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Friday, December 7, 2012

Major Breakthrough - The Photon Trap

Princeton researchers have found a simple and economical way to nearly triple the efficiency of organic solar cells, the cheap and flexible plastic devices that many scientists believe could be the future of solar power. (Credit: Image courtesy of Princeton University, Engineering School) 
ScienceDaily (Dec. 6, 2012) — Princeton researchers have found a simple and economical way to nearly triple the efficiency of organic solar cells, the cheap and flexible plastic devices that many scientists believe could be the future of solar power.

The researchers, led by electrical engineer Stephen Chou, were able to increase the efficiency of the solar cells 175 percent by using a nanostructured "sandwich" of metal and plastic that collects and traps light. Chou said the technology also should increase the efficiency of conventional inorganic solar collectors, such as standard silicon solar panels, although he cautioned that his team has not yet completed research with inorganic devices.
Chou, the Joseph C. Elgin Professor of Engineering, said the research team used nanotechnology to overcome two primary challenges that cause solar cells to lose energy: light reflecting from the cell, and the inability to fully capture light that enters the cell.
With their new metallic sandwich, the researchers were able to address both problems. The sandwich -- called a subwavelength plasmonic cavity -- has an extraordinary ability to dampen reflection and trap light. The new technique allowed Chou's team to create a solar cell that only reflects about 4 percent of light and absorbs as much as 96 percent. It demonstrates 52 percent higher efficiency in converting light to electrical energy than a conventional solar cell.
That is for direct sunlight. The structure achieves even more efficiency for light that strikes the solar cell at large angles, which occurs on cloudy days or when the cell is not directly facing the sun. By capturing these angled rays, the new structure boosts efficiency by an additional 81 percent, leading to the 175 percent total increase.
Chou said the system is ready for commercial use although, as with any new product, there will be a transition period in moving from the lab to mass production.
The physics behind the innovation is formidably complex. But the device structure, in concept, is fairly simple.
The top layer, known as the window layer, of the new solar cell uses an incredibly fine metal mesh: the metal is 30 nanometers thick, and each hole is 175 nanometers in diameter and 25 nanometers apart. (A nanometer is a billionth of a meter and about one hundred-thousandth the width of human hair). This mesh replaces the conventional window layer typically made of a material called indium-tin-oxide (ITO).
The mesh window layer is placed very close to the bottom layer of the sandwich, the same metal film used in conventional solar cells. In between the two metal sheets is a thin strip of semiconducting material used in solar panels. It can be any type -- silicon, plastic or gallium arsenide -- although Chou's team used an 85-nanometer-thick plastic.
The solar cell's features -- the spacing of the mesh, the thickness of the sandwich, the diameter of the holes -- are all smaller than the wavelength of the light being collected. This is critical because light behaves in very unusual ways in subwavelength structures. Chou's team discovered that using these subwavelength structures allowed them to create a trap in which light enters, with almost no reflection, and does not leave.
"It is like a black hole for light," Chou said. "It traps it."
The team calls the system a "plasmonic cavity with subwavelength hole array" or PlaCSH. Photos of the surface of the PlaCSH solar cells demonstrate this light-absorbing effect: under sunlight, a standard solar power cell looks tinted in color due to light reflecting from its surface, but the PlaCSH looks deep black because of the extremely low light reflection.
The researchers expected an increase in efficiency from the technique, "but clearly the increase we found was beyond our expectations," Chou said.
Chou and electrical engineering graduate student Wei Ding reported their findings in the journal Optics Express, published online Nov. 2, 2012. Their work was supported in part by the Defense Advanced Research Projects Agency, the Office of Naval Research and the National Science Foundation.
The researchers said the PlaCSH solar cells can be manufactured cost-effectively in wallpaper-size sheets. Chou's lab used "nanoimprint," a low-cost nanofabrication technique Chou invented 16 years ago, which embosses nanostructures over a large area, like printing a newspaper.
Besides the innovative design, the work involved optimizing the system. Getting the structure exactly right "is critical to achieving high efficiency," Ding said.
Chou said that the development could have a number of applications depending on the type of solar collector. In this series of experiments, Chou and Ding worked with solar cells made from plastic, called organic solar cells. Plastic is cheap and malleable and the technology has great promise, but it has been limited in commercial use because of organic solar cells' low efficiency.
In addition to a direct boost to the cells' efficiency, the new nanostructured metal film also replaces the current ITO electrode that is the most expensive part of most current organic solar cells.
"PlaCSH also is extremely bendable," Chou said. "The mechanical property of ITO is like glass; it is very brittle."
The nanostructured metal film is also promising for silicon solar panels that now dominate the market. Because the PlaCSH sandwich captures light independent of what electricity-generating material is used as the middle layer, it should boost efficiency of silicon panels as well. It also can reduce the thickness of the silicon used in traditional silicon solar panels by a thousand-fold, which could substantially decrease manufacturing costs and allow the panels to become more flexible.
Chou said the team plans further experiments and expects to increase the efficiency of the PlaCSH system as they refine the technology.

