A start-up company, Sunrgi, with a photovoltaics design based around focusing lenses and heat radiators claims that within 12 to 15 months they can get radically cheaper photovoltaics into mass production.
A new patents pending solar energy system will soon make it possible to produce electricity at a wholesale cost of 5 cents per kWh (kilowatt hour). This price is competitive with the wholesale cost of producing electricity using fossil fuels and a fraction of the current cost of solar energy.
XCPV (Xtreme Concentrated Photovoltaics), a system that concentrates the equivalent of more than 1,600 times the sun’s energy onto the world’s most efficient solar cells, was announced today by Sunrgi, a solar energy system designer and developer, at the National Energy Marketers Association’s 11th Annual Global Energy Forum in Washington, DC. The technology will enable power companies, businesses, and residents to produce electricity from solar energy at a lower cost than ever before.
“Solar Power at 5 cents per kWh would be a world-changing breakthrough,” said Craig Goodman, president, National Energy Marketers Association. “It would make solar generation of electricity as affordable as generation from coal, natural gas or other non-renewable sources, without requiring a subsidy.”
“In a little more than a year we were able to develop and successfully test XCPV,” said Robert S. (Bob) Block, co-founder and Sunrgi principal. “We expect the Sunrgi system to become available for both on- and off-grid power applications, worldwide, in twelve to fifteen months.”
What differentiates Sunrgi’s XCPV system from any other solar energy system includes: a proprietary, integrated low profile technology for concentrating sunlight; a proprietary technology and methodology for cooling solar cells; a low cost, modular system optimized for mass-production; less land area or “roof top” requirements than typical solar energy systems; a technology roadmap for continuous improvement; low-cost field installation; and, a custom-designed system for easy operation and maintenance.
Their device concentrates the sunlight by a factor of 1600. This allows them to use far less photovoltaic material. But it also requires excellent heat removal from the spots where the light gets concentrated. Since they use such small amounts of photovoltaics they can use highly efficient photovoltaics. So they plan to use Spectrolab (part of Boeing) PV material that is 37.5% efficient. They also track the sun during the day and so get less drop-off in power output in morning and afternoon.
Can they pull this off? Your guess is as good as mine.
Government policies spurred a rapidly rising demand for photovoltaics and these policies caused a rise in market prices. But an article in Technology Review reports some photovoltaics industry analysts are predicting a large drop in PV costs owing to rapidly growing capacity for making silicon crystals. The end of polysilicon shortages could cause PV costs to drop in half.
"It takes about two or three years to add capacity," says Travis Bradford, an industry analyst for the Prometheus Institute. The shortage has been severe enough to drive up silicon prices to more than 10 times normal levels, to $450 a kilogram, adds Ted Sullivan, an analyst at Lux Research.
The added silicon production capacity is now starting to begin operations. While only 15,000 tons of silicon were available for use in solar cells in 2005, by 2010, this number could grow to 123,000 tons, Sullivan says. And that will allow existing and planned production of solar panels to ramp up, increasing supply. "What that means, practically, is that [solar] module prices are going to come down pretty dramatically in the next two or three years," Bradford says.
Last week I linked to a PV stock analyst claiming a big drop in polysilicon costs is coming real soon now. But I'm still left wondering: How far above market prices is the manufacturing cost of polysilicon?
The rise in PV prices in the last several years might finally reverse itself. We can hope so. We need price relief from rising oil and natural gas prices. That price relief can only come in the form of cheaper substitutes.
Update: Japanese PV maker Sharp claims a new thin film PV plant will create PV cells for half the current costs.
In 2007, Sharp started operations at its Toyama plant in Japan for the manufacture of silicon for solar cells and more recently, in February 2008, it announced a collaboration with a production equipment company to develop equipment for manufacturing thin-film solar cells, giving the company a foothold in everything from raw materials to devices across a range of technologies, including polycrystalline and thin-film. In 2005, Sharp began mass production of tandem thin-film solar cells, for instance.
Sharp adds that the end of the 2009 financial year (March 2010) will see the start of operations at its new thin-film solar cell plant in Sakai City, Osaka prefecture in Japan, which will have an annual capacity of about 1 GW, the cost of generating solar power will be about half current levels in 2010. This, says Sharp, will be equivalent to around ¥23/kWh (US¢22/kWh), which is close to the current cost of domestic electricity.
The solar PV market has gotten so big with so many players and technological approaches that substantial price declines seem likely just due to the number of competing teams.
