the developer to respond to information gathered from the reservoir.

The EIA process should evaluate the learning and experience gained from exploration and harnessing which can be of great value for research and development units, schools, educative tourism and the geothermal industry worldwide.

It must be looked into whether the grade scale used to assess the impact should be adapted further to fit for geothermal projects. A clear procedure must be set up how the grades are weighed together and how the weighted grade shall be used to arrive at the final decision in the EIS.

The EIA has created some vital benefits such as broad consultation and created new guidelines for the development of geothermal projects. It is important for all actors in the EIA process to learn from the experience gained from preceding steps and to improve the EIA process in general for geothermal projects, especially how to discuss and assess the uncertainty that is involved with all such projects and the complicated and diverse scientific data that the EIA decision is based on.

8. REFERENCES

Goff, S., 2000. The effective use of environmental impact

assessments (EIAs) for geothermal development

projects. Proceedings World Geothermal Congress

2000. Kyushu – Tohoku, Japan, May 28 – June 10.

597-600

Guðmundsson R., 2008. Ferdamenn og utivistarfolk a Reykjanesi 2007 (Tourists and Recreational People in Reykjanes 2007). Samantekt unnin fyrir VSO Consulting.RRF. 20 bls. In Icelandic.

Isaksson, K., T. Richardson and K. Olsson, 2009. From

consultation to deliberation? Tracing deliberative

norms in EIA frameworks in Swedish roads planning.

Environmental Impact Assessment Review, Volume

29, Issue 5, September 2009, Pages 295-304.

Kristmannsdottir, H. and H. Armannsson, 2003.

Environmental aspects of geothermal energy utilization.

Geothermics 32, 451-461.

Noorollahi, Y. and H. Yousefi, 2003. Preliminary

environmental impact assessment of a geothermal

Cheap Solar Power Here Now

2011-12-11T08:59:00.007-10:00

Solar Power Much Cheaper to Produce Than Most Analysts Realize, Study Finds

http://www.sciencedaily.com/releases/2011/12/111207132916.htm

ScienceDaily (Dec. 7, 2011) — The public is being kept in the dark about the viability of solar photovoltaic energy, according to a study conducted at Queen's University.

"Many analysts project a higher cost for solar photovoltaic energy because they don't consider recent technological advancements and price reductions," says Joshua Pearce, Adjunct Professor, Department of Mechanical and Materials Engineering. "Older models for determining solar photovoltaic energy costs are too conservative."

Dr. Pearce believes solar photovoltaic systems are near the "tipping point" where they can produce energy for about the same price other traditional sources of energy.

Analysts look at many variables to determine the cost of solar photovoltaic systems for consumers, including installation and maintenance costs, finance charges, the system's life expectancy, and the amount of electricity it generates.

Dr. Pearce says some studies don't consider the 70 per cent reduction in the cost of solar panels since 2009 . Furthermore, he says research now shows the productivity of top-of-the-line solar panels only drops between 0.1 and 0.2 percent annually, which is much less than the one per cent used in many cost analyses.

Equipment costs are determined based on dollars per watt of electricity produced. One 2010 study estimated the this cost at $7.61, while a 2003 study set the amount at $4.16. According to Dr. Pearce, the real cost in 2011 is under $1 per watt for solar panels purchased in bulk on the global market, though he says system and installation costs vary widely.

Dr. Pearce has created a calculator program available for download online that can be used to determine the true costs of solar energy.

The Queen's study was co-authored by grad students Kadra Branker and Michael Pathak and published in the December edition of Renewable and Sustainable Energy Reviews.

Story Source:

The above story is reprinted from materials provided by Queen's University.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

K. Branker, M.J.M. Pathak, J.M. Pearce. A review of solar photovoltaic levelized cost of electricity. Renewable and Sustainable Energy Reviews, 2011; 15 (9): 4470 DOI: 10.1016/j.rser.2011.07.104

The Ins and Outs of Solar Photovoltaics

2011-11-07T20:24:00.002-10:00

Berkeley Lab Research Sparks Record-Breaking Solar Cell Performances

http://newscenter.lbl.gov/feature-stories/2011/11/07/record-breaking-solar-cell-performances/

November 07, 2011

Theoretical research by scientists with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has led to record-breaking sunlight-to-electricity conversion efficiencies in solar cells. The researchers showed that, contrary to conventional scientific wisdom, the key to boosting solar cell efficiency is not absorbing more photons but emitting more photons.

“A great solar cell also needs to be a great Light Emitting Diode,” says Eli Yablonovitch, the Berkeley Lab electrical engineer who led this research. “This is counter-intuitive. Why should a solar cell be emitting photons? What we demonstrated is that the better a solar cell is at emitting photons, the higher its voltage and the greater the efficiency it can produce.”

Yablonovitch holds joint appointments with Berkeley Lab’s Materials Sciences Division and the University of California (UC) Berkeley, where he is the James and Katherine Lau Chair in Engineering, and also directs the NSF Center for Energy Efficient Electronics Science. He is the corresponding author of a paper describing this work titled “Intense Internal and External Fluorescence as Solar Cells Approach the Shockley-Queisser Efficiency Limit.” Co-authoring this paper with Yablonovitch were Owen Miller of Berkeley Lab, and Sarah Kurtz, at the National Renewable Energy Laboratory.

In their paper, Yablonovitch, Miller and Kurtz describe how external fluorescence is the key to approaching the theoretical maximum efficiency at which a solar cell can convert sunlight into electricity. This theoretical efficiency, called the Shockley-Queisser efficiency limit (SQ Limit), measures approximately 33.5-percent for a single p-n junction solar cell. This means that if a solar cell collects 1,000 Watts per square meter of solar energy, the most electricity it could produce would be about 335 Watts per square meter.

Calculations by Miller, who is a member of Yablonovitch’s research group, showed that the semiconductor gallium arsenide is capable of reaching the SQ Limit. Based on this work, a private company co-founded by Yablonovitch, Alta Devices Inc., has been able to fabricate solar cells from gallium arsenide that have achieved a record conversion efficiency of 28.4 percent.

“Owen Miller provided an accurate theory on how to reach the SQ Limit that for the first time included external fluorescence efficiency,” Yablonovitch says. “His calculations for gallium arsenide showed that external fluorescence provides the voltage boost that Alta researchers subsequently observed.”

Berkeley Lab’s Eli Yablonovitch (left) and Owen Miller showed that counter-intuitively, a great solar cell also needs to be a great Light Emitting Diode. (Photo by Roy Kaltschmidt, Berkeley Lab)

Solar or photovoltaic cells represent one of the best possible technologies for providing an absolutely clean and virtually inexhaustible source of electricity. However, for this dream to be realized, solar cells must be able to efficiently and cost-competitively convert sunlight into electricity. They must also be far less expensive to make.

The most efficient solar cells in commercial use today are made from monocrystalline silicon wafers and typically reach a conversion efficiency of about 23-percent. High grade silicon is an expensive semiconductor but is a weak collector of photons. Gallium arsenide, although even more expensive than silicon, is more proficient at absorbing photons, which means much less material is needed to make a solar cell.

“Gallium arsenide absorbs photons 10,000 times more strongly than silicon for a given thickness but is not 10,000 times more expensive,” says Yablonovitch. “Based on performance, it is the ideal material for making solar cells.”

Past efforts to boost the conversion efficiency of solar cells focused on increasing the number of photons that a cell absorbs. Absorbed sunlight in a solar cell produces electrons that must be extracted from the cell as electricity. Those electrons that are not extracted fast enough, decay and release their energy. If that energy is released as heat, it reduces the solar cell’s power output. Miller’s calculations showed that if this released energy exits the cell as external fluorescence, it would boost the cell’s output voltage.

“This is the central counter-intuitive result that permitted efficiency records to be broken,” Yablonovitch says.

Thin film solar cells fabricated from gallium arsenide have achieved a record sunlight-to-electricity conversion efficiency of 28.4 percent. (Image courtesy of Alta Devices, Inc.)

As Miller explains, “In the open-circuit condition of a solar cell, electrons have no place to go so they build up in density and, ideally, emit external fluorescence that exactly balances the incoming sunlight. As an indicator of low internal optical losses, efficient external fluorescence is a necessity for approaching the SQ Limit.”

Using a single-crystal thin film technology developed earlier by Yablonovitch, called “epitaxial liftoff,” Alta Devices was able to fabricate solar cells based on gallium arsenide that not only smashed previous solar conversion efficiency records, but can be produced at well below the cost of any other solar cell technology. Alta Devices expects to have gallium arsenide solar panels on the market within a year.

“The SQ Limit is still the foundation of solar cell technology,” says Yablonovitch. “However, the physics of light extraction and external fluorescence are clearly relevant for high performance solar cells.”

Yablonovitch believes that the theoretical work by he and his co-authors, in combination with the performance demonstrations at Alta Devices, could dramatically change the future of solar cells.

“We’re going to be living in a world where solar panels are very cheap and very efficient,” Yablonovitch says.

This research was funded by a grant from DOE’s Light-Material Interactions in Energy Conversion Energy Frontier Research Center (LMI-EFRC).

# # #

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

Additional Information

For more information about the research of Eli Yablonovitch, visit the Website at http://optoelectronics.eecs.berkeley.edu/

For more information about the LMI-EFRC, visit the Website at http://www.lmi.caltech.edu/

For more information about Alta Devices, Inc., visit the Website at https://www.altadevices.com/

Solar To Get Better and Cheaper

2011-11-04T18:08:00.004-10:00

http://scienceprogress.org/2011/10/new-solar-technology-you-never-heard-of/

PROCESS INNOVATION

The Coolest New Solar Manufacturing Technology You’ve Never Heard Of

Publicly Funded Research Leads to Breakthrough in Solar Cell Production

SOURCE: NREL/Dennis Schroeder The cavity inside the Solar Optical Furnace glows white hot during a simulated firing of a solar cell.

By Lauren Simenauer and Sean Pool | Friday, October 28th, 2011

Too often, when talking about research and innovation on clean energy technologies, policymakers, pundits, and the media tend to assume that the biggest breakthrough will come from a completely novel technology. The discovery of some new and sexy clean energy technology will suddenly change the game and make clean energy abundant and affordable overnight.

In practice that rarely happens. A more likely scenario is that humble, behind-the-scenes “process innovations” will continue to increase the efficiency and drive down the costs of manufacturing the technologies we already know work.

The Department of Energy has recently completed testing on just such a humble breakthrough. The Optical Cavity Furnace is a new piece of equipment for making solar cells that is about to rock the photovoltaic industry by slashing costs and increasing efficiency. The news should not just excite tech nerds—by reducing the cost of producing solar cells by nearly three-quarters, this new technology represents another big step on the path to making clean energy the cheap kind of energy.

Here’s how it works. By using optics to more efficiently focus visible and infrared light, the Optical Cavity Furnace can heat silicon wafers used in solar cell production much more precisely and uniformly than previous forms of solar cell manufacture. The resulting solar cells are stronger, more efficient, and have fewer impurities. The National Renewable Energy Lab, or NREL, the DOE office responsible for the research, and a corporate partner AOS Inc. are now working to bring this technology to scale. The partners plan to build an industrial-scale Optical Cavity Furnace capable of producing 1,200 highly efficient solar cells per hour. NREL has cooperative research agreements with many of the country’s biggest solar cell producers.