Story Source:
The above story is reprinted from materials provided by Princeton University, Engineering School. The original article was written by John Sullivan.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. Stephen Y. Chou, Wei Ding. Ultrathin, high-efficiency, broad-band, omni-acceptance, organic solar cells enhanced by plasmonic cavity with subwavelength hole array. Optics Express, 2012; 21 (S1): A60 DOI: 10.1364/OE.21.000A60

Princeton University, Engineering School (2012, December 6). Tiny structure gives big boost to solar power. ScienceDaily. Retrieved December 7, 2012, from­ /releases/2012/12/121206203419.htm
Note: If no author is given, the source is cited instead.

Wednesday, October 3, 2012

Distributed Solar Beats Centralized Solar

Comments following the DOE PEIS “discussion” in Kona, HI, 13 Sept 2012.   

A vote for more support for environmentally benign home solar energy
Ulrich Bonne, Hawaii, * and 
Jonathan Cole, Hawaii, joncole at **
  * Ulrich Bonne is a semi-retired PhD Chemical Physicist in Kailua-Kona, Hawaii
** Jonathan Cole is a self-employed MBA in Honokaa, Hawaii

7 October 2012

SUMMARY -- Some historical trends are clear, such as the trend from a few large central systems to many small, “distributed” or individual ones, as demonstrated by transitions from public to individual transportation and from big central computers to lap tops. 
We believe that a similar trend is gaining traction towards distributed electricity generation. This is fueled not only by NIMBY opposition to new utility-sized plants; but now also by simple economics[1]. Distributed solar PV (photovoltaic) generation also reduces fossil fuel imports, air pollution, utility transmission losses and consumer bills. It simultaneously increases good land use. An added small energy storage yields uninterruptible power. Distributed solar generation also increases energy security and independence - as we have detailed below.
We found the 30-year levelized 3-kW home PV electricity cost in Hawaii to be 0.21 $/kWh before subsidies (or 0.23 $/kWh with cost of a loan), vs. 0.46 / 0.23 $/kWh for a central 30-MW PV- / oil-utility, or ~0.15 vs. 0.36 / 0.23 $/kWh after present PV tax credits.
            Despite well-received federal and state subsidies via renewable energy tax credits, key barriers to faster implementation of solar PV residential roof systems remain, such as:
1.      The still significant installed PV system price tag (especially if battery storage is added),
2.      The concern that lost utility profits will have to be made up by those ratepayers without solar installations, despite the utility benefit of delayed new plant capitalization, selling free excess PV capacity and income from the MMC (Minimum Monthly Charge) and
3.      The uncertainty or unwillingness by utilities to adapt by adding storage to their portfolio to compensate for the intermittent wind and solar electricity additions to their grid.
Countries in Europe have been more aggressive than the US and most US states in promoting the adoption of PV systems, as evident for example by their published Feed-in Tariff (FIT) terms[2], and ~2.5x lower PV installation costs in Germany than in the US[13]. Europe has shown that good, long-term, decreasing incentives may lead to fast deployment of PVs.  Despite the gloating of those opposed to any energy subsidies, after recent downward adjustment of those incentives[2], few disagree with the notion that PV demand
  • Has increased PV sales and also reduced PV manufacturing & installation cost.
  • Created competition and with it, increased PV panel efficiency
  • Together with wind installations have lowered European market power prices[14]
COMMENTS -- The comments below
A.  List how we recommend the DOE, DBEDT & NREL to get more involved,
B.  Illustrate the benefits of more distributed solar PVs and
C.  Demonstrate how greater support for distributed home PVs with storage would be more environmentally benign (save land area and emissions), and be more economical than support for adding utility-scale PVs, storage and transmission lines.