Even better, in addition to producing solar cells more reliably, quickly, and therefore cheaply, the Optical Cavity Furnace itself is cheaper than traditional equipment used to produce cells. As the cost of manufacturing solar cells goes down, elementary economics suggests the accessibility of solar cells will soar. Then it’s a matter of harnessing their power in a myriad of other industries in a clean energy domino effect.

The White House has challenged the solar industry to produce clean electricity at $1 per watt. It has also set a national goal to achieve 80 percent clean energy use by 2035. Though some tout the idea that radically new breakthroughs in energy technology are needed to achieve these goals, incremental process innovation in existing technologies is perhaps a more important part of the solution. Innovations like the Optical Cavity Furnace that make the technologies we already know about cheaper, easier to produce, and more abundant can have game-changing impacts on bringing clean energy to scale.

The concept of “grid parity”—the point at which generating electricity from alternate energy sources is equivalent in cost to generating electricity from grid power—underlies the feasibility of using solar cells as a resource. Due to the competing forces of supply and demand, consumers likely will not choose clean energy until it is cheap and convenient. The good news is that researchers are racing toward that goal at an impressive rate.

In fact, the cost of photovoltaic, or PV, cells had already fallen 50 percent in the past two years prior to the DOE announcement. A June 2011 projection predicted PV module prices would hit the goal of $1 per watt by 2013; now the finish line of the proverbial “race to the bottom” seems even more imminent.

For consumers weary of the daily media promises of a cure-all solution to climate change, consider this: Deflating prices of solar cell manufacturing mirror the downward price slope of other technologies we now take for granted, like cell phones and DVD players. One important driver of those price declines is process innovation. And the government, instead of being an obstacle to competition, is uniquely poised to foster it, as evidenced by the new DOE solar furnace. In addition to the work being done at the Department of Energy’s National Renewable Energy Laboratory, dozens of other federal labs across the country under the DOE Office of Science, the National Institute of Standards and Technology, and the Manufacturing Extension Partnerships are helping push the bounds of process innovation in clean energy manufacturing.

The notion that science or innovation alone can solve our energy and climate challenges may seem like the overoptimistic ramblings of an enthusiastic technocrat. Yet new technologies like the Optical Cavity Furnace are piling up, creating a stronger and stronger rationale for increased federal investment in innovation. Through process innovation, we increase efficiency and lower costs, virtually negating the common arguments against climate-conscious energy policy. Like it or not, most consumers still make energy choices based on the impact those choices have on their wallets rather than based on the impact they have on the environment. With a vibrant national research ecosystem that fosters process innovation, before we know it, more and more consumers will be choosing clean energy not because it is the socially conscious choice but because it’s the cost-effective choice.

The Best Centralized Solar Solution

2011-07-21T08:47:00.004-10:00

Twice the height of the Empire State - EnviroMission plans massive solar tower for Arizona

http://www.gizmag.com/enviromission-solar-tower-arizona-clean-energy-renewable/19287/

By Loz Blain

11:03 July 21, 2011

24 Pictures

EnviroMission's solar tower: coming to Arizona in 2015

Image Gallery (24 images)

An ambitious solar energy project on a massive scale is about to get underway in the Arizona desert. EnviroMission is undergoing land acquisition and site-specific engineering to build its first full-scale solar tower - and when we say full-scale, we mean it! The mammoth 800-plus meter (2625 ft) tall tower will instantly become one of the world's tallest buildings. Its 200-megawatt power generation capacity will reliably feed the grid with enough power for 150,000 US homes, and once it's built, it can be expected to more or less sit there producing clean, renewable power with virtually no maintenance until it's more than 80 years old. In the video after the jump, EnviroMission CEO Roger Davey explains the solar tower technology, the Arizona project and why he couldn't get it built at home in Australia.

View all

How Solar Towers Work

Enviromission's solar tower is a simple idea taken to gigantic proportions. The sun beats down on a large covered greenhouse area at the bottom, warming the air underneath it. Hot air wants to rise, so there's a central point for it to rush towards and escape; the tower in the middle. And there's a bunch of turbines at the base of the tower that generate electricity from that natural updraft.

It's hard to envisage that sort of system working effectively until you tweak the temperature variables and scale the whole thing up. Put this tower in a hot desert area, where the daytime surface temperature sits at around 40 degrees Celsius (104 F), and add in the greenhouse effect and you've got a temperature under your collector somewhere around 80-90 degrees (176-194 F). Scale your collector greenhouse out to a several hundred-meter radius around the tower, and you're generating a substantial volume of hot air.

Then, raise that tower up so that it's hundreds of meters in the air - because for every hundred metres you go up from the surface, the ambient temperature drops by about 1 degree. The greater the temperature differential, the harder the tower sucks up that hot air at the bottom - and the more energy you can generate through the turbines.

Because it works on temperature differential, not absolute temperature, it works in any weather;
Because the heat of the day warms the ground up so much, it continues working at night;
Because you want large tracts of hot, dry land for best results, you can build it on more or less useless land in the desert;
It requires virtually no maintenance - apart from a bit of turbine servicing now and then, the tower "just works" once it's going, and lasts as long as its structure stays standing;
It uses no 'feed stock' - no coal, no uranium, nothing but air and sunlight;
It emits absolutely no pollution - the only emission is warm air at the top of the tower. In fact, because you're creating a greenhouse underneath, it actually turns out to be remarkably good for growing vegetation under there.

The Arizona Project

While this is not the first solar tower that has been built (a small-scale test rig in Spain proved the technology more than a decade ago) EnviroMission has chosen to build its first full-scale power plant in the deserts of Arizona, USA.

The Arizona tower will be a staggering 800 metres or so tall - just 30 meters shorter than the colossal Burj Khalifa in Dubai, the world's tallest man-made structure. To put that in context - it will stand more than double the height of the Empire State building in New York City, and it'll be as much as 130 meters in diameter at the top. Truly a gigantic structure.

Currently undergoing site-specific engineering and land acquisition, EnviroMission estimates the tower will cost around US$750 million to build. It will generate a peak of 200 megawatts, and run at an efficiency of around 60% - vastly more efficient and reliable than other renewable energy sources.

The output has already been pre-sold - the Southern California Public Power Authority recently signed a 30-year power purchase agreement with EnviroMission that will effectively allow the tower to provide enough energy for an estimated 150,000 US homes. Financial modelling projects that the tower will pay off its purchase price in just 11 years - and the engineering team are shooting for a structure that will stand for 80 years or more.

Considering that a large city like Los Angeles requires total power in the region of 7,200 megawatts, you'd have to build a few dozen solar towers up to the same size as the Arizona project if you wanted to completely replace the existing, primarily coal-based energy supply for that city's 3.7 million-odd residents. So it's not an instant solution - but then, its short projected payback period and virtually zero operating costs make it a very sound economic proposition that competes favorably against other renewable sources.

Under the terms of the pre-purchase agreement, the Arizona tower is due to begin delivering power at the start of 2015. Watch this space!

http://www.gizmag.com/enviromission-solar-tower-arizona-clean-energy-renewable/19287/

Solar Adds Value To Home

2011-04-22T12:41:00.001-10:00

Photovoltaic Systems Boost the Sales Price of California Homes

ScienceDaily (Apr. 21, 2011) — New research by the U.S. Department of Energy's (DOE) Lawrence Berkeley National Laboratory finds strong evidence that homes with solar photovoltaic (PV) systems sell for a premium over homes without solar systems.

"We find compelling evidence that solar PV systems in California have boosted home sales prices," says the lead author Ben Hoen, a researcher at Berkeley Lab. "These average sales price premiums appear to be comparable with the average investment that homeowners have made to install PV systems in California, and of course homeowners also benefit from energy bill savings after PV system installation and prior to home sale."

The research finds that homes with PV in California have sold for a premium, expressed in dollars per watt of installed PV, of approximately $3.90 to $6.40/watt. This corresponds to an average home sales price premium of approximately $17,000 for a relatively new 3,100 watt PV system (the average size of PV systems in the Berkeley Lab dataset), and compares to an average investment that homeowners have made to install PV systems in California of approximately $5/W over the 2001-2009 period.

"This is a sizeable effect," says Ryan Wiser, a Berkeley Lab scientist and co-author. "This research might influence the decisions of homeowners considering installing a PV system and of home buyers considering buying a home with PV already installed. Even new home builders that are contemplating PV as a component of their homes can benefit from this research."

Approximately 2,100 megawatts (MW) of grid-connected solar PV have been installed in the U.S. California has been and continues to be the country's largest market for PV, with nearly 1,000 MW of installed capacity. California is also approaching 100,000 individual PV systems installed, more than 90% of which are residential. Though an increasing number of homes with PV systems have sold, relatively little research has been performed to estimate the impacts of those PV systems on home sales prices.

The Berkeley Lab research is the first to empirically explore the existence and magnitude of residential PV sales price impacts across a large number of homes and over a wide geographic area. The research analyzed a dataset of more than 72,000 California homes that sold from 2000 through mid-2009, approximately 2,000 of which had a PV system at the time of sale. "This is the most comprehensive and data-rich analysis to date of the potential influence of PV systems on home sales prices," says co-author and San Diego State University Economics Department Chair Mark Thayer.

The research controlled for a large number of factors that might influence results, such as housing market fluctuations, neighborhood effects, the age of the home, and the size of the home and the parcel on which it was located. The resulting premiums associated with PV systems were consistent across a large number of model specifications and robustness tests.

The research also shows that, as PV systems age, the premium enjoyed at the time of home sale decreases. Additionally, existing homes with PV systems are found to have commanded a larger sales price premium than new homes with similarly sized PV systems.

"One reason for the disparity between existing and new homes with PV might be that new home builders also gain value from PV as a market differentiator that speeds the home sales process, a factor not analyzed in the Berkeley Lab study," says Berkeley Lab researcher and co-author Peter Cappers. "More research is warranted to better understand these and related impacts."

This work was supported by the Office of Energy Efficiency and Renewable Energy (Solar Energy Technologies Program) of the U.S. Department of Energy, by the National Renewable Energy Laboratory and by the Clean Energy States Alliance.

Download the full report, “An Analysis of the Effects of Residential Photovoltaic Energy Systems on Home Sales Prices in California”

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by DOE/Lawrence Berkeley National Laboratory.

http://www.sciencedaily.com/releases/2011/04/110421122408.htm

All Energy From Solar in 20 Years?

2011-02-23T07:39:00.003-10:00

Famed Futurist: "We Can Meet All Our Energy Needs from Solar in 20 Years"

Ray Kurzweil is arguably the world's most famous futurist. He laid out the law of accelerating returns, which states that technology improves at exponential rates, and made a string of dead-on predictions about computing in the 80s -- that a computer would beat a man at chess by 1998, and that the world would link networks into some crazy globally connected system sometime in the mid-90s. Now, Kurzweil is talking solar. In an interview with Grist, he explains why he's not worried about climate change, and how renewable energy sources will become dominant much, much sooner than we think.

He explains his techno-optimism to Grist:

One of my primary theses is that information technologies grow exponentially in capability and power and bandwidth and so on. If you buy an iPhone today, it's twice as good as two years ago for half the cost. That is happening with solar energy -- it is doubling every two years. And it didn't start two years ago, it started 20 years ago. Every two years, we have twice as much solar energy in the world. Today, solar is still more expensive than fossil fuels, and in most situations it still needs subsidies or special circumstances, but the costs are coming down rapidly ... we are only a few years away from parity.
So right now it's at half a percent of the world's energy. People tend to dismiss technologies when they are half a percent of the solution. But doubling every two years means it's only eight more doublings before it meets a 100 percent of the world's energy needs. So that's 16 years. We will increase our use of electricity during that period, so add another couple of doublings: In 20 years we'll be meeting all of our energy needs with solar, based on this trend which has already been underway for 20 years.

That's some major optimism indeed -- unfortunately, even if the technology itself got good enough that quickly, it in no way accounts for the massive task of deploying enough solar farms fast enough to render coal and natural gas plants obsolete. Many scientists say, after all, that we're going to need to drastically scale down emissions in 10 years time before we irrevocably alter our climate.

Furthermore, breakthroughs in clean energy technology have not occurred at an analogous rate to information tech -- they're much rarer, for a variety of reasons.

Finally, the most glaring miscalculation I think Kurzweil makes is that unlike the computing industry, there's an entrenched, powerful industrial opposition to clean energy that will actively work to stymie its advances whenever feasible in the political arena. Computers were developing into a wide open space in the market, with no comparable oppositional industry ready to compete with them -- the typewriter industry doesn't exactly have the same clout as the coal and oil industries. Perhaps if there wasn't a preexisting, artificially cheap energy source that was widely relied upon, and whose operators had access to major power levers, Kurzweil's time line could come true -- but since there is, we won't see the same kind of investment, excitement, and innovations in clean tech until use of dirty fuels is formally discouraged.

Kurzeil is right that we could power the world with clean energy in 20 years. But relying on technology alone isn't likely to get us there.

By Brian Merchant | Sourced from Treehugger

http://www.alternet.org/newsandviews/article/481791

Comment By Jonathan Cole

For most of the past 30 years I have been living on solar and developing practical solar energy systems that provide energy for all of the modern amenities, are durable, low-maintenance and user-friendly. I never had a power outage or burned out even a light bulb.

This technology, properly designed and installed already competes with the grid even without any subsidy. Why? Because once the equipment is installed, the fuel is free. Since a properly made system can last from 25 to 40 years, you save a lot of money on avoided fuel costs. I don't pay any electrical bill and am totally independent of the grid. I have all modern amenities.

The reason Kurzweil is correct and the author of the article is dubious, is because the author has his facts wrong. Computers and the internet have had huge resistance from entrenched change-averse interests in the publishing, entertainment, telecommunications and other industries whose bottom lines are being destroyed by the new technologies.

There is a way to do a complete end-run around the utility monopolies/oligarchies who are certainly dragging their feet in many instances. That is to create an integrated solar energy appliance that is mass-producible, just like the computer is a mass-producible integrated information processing appliance.

That has yet to be done because the world is currently in a frenzy of speculation instead of productive investment. While a certain amount of speculation may play a healthy role in an economy, an absolutely uncontrolled speculative frenzy, destroys wealth and reduces the productivity required for progress.

We need visionary investors who realize the importance of productive investment to support the development of these integrated solar appliances. Once a UL approved solar energy appliance is developed that can be plugged into the home with a minimum of red-tape, the power industry will be forced to join in or be rendered obsolete.

And by the way, to do this requires nothing to be invented, only adapted and refined. So based on experience, knowledge and facts, Kuzweil's prediction is totally on track. Jonathan Cole, MBA http://lightontheearth.blogspo.../

Eliminate Waste and Accelerate Renewables-Use

2011-01-10T08:42:00.004-10:00

Get a fast education at

http://awesome.good.is/transparency/web/1101/good-energy/interactive.html

How to turn Global Warming into an Asset

2010-07-20T11:48:00.001-10:00

Tuesday, January 29, 2008

Energy Island: unlocking the potential of the ocean as a renewable power source

Image Gallery (5 images)

January 29, 2008 While governments and corporations were exploring petroleum as a fuel source in the 19th century, Jacques Arsene d’Arsonval proposed another liquid source for power – the ocean. It may have taken a hundred years, but his ideas are finally starting to come into fruition. Ocean Thermal Energy Conversion uses the temperature difference between surface and deep-sea water to generate electricity – and though it has an efficiency of just 1-3% - researchers believe an OTEC power plant could deliver up to 250MW of clean power, equivalent to one eighth of a large nuclear power plant, or one quarter of an average fossil fuel power plant. Architect and engineer Dominic Michaelis and his son Alex, along with Trevor Cooper-Chadwick of Southampton University are developing the concept with plans of putting the theory to the test on an unprecedented scale by building a floating, hexagonal Energy Island that will harness energy from OTEC, as well as from winds, sea currents, waves, and the sun.

The US National Renewal Energy Laboratory estimates that the world’s tropical seas absorb the solar power equivalent of 250 billion barrels of oil per day. OTEC uses warm surface water to vaporize a fluid with a low boiling point, typically ammonia or propane, and pumps cooler water from depths of up to 1000 meters below the surface to re condense the fluid. The movement of the liquid through the system is enough to continually power a turbo-generator. The simplistic nature of the station, which behaves almost like a gigantic internal combustion engine, allows OTEC power plants to be largely self-sufficient. And unlike wind and solar energy, which have a fluctuating output that changes according to the weather and the time of day, the regularity of ocean temperatures and movements provide a far more stable and consistent source of power.

The Energy Island project is bidding for the US$25 million funding offered by Richard Branson’s Virgin Earth Prize, which is awarded for environmentally responsible research. The OTEC technology is something of a green dream; not only is it clean and renewable, but so are its by-products. By subjecting the steam to electrolysis, large quantities of hydrogen can be produced, paving the way for cheaper hydrogen fuel cells. And by using an Open-cycle OTEC - where low-pressure containers boil seawater and condense the steam elsewhere after passing it through the turbo-generator – large amounts of fresh water can be created. Energy Island is also packed to the brim with other renewable energy collectors, with wind, wave, current and solar sources providing a total of 73.75 MW.

Michaelis estimates it would take a chain of 4-8 Energy Islands to achieve the production levels of a nuclear power plant. To replace nuclear power entirely, Michaelis estimates a chain of 3708 modules would be required, stretched over a total length of 1928 kilometres, and consuming a total square area of roughly 30 by 30 kilometres. To shoulder the entire global energy consumption, based on 2000 figures, 52 971 Energy Islands would be needed, occupying a total area of 111 x 111 kilometres - described on the Energy Island site as “a pin point in the oceans.” Though the Islands have to be spread out to be effective, their location doesn’t infringe on otherwise usable real estate, as is the case with land power stations, and some bioethanol farms. Michaelis claims that in certain areas, chains of Energy Islands may even help maintain the environment, by combating erosion from the predicted rising sea levels, supporting deep-water ecosystems and aquaculture, and cooling greenhouses.

Energy Island isn’t the first project to portray OTEC as the solution to Earth’s power and pollution woes. Previous plans for the technology, most notably John Craven’s, have been positively utopic. Craven saw OTEC not only as a source of cheap power and water, but also as a method for accelerating crop growth, and, (no utopia would be complete without it), a provider of free air conditioning. Project Windfall, meanwhile, was a plan authored by a Florida group that involved installing an OTEC plant in order to reduce the hurricanes that routinely ravage the east coast.

But while OTEC has captured the imagination of scientists, it has not had nearly so much success with governments. The United States established the Natural Energy Laboratory of Hawaii Authority in 1974, viewing the high electricity costs of the state, and the dynamics of the surrounding water, as the ideal testing ground for OTEC technology. The NEL successfully demonstrated a 250 kW closed-cycle plant in 1999, but ultimately the money evaporated faster than the water, and Congress shifted attention to more economical areas of research. OTEC could be commercially viable, said test director Luis Vega, but it needed “patient funding” to reach that stage.

Only now, with rising oil prices and the increasingly cataclysmic predictions of global warming, could OTEC receive the “patient funding” necessary for progress. Plans for OTEC plants are being entertained by the governments of Japan, Taiwan, India, South Africa, the Philippines and the US, which recently passed a bill that gives OTEC, and tidal, wave, and ocean current research, $50 million per year for five years.

However, the next breakthrough in OTEC research may well come from the armed forces. The US government has been directing its various departments into funding and using renewable energy – in an example that must give Democrats migraines of confusion, Guantanamo Bay receives a quarter of its power from wind energy. By 2025, the Pentagon is to increase its renewable energy use to 25% of its total power. The Navy is planning to build an 8MW OTEC facility in 2009, near the island of Diego Garcia in the Indian Ocean, while the Army is planning to build an OTEC facility in the Marshall Islands in the Pacific.

As the Energy Island site states, despite being 100 years old, OTEC is in its infancy. But given the renewed interest, and the multitude of various benefits, it’s possible that the next 100 years of this concept could profoundly change the energy and environmental management of the Earth.

Conservation and Efficiency First Steps to Solar

2010-07-14T15:48:00.000-10:00

http://www.renewableenergyworld.com/rea/news/recolumnists/story?id=53526

September 9, 2008

Inflate This: Conservation and Efficiency Are Key to Our Energy Future

by Ron Pernick

Of the recent political maneuvering and verbal attacks in the current presidential election, perhaps one of the most disappointing and frustrating has been John McCain's disparagement of conservation and efficiency. Mocking Obama's call for Americans to make sure their tires are properly inflated to help reduce gasoline consumption: The McCain team started handing out tire gauges to journalists and editors engraved with the words: "Obama's Energy Plan."

Give me a break!

It's time that serious and informed policymakers stop putting down one of the most effective energy sources of all: conservation and efficiency (or what some people call the "fifth fuel.") There's nothing funny about disparaging one of our most valuable energy assets. It's common knowledge among energy experts that the lowest hanging fruit is often conservation and efficiency. And I believe that most traditional "conservatives" in the mold of Theodore Roosevelt and British statesman Edmund Burke (often credited with founding modern conservatism) understand the value of energy "conservation."

Conservation and efficiency also make good economic sense. In some research my colleagues and I recently conducted at Clean Edge, we analyzed the capital costs to deploy a range of energy generation and energy reduction measures for utilities. In most cases, energy conservation efforts (everything from implementing energy efficiency programs to demand side management) came in as the least expensive option.

On the automobile front, the Department of Energy estimates that "you can improve your gas mileage by around 3.3 percent by keeping your tires inflated to the proper pressure." Combined with regular tune-ups, replacing clogged air filters, and using the right oil grade, the U.S. Department of Energy estimates that the average driver could save 18-19 percent combined. So how much savings are we talking about? According to the U.S. Government Accountability Office, about 1.2 billion gallons of fuel per year could be saved from properly inflated tires alone (equal to about one percent of total gasoline consumption).

And many of these conservation measures can be done in very short order.

By contrast, opening up drilling in areas that are currently off-limits in the Gulf of Mexico and off the Atlantic and Pacific Coasts of the lower 48 states are estimated to be just slightly more than the savings that could be achieved via proper tire pressure. The Energy Information Administration projects that there's about 1.5 billion gallons of gasoline a year that could be accessed from new offshore drilling, but that it wouldn't come online for years. To be fair, some industry estimates show that this number could be much higher, but no clear metrics exist.