A. We recommend that DOE and DBEDT (Hawaii Department of Business, Economic Development and Tourism) be more forcefully involved with:
·        Understanding residential PV generation data & results, promotion and financial support
·        Validating economic and environmental advantages of home PV systems with battery storage over utility-scale systems
·        Using PVs for home Electric Vehicle (EV)  and Plug-in Hybrid EV (PHEV) charging
·        Supporting EV and PHEV battery development and usage
·        Developing policies to encourage deployment of the above, including:
-- Test & publicize efficiency & cost information on available and matching hardware
-- Structure support (e.g. tax credits) on a multi-year time scale, even showing how that support will decline as PV costs are projected to decline, and thereby avoiding past “boom and bust cycles”
-- Reduce the support that mature Big Oil still receives at the tune of some 4 B$/year, to instead support renewable residential PV systems
-- Smart grid implementations and demonstrations

B.  The benefits from the above more forceful support of home PV+battery vs. utility PV system adoption would be evident in:
·        Reduced renewable energy cost & land-for-energy use
·        Reduced air pollution from fossil fuel combustion
·        Reduced need for biomass-to-fuel processing, & its potential for increased food costs
·        Greater security for energy in homes & vehicles, and for food and water
·        Increased US local economic activity due to reduction of fossil fuel imports[3]

C.  To detail how greater support for distributed home PVs with storage would be more economical than support for utility-scale PVs, storage and transmission lines, we listed 

     and added up the main CAPEX and OPEX items for such systems in Table 1, after normalizing all items for three 3-kW(peak) home-PV (consuming 242 kWh/month), a 30-MW(peak) utility-PV and -oil installations (last 2 columns) to 1 kW(peak).  For purposes of this comparison, as shown in Table 1, bottom row A, home PV systems, whether with or without battery, generator and/or grid back-up, can generate a lower, levelized, unsubsidized, life-cycle cost of 0.20 to 0.24 $/kWh, than utility-sized PV systems, despite their size (lower PV installation costs), but because of tougher voltage and frequency stability requirements; and transmission & distribution costs and losses. With higher CAPEX and OPEX costs, PV-utilities end up with a higher price of electricity of 0.45 $/kWh (10% profit included); the oil-utility with 0.23 $/kWh was within the same range as the home-PV cost.
The Row B $/kWh costs include applicable subsidies, and shifted to a new set of values of 0.13 to 0.16 versus 0.36 / 0.23 $/kWh for the PV- and oil-utilities.
            The underlying assumptions and choice of listed costs are detailed in the Appendix.  But note that just like utilities have average utilization percentages of less than 50% of the installed US generation ability, so might home PV systems be oversized by up to 2x, to have enough generation “reserve” and to minimize the use of back-up energy from the grid or on-site generators. This extra reserve means that while the home-generated $/kWh still remain lower than the PV-utility $/kWh, the absolute $/kWh values for both home and utility-generated electricity are higher in Row C (based on a utilization of 70% for PVs and 43% for oil), resulting in the values of 0.19 to 0.23 versus 0.50 / 0.27 $/kWh.
We did not factor in the PTC (Production Tax Credit) for renewable energy by utilities. As Table 1 shows, the present credit of 2.2 cents/kWh[7] would not alter our conclusions.
To compensate for the uncertainty in the price and life of batteries, one could triple the battery cost for the middle columns from $1000 to $3000, to allow replacement every ten years. This would increase the home PV + battery total cost and the levelized $/kWh cost to 64% of the PV utility-based rate, but would not alter the conclusion that economics favor home PV systems. A similar trend was already independently reported and highlighted in 2011 by comparing home PV with utility-scale concentrating solar panels[1].
The calculations of $/kWh rates for a 2 $/gal oil-fired utility served as a further sanity check of our economic model, with its own capacity factor of 90% and utilization of 43% and found its rate to be 0.27 $/kWh (Row C), i.e. only a bit higher that the favored “Home PV+Battery On-Grid” system. However, that oil-utility rate would drop to 0.16 $/kWh if fired with 4 $/millionBtu (=0.44 $/GGE) natural gas, to the rate level close to that of the first two home PV systems in Row C.