Amory Lovins and Hunter Lovins, in their 1998 Club of Rome report Factor Four: Doubling Wealth, Halving Resource Use, outlined how to do just that: double the world's wealth while cutting the use of our resources in half. They wrote in the book's introduction: "‘Factor Four,' in a nutshell, means that resource productivity can — and should — grow fourfold. The amount of wealth extracted from one unit of natural resources can quadruple. ...it heralds nothing less than a new direction for technological ‘progress.'"

These remain awfully sage words in today's carbon- and resource-constrained world.

But in his attempt to score political points by painting Obama in some cardigan-wearing, Carteresque light — McCain did a disservice to the broader energy dialogue. It harkens back to Vice President Cheney's discounting of energy efficiency more than seven years ago, when he stated "Conservation may be a sign of personal virtue, but it is not a sufficient basis for a sound, comprehensive energy policy."

The future of energy in the U.S. will involve a combination of many different technologies, policies and business approaches. There is no one silver bullet. In my estimation, we're talking about the massive scale up of solar, wind and other non-hydro clean-energy sources (getting to 30 percent of the nation's electricity generation by around 2030); the extensive build-out of green buildings and energy-sipping built environments; the deployment of a smart grid and plug-in hybrid and all-electric vehicles; and yes, energy efficiency measures as simple as tuning one's car and weatherizing one's house for the winter.

The issues we face will require an integrated, whole-systems approach that utilizes the best weapons in our clean-energy arsenal. In fact, a review of both Obama's and McCain's web sites, point to a range of options and policy recommendations by both candidates. Implying otherwise is simply ludicrous.

And, I believe, near the center of any 21^st Century energy plan should sit a robust energy efficiency and conservation component — one that is exemplified rather than belittled.

Ron Pernick is co-founder and managing director of Clean Edge, Inc., coauthor of The Clean Tech Revolution, and Sustainability Fellow at Portland State University's School of Business.

Comments on article:
Actually, what is even harder to understand than brain-dead politicians like Cheney and McCain, is why individuals who can easily afford it don't simply start upgrading their equipment to the most efficient available including cars, housing, and appliances. The return on investment is way better than the stock market in most cases and will only get better as energy prices increase. Could it be that no-brainism is contagious?

Dump those gas guzzlers. Get those efficient refrigerators, laundry appliances and triple glazed windows. They will never again be cheaper than they are now (because inflation and currency devaluation never stop).

My guess is that if everyone in the U.S. who could afford to do so, would take these steps, we could reduce our energy use by 15-25% and the investment would be repaid in reduced operating costs within 2-7 years. So let's stop "Dicking" around (sounds so much better than 'Cheney-ing' around) and save ourselves and our children from a collapse of the biological foundations of life. That is a no-brainer.

Micro-Inverters are the best solution

2010-07-14T15:44:00.000-10:00

September 8, 2008

Time for a Change: Micro-inverters Improve Performance of Solar Systems

by Raghu Belur, Enphase Energy

There are many challenges in current solar technology. These challenges include the inefficiencies in photon-to-electron conversion, system reliability, and the difficulties in installing and managing solar installations. The majority of current research and development funding is looking to address the first issue by focusing on improvements in solar module technology and manufacturing. While this is important to drive down the cost of solar modules, there are additional opportunities for improvement in solar system performance. Re-thinking the role inverters can play in solar installations is one way to address the challenges associated with energy harvest, reliability and management of solar systems.

Traditional Inverters

Inverters perform two key functions — converting the DC power from the solar modules into grid quality AC power and performing Maximum Power Point Tracking (MPPT) on the solar array. MPPT is the algorithm that extracts the maximum amount of power from the solar array.

Traditional centralized inverters manage all the solar modules in an array as an aggregate — a single source of energy. But there are limitations in using a single MPPT for multiple solar modules. Non-uniform changes in temperature, irradiance and shading create complex heterogeneous current-voltage curves, making it difficult for an MPPT algorithm to operate efficiently. This can result in the conversion of less than the maximum power available from the solar modules. An associated issue is that a traditional inverter represents a single point of failure in the solar system. A final limitation of traditional inverters includes noise pollution, space constraints and aesthetic issues. The larger the solar power system, the larger the inverter that is required, sometimes requiring a separate facility that must be constructed, powered, cooled and maintained.

The Micro-inverter Systems Approach

The idea of a micro-inverter has existed for many years — using multiple small inverters instead of a large, centralized inverter to distribute the power conversion of a solar installation. Early designs met with limited success because they failed to achieve the efficiency, reliability and price point required to achieve regulatory and commercial viability. More recent designs such as one from from Enphase have taken these lessons to heart, and micro-inverters are being developed and tested to meet the industry regulations and customer requirements. What is emerging is a micro-inverter that produces more energy, is more reliable and less expensive to install and maintain than traditional inverters.

Harvest Gains, Reliability, Design and Installation

Micro-inverter technology offers significant technological advances. The first is per-module MPPT, which ensures energy harvest is maximized. With traditional inverters, the performance of the entire array is degraded if one or more modules becomes dusty, covered in debris or shaded. Micro-inverters enable each module to perform independently within the solar array. This benefits the system owner by maximizing energy harvest since degraded performance from one solar module will not prevent the rest of the modules from producing their maximum energy. The per-module micro-inverter also eliminates the problem of reduced energy harvest due to module mismatch. Tests have shown an increase in energy harvest in the order of 5 to 25%.

As with the migration from a central mainframe to personal computers in the information technology industry, the distributed nature of the micro-inverter system significantly alters the landscape of the solar industry. A centralized inverter failure in a traditional design renders the entire solar array useless until a replacement can be ordered and installed. With a micro-inverter approach, a single inverter failure only affects the module to which it's attached, and contributes to an insignificant degradation in total system output. This means that micro-inverters can be replaced at the convenience of the installer or during a regularly scheduled maintenance visit. In addition, no specialized personnel, equipment or tools are required to replace a micro-inverter. This distributed approach can achieve system availability of greater than 99.8 percent — a key factor for commercial systems.

The micro-inverter approach also promises to increase design flexibility and lower installation costs. Micro-inverters are connected in AC branch circuits eliminating the need for expensive DC combiner boxes, disconnects etc. This means that installers no longer have to deal with restrictions of string design or with the headache of locating and installing a large traditional inverter. Individual solar modules no longer have to be "matched" because each module is an independent energy producer with its own MPPT. Use of micro-inverters eliminates the hassle of working around varying module ratings and standardizes the installation process. The per-module inverter approach means that installers have the flexibility to install solar modules on any available roof surface without the restriction of coplanarity.

Enphase Energy has extended the concept of a micro-inverter into a complete system, which includes the micro-inverter, embedded powerline communications and Enlighten — a web-based performance monitoring and analysis tool. The tool is able to compare modules and if it notices an energy harvest issue, it uses built-in algorithms to analyze the cause of the issue and whether the owner or installer needs to be notified.

With a systems approach to solar generation that delivers greater productivity, higher reliability and smart management, micro-inverter systems significantly improve the performance of solar systems.

Raghu Belur is a co-founder and vice president of marketing at Enphase Energy Inc. He has 15 years of experience in engineering and engineering management. He began his career at the Indian Institute of Science where he worked on a team developing an alternative energy gasification system. He was an early engineer at Cerent Corporation where he was responsible for the development of the optical 2.5Gig interface for the Cerent-454 ADM. Cerent was acquired by Cisco Systems in 1999. At Cisco, Raghu was managing the team developing the 10Gig interface products. He co-founded Enphase Energy Inc in March of 2006. Raghu has a MSEE from Texas A&M University.

comments:

From Jonathan Cole:

Excellent, Raghu! I have been trying to promote this approach for decades. Finally it is getting done. Another incredible advantage to this approach is longevity. Small inverters (and charge controllers) at 90%+ efficiency dissipate hardly any heat because the load of the entire array is distributed into such small packets. This means the long-term heating issues that degrade components in larger inverters are no longer an issue. It means that passive heat dissipation such as radiative cooling and micro heat pumps are viable instead of having to rely on fan driven systems which are a point of failure in a system made to last 15 years or more. This amounts to longer life and lower cost.

Since such mini inverter modules can be plugged into the back of a solar panel, much as you might plug a nightlight into a receptacle, replacement takes minutes. This then means that advanced technology upgrades are viable which is important over the life of a solar electric system since it may be as log as 40 or 50 years.

I have a friend who has been operating a 300 watt inverter continuously for 15 years without a failure. Packaging all components into individual panels is the way to go. Now when we include energy storage such as the lithium titanate batteries being offered by Altairnano, we come up with the ultimate self charging uninterruptible power supply. Take it to mass production, and the energy problem is on its way to being solved.

Comments From Ben Gatti

Jonathan,
Spreading the heat components around, makes it more expensive to manage the heat not less. When the heat is close, you can use fans, heat-sinks, and temperature sensors to control heat, with active heat control, one can use the full capacity of the components.

If many large inverters where more cost effective than larger ones, there would be no market and a negative price curve for larger inverters. In Fact, inverters at the high end of the power continuum are about half the cost per watt as those at the low end.

Having serviced residential and commercial low-voltage systems in the past, I am somewhat skeptical of the savings long-term. A single point of failure can be very easy to diagnose; while finding a problem somewhere on a high, hot, and sloped roof, at the end of a long ladder, is more dangerous and more expensive.

On flat commercial roofs, you can get away with equipment spaghetti, but on a sloped roof; I would prefer as little as possible up there, and as much as possible mounted in a cool place at eye level, but that's the been-there-done-that part of me talking.

I do like the idea of better MPPT efficiency, and fully scalable systems; But micro-inverters will need to be fully integrated into the Panel before the pros outweigh the cons.

Reply from Jonathan Cole:

Ben, You clearly have not looked at the instrumentation demo on EnPhase's website. With this advance in instrumentation there is no longer any diagnosis necessary. You know what you need too fix before you even go up on the roof. And while economies of scale may now favor large inverters, that is only because all of these products are not yet in the true realm of advanced automated mass production. When these things are being manufactured in the hundreds of millions of units, I guarantee you that they will be dirt cheap

Ben, I think you may be misinterpreting the way such a system would work. It is true that with a single inverter you would not have to go up on the roof. On the other hand with the micro-inverter system, with each panel putting out AC and running in parallel, if one fails, you won't need to go on the roof until a convenient time. Because even if 15% of your panels fail, you are not out of business. But with a single inverter, failure is a complete power outage. Since small inverters will be more reliable because they don't have mechanical heat dissipation, there should be much less need for repair. The ideal is to have inverters that can last the life of the PV and even to be economically upgradable, since electronic technology continues to improve over the 30-50 year life of the PV.

When the inverter and charge controller are integrated with the panels it means that a single AC wire can come from the entire array which seems like much fewer connections and much less wire cost to me. And the data for the instrumentation can be multiplexed on the electrical signal so that no additional wiring is required for complete AC/DC instrumentation.

As far as connecting batteries into such a system, they are connected between the charge controller and the inverter, just as in every un-integrated independent system - like the one I have been living on for 26 years. I am sure that EnPhase is probably targeting the grid-tied market, but it is only a relatively small step to integrate storage when the economic issues are supportive.

Cheaper per watt has to include the maintenance and installation costs, including wiring, and enclosures for weather protection, etc. Even in Hawaii we have these costs and they are significant. We need an integrated product that can be installed in a morning and supply sophisticated data reports, querying, alarms and instrumentation to have user-friendly, 30-50 year installations with high reliability.

This awaits visionary investors.

Comment From Ben Gatti:

Jonathan,
I appreciate your points - I do, But I think you've failed to make the case for three key points:

1. That a transistor sitting on a roof will run cooler than in the moderate temperatures of a shaded garage. Try this experiment, park your car in a garage, then park it in the hot sun; use the vinyl seat test or some other scientific method. Trust me that roof is a hotter environment.

2. A Single failure won't cause a problem. This I think is a maybe. Ever had a Mosfet fail? It shorts. Not sure what would happen if a few Mosfets short over; maybe not much. But saying doesn't make it so.

3. How do you include batteries in a one-panel, one inverter system? If I understand you correctly, You'd have batteries behind each panel, connected between the "Charge Controller" and the inverter. That would mean climbing the roof to replace the batteries. Now you have to admit that's a bit of a tricky wicket.

Reply from Jonathan Cole:

Actually the development of panel mounted inverters already goes back quite a way. The first that I heard of was an Australian firm. They did not have the right design and went under. Lately, Exceltech has come out with this product on the market.
http://www.exeltech.com/pvacproduct.htm

Before you get too sure that this is a bad idea, you might want to look a little closer. Actually underneath a PV panel remains remarkably cool. One quarter inch from the back of my Kyocera panels in Hawaii on a full-sun summer day at noon (we have very strong sun), it is the same as ambient temperature. If you put your hand back there it does not feel any warmer than the air. Most of the heat dissipated from most solar panels rises (because heat rises) and does not come out the back of the panel. This is why here in Hawaii, large hotels are covering there roof with PV, because they generate electricity and lower their cooling costs at the same time. PV on a roof is a heat interceptor and dissipates nearly all of it upward. As far as being able to put a battery pack back there as well, you might want to check out
http://www.b2i.cc/Document/546/NanoSafeBackgrounder060920.pdf

Integrated PV/electronics/storage is the future in my opinion. The fact is, that without storage there is a limit to how much time-variant solar energy can be utilized by the grid. Of course it might put a lot of old style installers out of business, but only if they refuse to see the writing on the wall, because once these products are in mass production, the demand will be enormous. So it might only take a few hours for the installation of the entire system, but there will be millions of systems to install instead of tens of thousands.

Don't forget that 100 years ago, every automobile was a custom, one of a kind integration of a hodgepodge of parts. Mass production is what changed things and it will be no different with integrated PV/electronics/storage systems

Solar Breakthrough

2010-07-14T15:38:00.002-10:00

http://www.sciencedaily.com/releases/2008/11/081103130924.htm

Solar Power Game-Changer: 'Near Perfect' Absorption Of Sunlight, From All Angles

ScienceDaily (Nov. 4, 2008) — Researchers at Rensselaer Polytechnic Institute have discovered and demonstrated a new method for overcoming two major hurdles facing solar energy. By developing a new antireflective coating that boosts the amount of sunlight captured by solar panels and allows those panels to absorb the entire solar spectrum from nearly any angle, the research team has moved academia and industry closer to realizing high-efficiency, cost-effective solar power.

“To get maximum efficiency when converting solar power into electricity, you want a solar panel that can absorb nearly every single photon of light, regardless of the sun’s position in the sky,” said Shawn-Yu Lin, professor of physics at Rensselaer and a member of the university’s Future Chips Constellation, who led the research project. “Our new antireflective coating makes this possible.”

An untreated silicon solar cell only absorbs 67.4 percent of sunlight shone upon it — meaning that nearly one-third of that sunlight is reflected away and thus unharvestable. From an economic and efficiency perspective, this unharvested light is wasted potential and a major barrier hampering the proliferation and widespread adoption of solar power.

After a silicon surface was treated with Lin’s new nanoengineered reflective coating, however, the material absorbed 96.21 percent of sunlight shone upon it — meaning that only 3.79 percent of the sunlight was reflected and unharvested. This huge gain in absorption was consistent across the entire spectrum of sunlight, from UV to visible light and infrared, and moves solar power a significant step forward toward economic viability.

Lin’s new coating also successfully tackles the tricky challenge of angles.

Most surfaces and coatings are designed to absorb light — i.e., be antireflective — and transmit light — i.e., allow the light to pass through it — from a specific range of angles. Eyeglass lenses, for example, will absorb and transmit quite a bit of light from a light source directly in front of them, but those same lenses would absorb and transmit considerably less light if the light source were off to the side or on the wearer’s periphery.

This same is true of conventional solar panels, which is why some industrial solar arrays are mechanized to slowly move throughout the day so their panels are perfectly aligned with the sun’s position in the sky. Without this automated movement, the panels would not be optimally positioned and would therefore absorb less sunlight. The tradeoff for this increased efficiency, however, is the energy needed to power the automation system, the cost of upkeeping this system, and the possibility of errors or misalignment.

Lin’s discovery could antiquate these automated solar arrays, as his antireflective coating absorbs sunlight evenly and equally from all angles. This means that a stationary solar panel treated with the coating would absorb 96.21 percent of sunlight no matter the position of the sun in the sky. So along with significantly better absorption of sunlight, Lin’s discovery could also enable a new generation of stationary, more cost-efficient solar arrays.

“At the beginning of the project, we asked ‘would it be possible to create a single antireflective structure that can work from all angles?’ Then we attacked the problem from a fundamental perspective, tested and fine-tuned our theory, and created a working device,” Lin said. Rensselaer physics graduate student Mei-Ling Kuo played a key role in the investigations.

Typical antireflective coatings are engineered to transmit light of one particular wavelength. Lin’s new coating stacks seven of these layers, one on top of the other, in such a way that each layer enhances the antireflective properties of the layer below it. These additional layers also help to “bend” the flow of sunlight to an angle that augments the coating’s antireflective properties. This means that each layer not only transmits sunlight, it also helps to capture any light that may have otherwise been reflected off of the layers below it.

The seven layers, each with a height of 50 nanometers to 100 nanometers, are made up of silicon dioxide and titanium dioxide nanorods positioned at an oblique angle — each layer looks and functions similar to a dense forest where sunlight is “captured” between the trees. The nanorods were attached to a silicon substrate via chemical vapor disposition, and Lin said the new coating can be affixed to nearly any photovoltaic materials for use in solar cells, including III-V multi-junction and cadmium telluride.

Along with Lin and Kuo, co-authors of the paper include E. Fred Schubert, Wellfleet Senior Constellation Professor of Future Chips at Rensselaer; Research Assistant Professor Jong Kyu Kim; physics graduate student David Poxson; and electrical engineering graduate student Frank Mont.

Funding for the project was provided by the U.S. Department of Energy’s Office of Basic Energy Sciences, as well as the U.S. Air Force Office of Scientific Research.

The Problem With Concentrated Solar Power (CSP)

2010-07-14T15:31:00.002-10:00

The problem with all forms of CSP is that any clouds interfering with direct sunlight causes there to be effectively zero energy conversion, since CSP requires a point source of light like the sun on a clear day. The scattered light available when there is any type of cloud cover comes from many directions and cannot be focused. Such cloud cover can linger for days or even months. On the other hand, flat plate photovoltaic and thermal collectors create useful energy conversion even on a cloudy day. The useful energy conversion in these simple systems is proportional to the light, and do not require direct sunlight nor mechanical tracking with its substantial costs and maintenance issues. With climate change altering cloud cover in many areas, CSP is a risky investment.

Jonathan Cole

Cheap, Energy-efficient Refrigeration

2010-07-14T14:50:00.000-10:00

http://eveningrainfarm.com/2005/08/refrigeration-off-the-grid/

Energy Efficient Refrigeration
by Scott Middlekauff

I used to be among the hordes of off-the-grid homeowners in search of an affordable method of keeping my food cold. My ice chest was affordable, but little else. My tiny propane fridge cost $800, required frequent trips to town for fuel, cost over $200 per year for propane, and it was depressing to be buying fossil fuels. I longed for a Sunfrost, which is efficient, but costs more than my car. Finally, my regular upright fridge tripled my total energy usage. The defrost cycle alone in this an “energy star” fridge used 450 watt/hours per day. 450 watt/hours just to heat my fridge! To top it off, every time I opened it all the cold air spilled out onto my feet. Mine used over double what it was rated, using about 2400 watt/hours per day.

At long last, I think I have discovered the cheapest and most energy efficient refrigeration system. My method costs a bit over $300, and uses about 350 watt/hours of electricity per day. This could run on the equivalent of one 75 watt solar panel.

Basically, I just hooked up a regular chest freezer to a cheap appliance timer.

First, I will assume that you already have an electrical system with an inverter. I don’t know what size inverter that you need to account for the surge, but the compressor uses about 100 watts once it’s running. I would guess that a 600 watt inverter would be plenty of capacity for the surge.

I bought a regular 8.8 cubic foot chest freezer. You could get a bigger one, but I wouldn’t recommend any smaller, because the relative energy efficiency is a bit lower. Then I got a “heavy duty” plug-in appliance timer for $13, a couple of large tupperware containers, and a piece of stiff mesh metal screening (a piece of plywood with holes drilled in it would work fine). A digital thermometer is optional.

The timer needs to be a type with at least three on settings and three off. I chose to set my timer to cycle on for one hour at 9am, one hour at noon, and one hour and a half at 3 pm. The reason for this time schedule is to have the compressor running during times when the sun would normally be shining, so that there will be no strain on the batteries. I also chose to spread out the “on” times as much as possible, so that the fridge doesn’t actually get frozen in the middle of the day, or warm up too much during the night. The compressor cools off the fridge pretty fast, so you wouldn’t want it to be on for much longer than one and a half hours all at once, or else some foods will get a bit frozen.

The thermometer (optional)is to check the temperature in the fridge during the first couple of weeks and adjust the total number of on hours on the timer to get the exact temperature that you want. I feel personally happy with 36-40 degrees. Below 34 risks freezing. At mid 40′s food spoils too fast for me. Based on your personal use, you may need to have your compressor running more, or less, than 3 1/2 hours per day. Our ambient temperature is around 75 degrees.

The stiff metal screening and the tupperware containers have two functions; thermal mass to keep the fridge cool all night, and to raise the bottom of the freezer box so that it is more convenient for people to use. You see, the bottom of the freezer is two different levels; there is a step where the compressor is housed. The result is that most of the freezer box is over 30 inches deep. This is fine for occasional access of typical freezer users, but too awkward for daily usage. So, what I did was fill two large tupperware containers with water (for thermal mass), and place them in the low part of the freezer. To even out the surface so that the entire freezer bottom is at the same level, I placed the stiff metal screening to create a shelf, on top of the two tupperwares. The result is a fridge of about 7 cubic feet, with about 70 pounds of water at the bottom.

If you need the entire 8.8 cubic feet of space, and you want to devise other ways of utilizing the bottom part of the fridge, try it out and let me know how it goes. I would forget about the food way down there, but with properly marked stacked containers, an orderly person could surely have success.

When you first start up the fridge, you will have to leave it on for several extra hours at first, in order to cool off the 70 pounds of water. That’s all. Your fridge is ready to go.