     CONCLUSIONS -- The simple cost calculations and estimates presented in Table 1 show that the need for building and maintaining transmission lines (and the assumed 10% transmission loss) tilt the economics to significantly favor off- or on-grid home or distributed PV systems over large utility-scale PV "farms" or even oil-fired utilities, without or with subsidies.
The resulting PV-home-30-year-levelized rates ($/kWh) were estimated to be ~ 36% to 45 % of those of a PV-utility rate of 0.50 $/kWh, after including subsidies, new transmission lines, realistic capacity factors (16%) and utilization percentages (70%).  
PV home rates are even lower than $/kWh rates of 2 $/gal oil-fired utility generation of 0.27 $/kWh. This rate becomes comparable to home PV rates if the battery cost is 3x higher than the assumed $1000 for the reference 1 kW(peak) PV with 5 kWh of storage.  
Furthermore, the home PV + battery systems provide home and PHEV or EV transportation energy that is not subject to utility power outages nor to fuel / electricity cost escalations.
Regarding EV and PHEV charging, we conclude that the home PV system electricity costs, see bottom line of Table 1, are equivalent to retail gasoline prices of 5.96, 5.70, 7.25 $/gal (and 16.10 for PV-utility). But thanks to the about 4-fold higher “fuel-to-wheel” efficiency of EVs, these prices would be equivalent to enabling EVs and PHEVs to achieve over 3x lower $/mile fuel costs than conventional gasoline-powered vehicles.
Judging from prices of electricity and gasoline in many other US states and countries[8,9] being above 0.20 $/kWh and above 4 $/US gal, the prime conclusion of our comments about furthering distributed over central electricity generation holds true well beyond Hawaii or US borders. Distributed solar generation has profound economic, environmental benefits. It also dramatically increases energy, water and food security, while leaving agricultural lands for food production instead of PV-farms or bio-fuels. We would indeed have enough appropriate roof space for 100% of Hawaii County’s electricity needs, including energy for 100% conversion to EVs[11].
To summarize, we recommend that DOE, DBEDT and NREL dramatically increase its support for the development of distributed PV systems by focusing on those businesses who demonstrate best practice integrations, sizing and lowest installed cost*** of PV systems, which combine PV, storage and EV charging means. Likewise, they should watch for legislation that might hinder effective or rapid growth of distributed PV generation, as reported from Australia[12].  *** The installed cost of PV systems is 2.5x less in Germany than in the US, despite similar PV panel costs[12,13].
Our recommendations also include thoughts about the role of utilities. They could profit from distributed solar PV in a number of ways, e.g. by using their access to low-cost capital to become low-cost installers of home PV systems. Despite utility costs for centrally generated power being higher than for distributed PV and despite kWh billing reductions due to new home PV systems, we see revenue opportunities for utilities such as:
·        Reduce $/kWh rates as indicated below, to stimulate demand for more electricity business. New on-grid PV homes increase revenue via the MMC and via excess kWh sales. The “loss” of kWh sales due to conversion of one old home to PV generation can be balanced by the excess PV energy from it and about half of a new PV home installation, from both of which the utility receives MMC (Monthly Minimum Charge) revenue and for which the utility can sell the free excess PV energy.
·        Income from the MMC (Monthly Minimum Charge) – $20/month now in Hawaii County, which would allow an overall utility rate reduction by 3 and 11 cents/kWh for oil- and PV-utilities, respectively, for each new PV-home with a NEM contract added to the utility customers, 
·        Free home-PV excess PV energy, which maintains some kWh sales without fuel purchases. The sale of these excess kWh are equivalent to rate drops of 2 and 12 cents/kWh, for oil- and PV-utilities, respectively, for the assumed home PV utilization of 70% or 1.43x  PV system oversize.  Note that for a utility to maintain kWh sales as PV penetration increases, it is enough that the utility acquire 1.3 new PV-home customers for each old home “loss” to on-grid PV, because each “loss” is worth the excess energy from 1/(1.43-1) = 2.3 PV homes, including the one “lost”.
·        Revenue balance -- Even for an oil-utility, the above benefits, MMC, free PV energy and fuel savings compensate 8 + 43 + 25 = 76% of the kWh sales loss when one old home is converted to on-grid PV. By adding just a fraction (24/51 = 47%) of a new PV home to the grid, the utility will have recovered 100% of the “lost” revenue, saved 100+30+30*0.47 = 144% of the fossil fuel (it only takes 0.86% of its output to serve as back-up for these PV systems), and still distributes 30+30*0.47 = 44% of the original kWh-energy, with its transmission losses, to mostly non-PV rate payers..
·        The reduction of transmission losses per total community generated kWh from central & distributed sources is especially well achievable if PV homes are equipped with battery back-up, which further reduces and dampens transmission peaks and its losses,  besides the uninterrupted power valued by electricity consumers.
·        Decreased costs and $/kWh rates of utility-installed PV systems, because of standardization benefits, and reduced regulatory and land costs.