Warning: Don’t insulate a chest freezer. Unlike most refrigerators, the cooling and heat dissipating coils are located all over the walls of the freezer box, so if you add insulation, you will prevent the compressor from getting rid of the heat. The compressor and the food inside will heat up. When the freezer is running, you can verify this by putting your hand on the outside of the freezer; it’s quite warm. An exception on our freezer is the lid. There are no heating or cooling coils on the door. So, actually, I could glue some foam sheeting to the lid with beneficial results. My friend Ann keeps a blanket on top of her freezer.

By the way, this system can be used as a freezer instead of a fridge. I am using one of each. I have been very impressed with the energy efficiency as a fridge, but only moderately impressed with the results as a freezer. The only difference is that I set the timer for the freezer to turn it “on” at 8am, “off” at 6pm and then “on” again around midnight for an hour. Normally, freezers keep a temperature of about 5 degrees. I keep it running for a total of 11 hours per day, and this keeps the temperature at about 15 degrees. With this temperature, very sweet things like frozen fruit are sometimes a bit soft, though ice cubes maintain their integrity. I accurately monitored the temperature inside my freezer by leaving a jar of sand inside.

I use a timer for my freezer for two reasons: First, freezers normally keep a temperature of about 5 degrees, and I found that about 15 degrees keeps food frozen enough. Second, this way, the compressor only runs during sunlight hours, instead of responding to the thermostat. The total energy usage for our freezer is about 1100 watt/hours per day, which is a pretty big chunk of energy on a solar system.

Based on my (incomplete) research, the only other truly energy efficient refrigeration available seems to be the Sunfrost. Unfortunately, I have heard bad things about their plywood construction, tendency for coolant leaks, poor customer service, and super high prices ($2000+). The Conserve chest freezer is probably great, but their stand-up fridge is an energy hog and costs over $900. I couldn’t find anything else really enticing. So there it is.

Addendum, three years later:
Where I live, the high humidity causes many electronic items to cease working in short order. For example, in four years we have been through four printers, half dozen telephones, over a dozen flashlights (high quality brands), and countless other plugs, fittings, light sockets, and adaptors. We have also thrown away five of the “heavy duty” appliance timers used on our 3 freezer/fridges. They are rated for 1,500 watts, and I’ve measured the running power consumption at under 100 watts. I have no way of measuring the surge, though I guess it is somewhere around 300-500 watts. In any case, after a year of trouble-free operation, these timers sometimes fail to turn the fridge on and sometimes fail to turn it off. My guess is that the contact points on the switch are becoming corroded, though that leaves me confused about the failure to turn it off. I’m curious if other people have had this experience.

In any case, we recently purchased some digital water heater timers. They need to be hard wired, rather than just plugged in. I wired male and female plugs onto ours. These timers are rated at 30 amps, and they cost around $70. Hopefully, this will solve the problem.

2009-12-05T07:15:00.004-10:00

Make Solar Energy Work for You!!
My New Book Will Light the Way.
Light On the Earth: The Solar Option
By Jonathan R. Cole
Get it at http://www.lightontheearth.org/

Based on Jonathan Cole's 27 years of experience in designing, building and living with solar energy systems, this book, in clear, concise language, spells out the path to successfully utilizing solar energy to supply your energy needs. Reading this will enable you and/or your contractor/installer to build a low-maintenance, cost-effective solar energy system that you can rely on for decades.

The dramatic, pressing need to get people to start taking individual responsibility for their energy-use habits has now reached a critical point. The quality of life of all future generations is hanging in the balance. We must change the way we use energy.

Light on the Earth: The Solar Option provides the knowledge and actions required to help reverse the dire consequences of the many unintended side-effects of the industrial revolution. From efficiency to low-waste strategies culminating in affordable, clean energy generation from the sun, the path to a bright clean world is within your reach.

No longer just a trendy subject matter for cocktail parties, sustainable living must be a strategy we adopt as a society to avoid a grim future of increasing poverty, collapsing health, social disintegration and the extinction of the biosphere. We are at the tipping point right now. The political process, too often in the pocket of industry will be glacial in changing our current course. We don't have the time - the people must vote with their pocketbooks and personal lifestyle choices,

Light On The Earth: The Solar Option is the first step on the way to a clean, green energy conscience while maintaining a high standard of living. and it can recoup its purchase price many times over.

Solar Workshop Notes

2009-05-15T14:25:00.001-10:00

Light On The Earth

The Solar Option

Can We Live Lightly on the Earth?

• Combustion of fuel and depletion of resources are the foundation of our economic prosperity and high standard of living.

• The Industrial Revolution - A cauldron of unintended chemistry and the decimation of the natural world.

• Can we have prosperity and a high standard of living some other way?

• Yes, if we want to, we have the technology to live in balance with the eco-system.

• The only question is:

Are we capable of changing our habits to preserve the natural world and to have enduring prosperity?

That is our Choice.

The Solar Option
We have light on the earth.
Let’s use it.

With up to a 40 year life, solar-electric panels are the most durable, low maintenance and reliable technology ever devised by man.
And with no moving parts!!

How many products in your house have a 25 year warranty?
Solar-electric panels do.

But, Isn’t it too expensive?

• Not if we design the systems wisely!

• The system I live on cost less than the price of a three year old, used economy car.

• Yet I have all of the modern amenities.

• I expect the system to last up to 40 years.

• I expect far greater reliability than the power grid.

• Energy security is a side benefit.

What are the three pillars of a practical solar energy system?

• Efficient equipment

• Low-waste strategies

• Solar energy technology

Why Efficient Equipment?

• Constant efficiency improvements in energy-using equipment allows us to get the desired result with ever smaller energy use.

• Appliances, lighting fixtures, tools and systems can use a large or small amount of energy to perform the same function. Of course less is better!

• Added bonus: as a rule, the less energy an appliance uses, the longer it will last.

• The less energy you need the smaller and less expensive your solar energy system will be.

Low Waste Strategies

• Our waste of energy must come to an end.

• We may be wasting as much as 50% of the energy we use.

• Leaving energy appliances running when they are not being used cannot be tolerated. This means participation by every person in the household and the use of switches and timers to prevent waste of energy.

• A change in habits is a small price to assure the health of the natural world!!!

Reduce energy use through Efficiency

Products are labeled with their energy use

• Specified in watts

• Specified in watts/unit time

• Specified in voltage and amps which can be multiplied to approximate watts

• Can be directly measured during use with a Kill-a-watt meter

Calculating energy efficiency

• If you start with a given amount of energy, efficiency describes what percentage of the energy actually performs the desired function and what part is wasted.

• If an appliance is 80% efficient that means that 20% is wasted.

• In a calculation you can multiply by .80 in order to get 80%.

• For instance, a refrigerator of 20 cubic feet that requires 1000 watt/hours per day is more efficient than a 20 cubic foot model that requires 2000 watt/hours per day.

• The first model requires:

1000wHr / 20 cf =50 wHr/cf/day

The second model requires:

2000wHr / 20 cf =100 wHr/cf/day

What is a solar energy system?

• Electrical generation using solid-state (no moving parts) photovoltaics with solid-state electronic conditioning devices and electrical energy storage

• Thermal Solar (heating) devices to heat water and air, to dry clothes and foods, as well as cooling by evaporation.

• Solar technology can reduce the use of polluting forms of energy use by 80-95%.

How to reduce energy requirements

• 1. Efficient equipment

• 2. Reduce waste by use of switches, timers and a frugal energy ethic.

• 3. Reduce energy use procedures starting with the most energy intensive appliances.

The Order of Energy Intensivity

1. Space heating and cooling (furnace/air conditioning)

2. Water heating

3. Refrigeration

4. Water pumping (where applicable)

5. Washer and dryer

6. Lighting

7. TV

8. Power Tools (occasional use)

9. Desktop Computers; Laptop computers; Printers/scanners

10. Microwave (occasional use); Cooking

11. Small electronic devices (cordless phones, rechargeable digital cameras, cell phones, etc)

Energy type in order of value

• Electrical Energy – Has a higher cost to obtain but is more useful because of its speed of transmission and ease and length of storage. It can be converted to a wide range of uses.

• Heat Energy (below the boiling point) is more readily available and easily collected but it dissipates rapidly. It is not economically convertible to electricity.

Solar heating and cooling utilizing passive solar and ventilation

Insulation, calking and ventilation

• These are cost-effective ways to reduce the amount of energy needed from expensive active equipment.

• Double or triple glazed windows reduce heat transfer through window glass.

• Insulation in roof floor and walls minimize heat loss or buildup.

• Calking reduces drafts and leakage of heat.

• Ventilation adds temperature control as it allows cool air to be pulled in down low as heat is expelled up high.

• Active or automated ventilation utilizes sensors, fans and mechanized closures and allows heating and cooling functions to be controlled without human input.

Water heating

• The biggest bang for your buck!

• On average the 2^nd biggest energy user in your household.

• Normal hot water systems use one component – a heater/tank utilizing electricity or gas to heat the water.

• A solar hot water system adds a few components to dramatically reduce energy cost. Thus there is a rapid payback.

What about cloudy weather?

• Solar energy creates heat when light strikes a dark surface. Higher energy visible wavelength excites the dark surface which then radiates a lower frequency, non-visible light called infrared. Infrared is heat.

• A hot water system is sized for cloudy conditions. Since solar does not always provide enough, a practical system also uses backup in the form of electric or gas.

The simplest system is best.

• Roof or ground mount?

• Pump or thermo-siphon (uses no pump)?

• Proximity to point of use.

• Type of backup

Flat plate collector

• The simplest and most economical form of solar water heater.

Thermo-siphon system

• The simplest, most elegant design.

The most durable and efficient system

• Ground mount gives easy access for occasional cleaning

• Allows close proximity to point of use

• Allows a simple thermo-siphon system with no pump to break down.

• Less plumbing, means less costly installation and no holes in the roof to leak.

Backup system

• Instantaneous hot water heater is the best.

• Solar acts as a pre-heater reducing energy use.

• Extremely cost effective.

Heating air with solar energy

• Very cost effective

• Simplest form of collector

• Heat living space or the intake air to a clothes dryer.

Passive heating

• Allow the house to be the solar collector.

Refrigeration

• After hot water, it is usually biggest energy user.

• Keep refrigerator in a cool place!!!

• Use Energy Star Appliances for best performance to cost ratio.

• Use a 20 Amp appliance timer on your fridge for reduced energy use.

• Avoid high-cost solar specialty refrigerators. They cost too much and are harder to get repaired.

• Keep it full to store the cold.

Water Pumping

• Uses quite a bit of energy per unit time.

• Pressurizing water pumps are only used when water is running and so use less.

• Washing machines use pumps which partially accounts for their relatively high energy use.

• Small pumps like those for aquariums use relatively small amounts of electricity but are sometimes on 24/7, so it adds up.

Washer and dryer

• Laundry equipment is fairly energy intensive.

• Use Energy Star appliances

• Use liquid detergents, cold water and short wash cycles for most applications.

• Use a solar assisted gas dryer in a solar electric house.

Lighting

• Use compact fluorescent or LED lights whenever possible. Use compact fluorescent bulbs that have globes to avoid mercury contamination.

• Avoid lights that are hot to the touch. This indicates low efficiency.

• Do not leave lights on when they are not required.

Energy consumption of light bulbs

Television

• The larger the set the more electricity it uses.

• A 32 inch LCD flat screen TV uses about 100 watts

• A 24 inch model uses 60 watts.

• Standby mode uses a lot of energy.

• Eliminate these parasitic losses with a switchable power strip.

Power Tools

• My solar energy system has no problem handling the occasional use of power tools.

• Table saw, circular saw, chop saw, drill, rechargeable tools, sanders all operate without a problem.

• Same is true of most kitchen appliances.

Computers and printer/scanners

• Laptops use much less energy than desktops.

• My laptop uses about 20 watts compared to up to 250 watts/hr for a desktop computer.

• Some larger laptops use up to 90 watts/hr.

• Printers/scanners use a very small amount of electricity. But they have standby energy use. Use a power strip to completely shut it down when not in use.

Desktop vs. Laptop

• Based on two hours use per day:

• Annual Desktop energy usage: 500wHr x 365 days/year = 182.5 kwHr/year

• Annual Laptop energy usage: 180wHr x 365 days/year = 65.7 kwHr/year

• Energy Savings by using a laptop 182.5 kwHr – 65.7 kwHr = 116.8 kwHr/year

• By reducing your use 116.8 kwHr/year you require approximately 90 watts less of solar generating capacity. At about $8.00/watt installed, this amounts to $720 less solar generating equipment.

Small appliances

• All work well with solar since their use is occasional and total energy use is low over time.

The Photovoltaic (PV) Electrical Generation System

• Electricity generated from light

• Proportional to the amount of light

• 1000 watts/square meter on a sunny day

• PV panels are from 15-22% efficient

• Crystalline and multi-crystalline varieties

Photovoltaic Panels

• The best have a 25 year power warranty

• The most durable active product devised by man with an expected life of up to 40 years

• 100-300 peak watts per panel

• High-watt panels are physically larger but heavier and harder to handle

• Smaller panels are easier to handle but require more connections and more installation expense

System Types

• If your system is connected to the power grid and can sell power to the electric company it is called a grid-tied system.

• If your system does not sell power to the grid but is independent or is connected but only uses the grid power as backup, it is called an independent system.

• A hybrid system has elements of both types

Grid-tied vs. Independent System

Grid-Tied Components

Independent System Components

The difference between the two types of system

• Batteries

• Used properly they have 90%+ efficiency and a 10-15 year life.

What to expect from batteries

• As an example, I paid $1200 for my batteries that give me 5-10 KwHr of storage at 90% efficiency.

• I expect them to last at least 10 years. That is a cost of about $10 per month.

• There are new batteries in development with 1/10th the weight, 1/5th the cost per kwHr and that could last up to 40 years. They have a claimed 95% throughput efficiency and are completely no-maintenance and environmentally friendly.

• By the time your first set of lead-acid batteries is used up, these new types should be available.

• Batteries require periodic addition of distilled water.

Direct Current (DC) vs. Alternating Current (AC)

• Normal household current is AC

• DC is generally used in boats and recreational vehicles and is stored in batteries

• AC appliances are more durable and readily available

• The inverter changes the DC from your panels into AC for your house.

How much energy is available from the sun?

Variation during the day

Average Annual Variation

Average retail price per peak watt of PV panels

Panel rating

• PV panels are sized to their peak output capacity.

• On a clear day at noon, if the panel is perpendicular to the sun’s rays, it should put out an amount in watts that is very close to the rated output of the panel.

• The actual output varies with panel mounting angle, cloud cover and time of year (length of day)

How panels are mounted

• Fixed-angle, roof Mount

How panels are mounted

• Fixed-angle, ground mount

How panels are mounted

• Sun-tracking, ground mount

The best mounting system

• Panels and all other components mounted together

Benefits of mounting everything in one location

• Lower cost of wiring and less losses in the wiring

• Ease of access and maintenance

• Ease of access reduces cost of repairs

• Ease of maintenance reduces cost of maintenance making it more likely

• Safer

• Lower overall installation cost

• Does not interfere with or penetrate house roofing system

Maintenance issues

• All solar panels must be cleaned on a regular basis. At least every 3 months. Don’t believe anyone who says they are self cleaning!!

• This means using a soft broom to clean the surface and rinsing with water. Not so easy if the panels are on an inaccessible roof.

Maintenance issues, cont’d

• Not so easy to clean or inspect if panels are put together in a huge array with no space between panels for access.

Maintenance, cont’d

• If you must roof mount, something like this makes more sense.

The problem with roof mounting

• The fasteners that penetrate the roof are a cause of possible roof leaks (40 years is a long time).

• To replace the roofing will require the complete dismounting of your solar panels.

• In the event of a house fire the firemen wanting to make an opening in your roof to save the house make have to destroy your solar panels.

• Cleaning and repairs are more difficult on the roof.

Designing system for long life

• Photovoltaic systems last 30-40 years

• Any system with that kind of life expectancy must be designed for ease of use, low cost of maintenance and repairs

• An improperly designed or installed system can cause what should be a trouble-free technology to become just the opposite

Monitoring your independent system

• In normal use, you only need to monitor one number, the DC voltage.

• This meter must be mounted in a highly visible location like the kitchen

What type of meter?

• LED meter with 3/4 to 1 inch numerals

• Mounted in central location such as the kitchen

• Always visible even in the dark

• Two digits to the left of the decimal point gives the range of sensitivity necessary

• By observing how this number responds to energy use you will learn how your system works and will have early warning of any malfunctions

Monitoring Grid-tied systems

• The best monitoring system for grid-tied applications is an internet based system that comes with the EnPhase micro-inverter system. http://www.enphaseenergy.com/products/products/micro-inverter.cfm

• One inverter per panel allows remote monitoring and assessment of each panel’s performance over time. This maximizes the output of your panels.

• Micro-inverters generally have a longer life expectancy due to minimal heat dissipation.

• Other inverter systems may have similar monitoring systems.

Charge controllers

• These devices control the output of the PV panels.

• On an independent system they control the charging of the batteries and include multiple monitoring functions.

• On grid-tied systems they are included as a part of the inverter and maximize the power obtained from the panels.

Inverters and inverter/chargers

• Inverters are electronic devices that change Direct Current (DC) electricity into Alternating Current (AC) electricity.

• Life expectancy is 10-20 years

• Warranties are from 2-10 years

Inverter specifications

• Continuous output in watts

• Short-term surge capacity

• Input (DC) voltage

• Efficiency

• True Sine Wave or Quasi-Sine wave

• Company reliability in the marketplace

• Monitoring and trouble shooting features

Backup For Independent Systems

• Use the grid with a battery charger (least expensive if you are already connected).

• Use a generator in an enclosure with an inverter/charger.

• Automated vs. Manual operation

Using Peak Sun Hours to Size Your System

• Peak sun energy occurs between 11:30 AM and 12:30 PM on a cloudless day. This is one peak sun hour.

• The annual average daily number of peak sun hours is different in each location depending on latitude, cloud cover and elevation.

• This information is available on charts and allows estimates of expected energy availability for sizing a solar system.

Variables

• You can further refine this chart by estimating your energy-use habits. If you are careful in the way you use energy, these figures will work well. If you are an average householder, you can add 15% to these figures. If you don’t pay any attention to how you use energy, then you can double these estimated system costs.

• Which demonstrates conclusively why energy efficiency and low-waste strategies can pay off in a big way.

Additional Benefits

• These estimates of cost do not include the tax credits available from State and Federal government.

• Tax benefits can reduce the overall cost of the system by 30% or more. U.S. Tax incentives can be found here:

• http://www.dsireusa.org/

• Independent systems provide energy security in the form of uninterruptible power.

Internet Resources

• http://www.solar-nation.org/

• http://www.homepower.com/home/

• http://www.renewableenergyworld.com/rea/home

• http://lightontheearth.blogspot.com/

Major Breakthrough for Photovoltaics Technology

2008-11-04T07:29:00.001-10:00

Solar Power Game-changer: 'Near Perfect' Absorption Of Sunlight, From All Angles

A new antireflective coating developed by researchers at Rensselaer could help to overcome two major hurdles blocking the progress and wider use of solar power. The nanoengineered coating, pictured here, boosts the amount of sunlight captured by solar panels and allows those panels to absorb the entire spectrum of sunlight from any angle, regardless of the sun's position in the sky. (Credit: Rensselaer/Shawn Lin)

ScienceDaily (Nov. 4, 2008) — Researchers at Rensselaer Polytechnic Institute have discovered and demonstrated a new method for overcoming two major hurdles facing solar energy. By developing a new antireflective coating that boosts the amount of sunlight captured by solar panels and allows those panels to absorb the entire solar spectrum from nearly any angle, the research team has moved academia and industry closer to realizing high-efficiency, cost-effective solar power.

“To get maximum efficiency when converting solar power into electricity, you want a solar panel that can absorb nearly every single photon of light, regardless of the sun’s position in the sky,” said Shawn-Yu Lin, professor of physics at Rensselaer and a member of the university’s Future Chips Constellation, who led the research project. “Our new antireflective coating makes this possible.”

An untreated silicon solar cell only absorbs 67.4 percent of sunlight shone upon it — meaning that nearly one-third of that sunlight is reflected away and thus unharvestable. From an economic and efficiency perspective, this unharvested light is wasted potential and a major barrier hampering the proliferation and widespread adoption of solar power.

After a silicon surface was treated with Lin’s new nanoengineered reflective coating, however, the material absorbed 96.21 percent of sunlight shone upon it — meaning that only 3.79 percent of the sunlight was reflected and unharvested. This huge gain in absorption was consistent across the entire spectrum of sunlight, from UV to visible light and infrared, and moves solar power a significant step forward toward economic viability.

Lin’s new coating also successfully tackles the tricky challenge of angles.

Most surfaces and coatings are designed to absorb light — i.e., be antireflective — and transmit light — i.e., allow the light to pass through it — from a specific range of angles. Eyeglass lenses, for example, will absorb and transmit quite a bit of light from a light source directly in front of them, but those same lenses would absorb and transmit considerably less light if the light source were off to the side or on the wearer’s periphery.

This same is true of conventional solar panels, which is why some industrial solar arrays are mechanized to slowly move throughout the day so their panels are perfectly aligned with the sun’s position in the sky. Without this automated movement, the panels would not be optimally positioned and would therefore absorb less sunlight. The tradeoff for this increased efficiency, however, is the energy needed to power the automation system, the cost of upkeeping this system, and the possibility of errors or misalignment.

Lin’s discovery could antiquate these automated solar arrays, as his antireflective coating absorbs sunlight evenly and equally from all angles. This means that a stationary solar panel treated with the coating would absorb 96.21 percent of sunlight no matter the position of the sun in the sky. So along with significantly better absorption of sunlight, Lin’s discovery could also enable a new generation of stationary, more cost-efficient solar arrays.

“At the beginning of the project, we asked ‘would it be possible to create a single antireflective structure that can work from all angles?’ Then we attacked the problem from a fundamental perspective, tested and fine-tuned our theory, and created a working device,” Lin said. Rensselaer physics graduate student Mei-Ling Kuo played a key role in the investigations.