      The above analysis did not consider the utility dynamics of meeting the load demand minute-by-minute & 24/7, especially when increasing the contribution of distributed PV generation.  However, many regions, including Germany, found that the wind and PV day-time energy additions helped to flatten the daily load demand curve[14], reduce the operating time of costly peaking units and thus lowered the overall European $/kWh rate.

     APPENDIX – For Table 1, we assumed a conservative PV capacity factor of 16%. The ability of a PV system to deliver kWh to the home was assumed to be 1.34x greater than the average needed amount, i.e. the PV system utilization was assumed to be 70% for home and utility PV systems (free fuel !) and US-average of 43% for the fossil fuel utility. We ignored the cost of capital (which would further favor home PV systems because of its lower CAPEX), ignored inflation and fuel escalation rates, and assumed installation & miscellaneous costs to equal 100% of the equipment cost.  Exception: The home (but not the utility) PV panel cost includes installation, inverter and installer profit.

One easy-to-install PV system which may appeal to many home owners is shown in Fig.1, and is represented in Table 1 by the 3rd column from the right: Adapted from ref.[10], it features PV panels, batteries, charge controller, inverters and a disconnect switch, as needed for each parallel PV panel, so that the PV system output can be plugged into either one of many existing home (grid) outlets, like an appliance, or into a separate, uninterruptible power cord outlet or circuit, which does not get disconnected during grid outages. The shown battery back-up from the grid via a rectifier is safe, thanks to its isolation transformer.  Such a PV system, after UL-type approvals, might not even need utility or building permits as in Germany[12].


[1]     John Farrell, "Home solar PV cheaper than concentrating solar power," (blog)  February 24, 2011
[2]     Kate Garrat, ”Solar PV needs more PR power in light of subsidy cuts,” The Energy Collective, Blog, 20 Sept 2012
 [3]    Thomas Loudat, PhD (Consultant, Oahu. HI), “Analysis of the economic and fiscal impacts of the Hawaii solar energy credit for residential and commercial photovoltaic systems,” Report to Department for Business, Economic Development & Tourism (DBEDT), Hawaii, (2012), in preparation, based the “2007 DBEDT Input Output Model.” Parts of the report and the underlying model[3a] are available on DBEDT website       [3a] Binsheng Li, PhD, (Research and Economic Analysis Division, DBEDT, Hawaii), “The Hawaii State input-output study: 2007 Benchmark Report,” State of Hawaii, July 2011,
[4]     Danny King, "Plug-in vehicle battery costs of $250 per kWh coming with "dramatic" price fall," Jul 13th 2012,
[5]     Engine generators available at CostCo and others for 0.1 $/W
[6]     Rob Shikina, "Stubborn fire destroys 15-MW battery building at Kahuku wind farm," 2 Aug.'12 (Blog)
[7]     Wikipedia, “Renewable Energy/Production Tax Credit (PTC),” Energy Policy Act of 1992, Unless extended, the PTC of 2.2 cents/kWh for utilities will expire by end of 2012 
[8]     Wikipedia, “Global electricity prices by country,”, 2011 all in US cents/kWh; US 5-36, Denmark 40.38, Germany 27.81, Netherlands 28.89, Spain 22.73, UK 17.85.
[9]     Wikipedia, “Gasoline (and diesel) usage and pricing,” in $/US-gal: US ~4, Europe ~9; 2012
[10]     Jonathan Cole (Honokaa, Hawaii), "Accelerating the Solar Transition," NASA Tech Briefs, 2012 Design Contest, 23 June 2011,
[11]     U. Bonne, "Can Hawaii County Really Be Energy Self-Sufficient? (yes, with PV only!)," 6 Nov.’09,
[12]     Giles Parkinson, "How big utilities propose to kill solar PV," 9 July 2012,
[13]     Barry Cinnamon (former chief executive of Westinghouse Solar), "Cut the price of solar In half by cutting red tape," 5 July 2012,   
[14]     Craig Morris, "German wind and PV lower European market power prices," 24 July 2012,

PEIS = Programmatic Environmental Impact Statement (for Hawaii’s renewable energy goals)
The deadline for submitting written testimony is Oct 3 or 9, 2012
To get involved:
To submit comments

Sunday, August 5, 2012

Our Solar Future?

Future Planet – The Future of Solar Technology

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David Tow
David TowAUSTRALIA 5 August 2012. The Director of the Future Planet Research Centre- David Hunter Tow predicts that recent advances in solar technology may be sufficient to shift the balance from fossil to renewable energy just in time to save humanity from a likely heat death.

Solar technology is about to take off and may finally be on the threshold of displacing a large chunk of fossil fuel dependancy.

This is very good news indeed- for humans, life on Earth and possibly the Universe at large if we are the only super intelligent life form that calls it home.

Just as it seemed that the mega fossil fuel producers of coal, natural gas and oil would drive Planet Earth over the carbon cliff, major improvements in the efficiency of solar power, in tandem with advances in the sustainability of homes, workplaces and cities, has at last opened a small window of opportunity to reverse the slide to oblivion.

The solar energy absorbed by the earth’s oceans, atmosphere and land in less than two hours is more than the total energy the world uses in a year, and is twice as much as will ever be extracted from its fossil resources. The Sun therefore not only rises every day, but every day provides the means for possible salvation.

And just in time, as the planet teeters on the brink of ecosystem collapse.

A massive surge in research and innovation has pushed solar energy to the point where crossover from fossil to renewable energy is feasible, at least for most domestic, transport and light industrial applications, within the next few years.

Panic about the world’s prognosis hasn’t quite set in yet but it’s getting close, with geo-engineering trials already beginning. These involve for example the spraying of chemicals into the atmosphere to reflect sunlight to cool the earth. But the risks are high, including the possibility of reducing global rainfall and causing further damage to the ozone layer, thus threatening food supplies to billions of people and in addition allowing high polluting industries to continue to free ride, causing further irrevocable damage.

A State of the Future Report just released, with contributions by 2700 experts backed by UNESCO and the World Bank, presents another grim vision of the shortages and violence that will certainly eventuate if a solution is not found; as does the latest projections of extreme weather events by the UN International Panel for Climate Change.