Typical antireflective coatings are engineered to transmit light of one particular wavelength. Lin’s new coating stacks seven of these layers, one on top of the other, in such a way that each layer enhances the antireflective properties of the layer below it. These additional layers also help to “bend” the flow of sunlight to an angle that augments the coating’s antireflective properties. This means that each layer not only transmits sunlight, it also helps to capture any light that may have otherwise been reflected off of the layers below it.

The seven layers, each with a height of 50 nanometers to 100 nanometers, are made up of silicon dioxide and titanium dioxide nanorods positioned at an oblique angle — each layer looks and functions similar to a dense forest where sunlight is “captured” between the trees. The nanorods were attached to a silicon substrate via chemical vapor disposition, and Lin said the new coating can be affixed to nearly any photovoltaic materials for use in solar cells, including III-V multi-junction and cadmium telluride.

Along with Lin and Kuo, co-authors of the paper include E. Fred Schubert, Wellfleet Senior Constellation Professor of Future Chips at Rensselaer; Research Assistant Professor Jong Kyu Kim; physics graduate student David Poxson; and electrical engineering graduate student Frank Mont.

Funding for the project was provided by the U.S. Department of Energy’s Office of Basic Energy Sciences, as well as the U.S. Air Force Office of Scientific Research.

Journal reference:

Kuo et al. Realization of a near-perfect antireflection coating for silicon solar energy utilization. Optics Letters, 2008; 33 (21): 2527 DOI: 10.1364/OL.33.002527

Adapted from materials provided by Rensselaer Polytechnic Institute.

Renewable Energy Action Agenda

2008-09-04T07:49:00.000-10:00

Renewable Energy Action Agenda

It would be interesting if each of the 'experts' making commentary about various renewable energy options were to actually state if they have any actual experience beyond the theoretical. There are actually not many people who are utilizing renewable energy in their every-day lives outside of perhaps solar hot water heating. Those of us who have been using these technologies for decades are often bemused but frustrated by the obvious misrepresentations about cost, utility, user-friendliness and affordability that frequently arise in these commentaries.

At first I thought it was people with vested interest in the old technologies, but I think that is just a part of the problem. There also seem to be a subset of people trying to create an identity for themselves by venturing opinions on subjects that they have no first-hand knowledge of. They can often be identified by how sure they are of themselves.

We need to get over these kinds of competitive debates. We need to get to work to bring technologies that work to the market. We need less 'experts' and more entrepreneurs and visionary investors. These problems are not going to be solved by venture capitalist slight of hand nor those 'experts who can deconstruct anything. The technologies that already overwhelm the world are riddled with problems that make them improbable successes. Just because we can identify problems does not mean we should abandon the effort to develop technologies that overcome the problems. The alternative is mass extinction, including, possibly, of the human race.

Jonathan Cole

First things first

2008-09-03T08:53:00.001-10:00

To the numerous people who have pointed out that we need to let the market determine which technologies win - That is a great idea in an idealized world where the government does not get paid by giant corporations to pass legislation that mandates their products and creates very high barriers to entry by any competing technologies. The fact is we cannot fix these problems if we don't end corrupt practices of government and industry that disable the healthy functioning of the market. And that problem is much bigger than symptoms like climate change, air pollution and eco-tastrophe. Why? Because most people don't get it and the ones that do are the ones who are doing it!
http://lightontheearth.blogspot.com/2008/07/light-on-earth-manual-for-global.html
Jonathan Cole, MBA

Al Gore is Under-reaching

2008-07-25T08:39:00.001-10:00

The Sands of Denial

I note with interest how simple it is to take simple ideas and recount a thousand technical reasons why they cannot possibly work. I think Al Gore has made a mistake in the approach he is taking to the problems facing the world. He is under-reaching.

By closely coupling the crisis to global warming, he gives critics an easy target for slander. The fact is that the natural workings of the climate are so complex, that greenhouse gases in combination with fewer sunspots, more or less particulate matter in the atmosphere, melting ice, changing currents, etc., can push the climate toward warming or cooling under different circumstances and in different time frames.

However, the crisis of the widespread contamination of the natural world is not simply an issue of climate change. The unintended consequences of the combustion-based industrial revolution are a cauldron of unintended chemistry in the land, sea and air. The rapid rate of this change makes it difficult for many biological organisms to adapt and thus we are in an age of mass extinction caused in large part by the way we provide for our standard of living. There is some reason to suspect that human beings may not be exempt from this extinction trend.

So while some people like to show how smart they are by tearing down people like Al Gore, I suggest that, instead we work together to insure the survival of a habitable planet and a decent standard of living. With non-combustion renewable energy, elimination of waste, increase of efficiency and a more responsible attitude toward stewardship of the planet, we may yet make it through this serious crisis and come out stronger, richer, healthier and happier than if we stick our heads in the sand of denial.

Major solar breakthrough!?

2008-07-11T07:18:00.004-10:00

New 'Window' Opens On Solar Energy: Cost Effective Devices Available Soon

ScienceDaily (July 11, 2008) — Imagine windows that not only provide a clear view and illuminate rooms, but also use sunlight to efficiently help power the building they are part of. MIT engineers report a new approach to harnessing the sun's energy that could allow just that.

The work, reported in the July 11 issue of Science, involves the creation of a novel "solar concentrator." "Light is collected over a large area [like a window] and gathered, or concentrated, at the edges," explains Marc A. Baldo, leader of the work and the Esther and Harold E. Edgerton Career Development Associate Professor of Electrical Engineering.

As a result, rather than covering a roof with expensive solar cells (the semiconductor devices that transform sunlight into electricity), the cells only need to be around the edges of a flat glass panel. In addition, the focused light increases the electrical power obtained from each solar cell "by a factor of over 40," Baldo says.

Because the system is simple to manufacture, the team believes that it could be implemented within three years--even added onto existing solar-panel systems to increase their efficiency by 50 percent for minimal additional cost. That, in turn, would substantially reduce the cost of solar electricity.

In addition to Baldo, the researchers involved are Michael Currie, Jon Mapel, and Timothy Heidel, all graduate students in the Department of Electrical Engineering and Computer Science, and Shalom Goffri, a postdoctoral associate in MIT's Research Laboratory of Electronics.

"Professor Baldo's project utilizes innovative design to achieve superior solar conversion without optical tracking," says Dr. Aravinda Kini, program manager in the Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science, a sponsor of the work. "This accomplishment demonstrates the critical importance of innovative basic research in bringing about revolutionary advances in solar energy utilization in a cost-effective manner."

Solar concentrators in use today "track the sun to generate high optical intensities, often by using large mobile mirrors that are expensive to deploy and maintain," Baldo and colleagues write in Science. Further, "solar cells at the focal point of the mirrors must be cooled, and the entire assembly wastes space around the perimeter to avoid shadowing neighboring concentrators."

The MIT solar concentrator involves a mixture of two or more dyes that is essentially painted onto a pane of glass or plastic. The dyes work together to absorb light across a range of wavelengths, which is then re-emitted at a different wavelength and transported across the pane to waiting solar cells at the edges.

In the 1970s, similar solar concentrators were developed by impregnating dyes in plastic. But the idea was abandoned because, among other things, not enough of the collected light could reach the edges of the concentrator. Much of it was lost en route.

The MIT engineers, experts in optical techniques developed for lasers and organic light-emitting diodes, realized that perhaps those same advances could be applied to solar concentrators. The result? A mixture of dyes in specific ratios, applied only to the surface of the glass, that allows some level of control over light absorption and emission. "We made it so the light can travel a much longer distance," Mapel says. "We were able to substantially reduce light transport losses, resulting in a tenfold increase in the amount of power converted by the solar cells."

This work was also supported by the National Science Foundation. Baldo is also affiliated with MIT's Research Laboratory of Electronics, Microsystems Technology Laboratories, and Institute for Soldier Nanotechnologies.

Mapel, Currie and Goffri are starting a company, Covalent Solar, to develop and commercialize the new technology. Earlier this year Covalent Solar won two prizes in the MIT $100K Entrepreneurship Competition. The company placed first in the Energy category ($20,000) and won the Audience Judging Award ($10,000), voted on by all who attended the awards.

http://www.sciencedaily.com/releases/2008/07/080710142927.htm

Adapted from materials provided by Massachusetts Institute of Technology.

Light on the Earth

EIA of Geothermal Projects in Iceland

ABSTRACT

Isaksson, K., T. Richardson and K. Olsson, 2009. From

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Light On The Earth

The Solar Option

Can We Live Lightly on the Earth?

• Combustion of fuel and depletion of resources are the foundation of our economic prosperity and high standard of living.

• The Industrial Revolution - A cauldron of unintended chemistry and the decimation of the natural world.

• Can we have prosperity and a high standard of living some other way?

• Yes, if we want to, we have the technology to live in balance with the eco-system.

• The only question is:

Are we capable of changing our habits to preserve the natural world and to have enduring prosperity? That is our Choice.

The Solar OptionWe have light on the earth.Let’s use it.

With up to a 40 year life, solar-electric panels are the most durable, low maintenance and reliable technology ever devised by man.And with no moving parts!!

How many products in your house have a 25 year warranty?Solar-electric panels do.

But, Isn’t it too expensive?

• Not if we design the systems wisely!

• The system I live on cost less than the price of a three year old, used economy car.

• Yet I have all of the modern amenities.

• I expect the system to last up to 40 years.

• I expect far greater reliability than the power grid.

• Energy security is a side benefit.

What are the three pillars of a practical solar energy system?

• Efficient equipment

• Low-waste strategies

• Solar energy technology

Why Efficient Equipment?

• Constant efficiency improvements in energy-using equipment allows us to get the desired result with ever smaller energy use.

• Appliances, lighting fixtures, tools and systems can use a large or small amount of energy to perform the same function. Of course less is better!

• Added bonus: as a rule, the less energy an appliance uses, the longer it will last.

• The less energy you need the smaller and less expensive your solar energy system will be.

Low Waste Strategies

• Our waste of energy must come to an end.

• We may be wasting as much as 50% of the energy we use.

• Leaving energy appliances running when they are not being used cannot be tolerated. This means participation by every person in the household and the use of switches and timers to prevent waste of energy.

• A change in habits is a small price to assure the health of the natural world!!!

Reduce energy use through Efficiency

Products are labeled with their energy use

• Specified in watts

• Specified in watts/unit time

• Specified in voltage and amps which can be multiplied to approximate watts

• Can be directly measured during use with a Kill-a-watt meter

Calculating energy efficiency

• If you start with a given amount of energy, efficiency describes what percentage of the energy actually performs the desired function and what part is wasted.

• If an appliance is 80% efficient that means that 20% is wasted.

• In a calculation you can multiply by .80 in order to get 80%.

• For instance, a refrigerator of 20 cubic feet that requires 1000 watt/hours per day is more efficient than a 20 cubic foot model that requires 2000 watt/hours per day.

• The first model requires:

1000wHr / 20 cf =50 wHr/cf/day

The second model requires:

2000wHr / 20 cf =100 wHr/cf/day

What is a solar energy system?

Are we capable of changing our habits to preserve the natural world and to have enduring prosperity?

That is our Choice.

The Solar Option
We have light on the earth.
Let’s use it.

With up to a 40 year life, solar-electric panels are the most durable, low maintenance and reliable technology ever devised by man.
And with no moving parts!!

How many products in your house have a 25 year warranty?
Solar-electric panels do.

• On average the 2^nd biggest energy user in your household.