With half the world facing poverty, pandemics, unemployment and violence due to scarce water, food and energy supplies, rapid climate change will be the biggest crisis the world has ever faced. But on the positive side it might also offer the incentive for humanity to become more ethically responsible in its future management of the planet, investing in the next generation of greener technologies, with Governments cooperating to achieve permanent economic sustainability, democratisation and eventually peace.

But in the meantime the situation is becoming dire and according to projections a tipping point is fast approaching. Carbon levels have reached 400 ppm in the Arctic, the same as 3 million years ago during the Pliocene era, so it’s not just a matter of short term natural variability. CO2 emissions have increased in 2011 by 3% above 2010 levels, but emissions need to decline by 3% per year to have any chance of stabilising global warming, so that by 2050 they can be at 50% of present levels.

This will be an extremely difficult goal to reach. By 2015 India and China will both have outstripped the US in energy consumption by a large margin and although making progress on the renewables front are still totally dependent on fossil fuels.

But there’s no choice about making the switch if humans are to survive. The US has just experienced one of the most extreme droughts and heat waves in its history. This is leading to massive grain and fresh water shortages globally, while at the same time putting major strains on existing electricity grid infrastructure and fuel dependency- a pattern becoming more common across the world, particularly in the developing counties of Africa and Asia.

Recently the combined strain of an expanding consumer population and a bad monsoon season, plus the high cost of imported fuel and a dysfunctional grid system, caused a rolling blackout affecting 600 million people in India – over half its population. Only the use of expensive diesel generators kept essential services such as hospitals, schools, banks and communication centres operational.

Current breakthroughs in renewable energy, particularly solar, are therefore essential. Right now with concerted action, solar plants could be built to more than meet projected electricity demand in the future, but it won’t happen quickly, because of deeply entrenched fossil fuel dependencies.

But on the bright side a number of industrial baseload energy projects are already under development including-

Desertec –part of the Great African Grid- a proof of concept project based in Morocco, aiming to supply 15% of Europe’s energy from the solar power of the Saharan desert, initially to Germany, but longer term with 56 partners from 15 countries.

Medgrid- another North African project linking solar and wind farms, with 20GW of generating capacity of which 5GW would be exported to Europe.

These and other renewable energy projects would in turn become components of a future European SuperGrid, channelling renewable energy across North Africa, the Middle East and Europe; serving as the backbone of a larger European SuperSmart Grid

A more futuristic concept is being planned by the Japanese, aiming to create the Lunar Ring project on the moon, maintained by robots, using superconducting cables to channel power from reflected sunlight to transmission centres and a receiving station near the earth’s equator for distribution to cities and towns.

At the same time, countries such as China and Germany are leading the charge in solar technology manufacturing as well as other renewables such as wind. China leads the market in green economy products such as solar cells with a huge push to reduce carbon intensity- the ratio of CO2 levels to GDP.

Germany already generates 4% of its energy from solar power. On a sunny day this can increase to over 35%, including energy from a million solar panels on houses, buildings and the sides of highways- more solar panels than rest of world combined.

Even in Saudi Arabia, the largest exporter of crude oil, the tide is turning. It produces 8.3 million barrels of crude oil daily- half consumed by the domestic market and its industries. Domestic demand will double by 2028 which would compromise lucrative export capacity. The alternative is to substitute gas for utilities. But with gas currently subsidised to 15 cents a litre it is battling to balance a high standard of living for its population and long term energy security.

It has therefore Announced a $109 billion plan to create a solar industry based on thermal concentrated solar power-CSP, to generate a third of the nation’s electricity by 2032, focussing the sun with mirrors to drive turbines and storing the energy in molten salt. With this technology the Saudis could export solar energy for next twenty centuries.

Saudi Arabia also has lots of sand rich in silicon, needed to make high quality polysilicon solar cells and has already announced partnerships with Germany and South Korea to produce up to 10,000 tonnes of extra pure polysilicon for solar cell production per year.

Despite the doomsayers, transition to a green energy regime would not reduce overall energy sector employment. The global renewables sector currently employs 5 million workers. This is estimated to increase to 30 million within two decades.

But as well as breakthroughs in technology, a major driver for adoption of renewables is the shift towards sustainable architectures for urban living. The recent advances in solar technologies referred to below, are ideally placed to support this evolution.

The transition within cities will take the form of small self-sufficient interconnected neighbourhoods, within walking or cycling distance of essential service centres. These will provide the full range of communication, education, work, health, leisure and social resources. Local transport systems will utilise advanced battery or hydrogen cell electric power technology using sunlight to split water, which will continue to improve energy density outputs.

Within ten years the impact of global warming will dominate city planning. Buildings will be designed to conserve energy, with surfaces utilising flexible thin film and organic solar panels. In addition, high growth public gardens, green belts and mini-parks will generate cooling air-flows and most surfaces will be utilised to collect runoff water to support sustainable horticulture. Efficiency and recycling savings of the order of 30% on today’s levels will be available from the application of smart adaptive technologies in power grids, communication, distribution and transport networks, manufacturing plants and consumer households. Garbage will be totally recycled, with organic waste generating significant levels of methane energy for local heating and power grid usage. Excess capacity will be fed to the major power grids, providing a constant re-balancing of energy supply across the world.

The new solar technologies are now positioned to mesh with this revolution and include advances in the following areas -

Photovoltaics – Solar photovoltaic thermal systems that can generate both heat and electricity- using amorphous silicon cells, both cheaper and with 10% greater electric output than existing crystal silicon cells. In addition low cost, high efficiency solar cells can now be tailored from any common semiconductor material such as metal oxides and sulphides. Such cells also have the potential to convert 28% of sunlight into electricity using a new technique of photon recycling.

Solar cell advances- with active layers made from carbon nano-materials having the same advantages as polymer based cells. They are flexible, tuneable and photo-stable. Advances in organic solar cells that can split particles in the polymer layer have also been achieved. These are not as efficient as inorganic solar cells but much more cost effective.

Solar Thermal Power- a first generation technology, but now with the ability to concentrate solar power using parabolic trough plates unrestricted by scarce material availability, with rare earths and silvered mirrors replaced by common commodities such as stainless steel, aluminium and glass.

.Solar Film Surface Coatings- solar power generating surface coatings using nanotechnology- allowing windows and glazed surfaces to be used as luminescent solar concentrators, with thin films absorbing sunlight and directing it to narrow solar cells at the perimeter of windows. Such surface coatings can also be used on the glazed facades of office blocks and houses. Film coatings can even be wrapped over vehicles and buildings to gain maximum sun exposure. This is a less expensive and toxic method than using non-film materials. Polymer plastic cling film solar cells that use flexible layers deposited over large areas can also be applied to produce efficient solar structures.

Printing and paint-on solar panels- ultra cheap solar energy panels for domestic and industrial using can be created using high volume printing methods, producing nanoscale films of solar cells 1000 time thinner than width of human hair. Also paint-on solar cells, using quantum dot nanoparticles of titanium dioxide painted on the outside of homes or buildings can be used to power appliances and equipment inside.

Artificial Photosynthesis- this technology mimics the natural process in plants and bacteria, converting sunlight into energy by splitting water molecules into Hydrogen and Oxygen creating free protons and electrons. Plants achieve 95% efficiency compared to 10-15% in human photovoltaic cells. Quantum effects have been discovered in first stage of plant photosynthesis, allowing different pigment molecules responsible for absorbing energy carried by light to be excited by a single photon simultaneously.

Optimised photosynthesis can be achieved by learning the deep secrets from plants and marine algae, which have natural antenna- complexes composed of chlorophyll to route the flow of energy using principles of quantum mechanics.

The above advances in solar power generation portend economies of scale, efficiency and cost that will soon begin to challenge the economics of fossil fuels, supporting commercial application, quite apart from the small issue of saving humanity from a Venusian future.

The sun has always been the dominant driver of new life for all civilisations- ancient and modern.

Now it is being asked to apply its awesome power to allow 21st century life to survive.

The question is – can the sun rise fast enough to save its planetary offspring?