Cheap solar photovoltaics are not just around the corner.
NEW ORLEANS, April 7, 2008 — Despite oil prices that hover around $100 a barrel, it may take at least 10 or more years of intensive research and development to reduce the cost of solar energy to levels competitive with petroleum, according to an authority on the topic.
“Solar can potentially provide all the electricity and fuel we need to power the planet,” Harry Gray, Ph.D., scheduled to speak here today at the 235th national meeting of the American Chemical Society (ACS). His presentation, “Powering the Planet with Solar Energy,” is part of a special symposium arranged by Bruce Bursten, Ph.D., president of the ACS, the world’s largest scientific society celebrating the 10th anniversary of the Beckman Scholars Program.
Gray sees a big benefit from using sunlight to split water for hydrogen as a fuel.
“The Holy Grail of solar research is to use sunlight efficiently and directly to “split” water into its elemental constituents – hydrogen and oxygen – and then use the hydrogen as a clean fuel,” Gray said.
Gray is the Arnold O. Beckman Professor of Chemistry and Founding Director of the Beckman Institute at the California Institute of Technology. He is the principal investigator in an NSF funded Phase I Chemical Bonding Center (CBC) – a Caltech/MIT collaboration – and a principal investigator at the Caltech Center for Sustainable Energy Research (CCSER).
Gray sees solar as costing about 35 to 50 cents per kwh and competitive solar at least 10 years away.
The single biggest challenge, Gray said, is reducing costs so that a large-scale shift away from coal, natural gas and other non-renewable sources of electricity makes economic sense. Gray estimated the average cost of photovoltaic energy at 35 to 50 cents per kilowatt-hour. By comparison, other sources are considerably less expensive, with coal and natural gas hovering around 5-6 cents per kilowatt-hour.
Because of its other advantages – being clean and renewable, for instance – solar energy need not match the cost of conventional energy sources, Gray indicated. The breakthrough for solar energy probably will come when scientists reduce the costs of photovoltaic energy to about 10 cents per kilowatt-hour, he added. “Once it reaches that level, large numbers of consumers will start to buy in, driving the per-kilowatt price down even further. I believe we are at least ten years away from photovoltaics being competitive with more traditional forms of energy.”
Solar energy won't become cost competitive everywhere at the same time. In areas with higher electricity costs and greater amounts of sunlight (e.g. southern California) solar becomes cost competitive sooner at a much higher price for the solar panels than it does in, say, British Columbia or Sweden.
Can an expert predict reliably that solar won't become cost competitive for 10 years? Or can lots of start-ups with lots of venture capital surprise the academics?
In recent years prices for solar panels haven't dropped at all. Growing demand, driven by tax credits and other government interventions, has kept prices up even as production capacity has soared. In spite of its northern geographic location and relatively low light levels government incentives have turned Germany into the biggest source of demand for photovoltaics. When government-caused demand growth flattens out will solar photovoltaics prices plummet?
A spin-off from MIT expects to achieve $1 per watt solar photovoltaic cells by 2012.
An MIT researcher has found a way to significantly improve the efficiently of an important type of silicon solar cells while keeping costs about the same. The technology is being commercialized by a startup in Lexington, MA, called 1366 Technologies, which today announced its first round of funding. Venture capitalists invested $12.4 million in the company.
1366 Technologies claims that it improves the efficiency--a measure of the electricity generated from a given amount of light--of multicrystalline silicon solar cells by 27 percent compared with conventional ones.
The company expects other improvements to combine to get it to its $1/watt goal by 2012.
They expect to achieve a 25% conversion efficiency of photonic energy into electricity.
MIT Professor, 1366 founder and CTO, Ely Sachs, noted that 1366 Technologies will be combining innovations in silicon cell architecture with manufacturing process improvements to bring multi-crystalline silicon solar cells to cost parity with coal-based electricity.
Sachs added, "The science is understood, the raw materials are abundant and the products work. All that is left to do is innovate in manufacturing and scale up volume production, and that's just what we intend to do." The company has just taken space in Lexington to build its pilot solar cell manufacturing facility.
1366 Technologies' roadmap includes a new cell architecture that uses innovative, low-cost fabrication methods to increase the efficiency of multi-crystalline solar cells. This architecture, developed at MIT, improves surface texture and metallization to enhance silicon solar cell efficiency by 25% (from 15 - 19%) while lowering costs.
1366 has some heavyweight competitors.
And what will happen if 1366’s claims pan out, and silicon-based solar cells really drop below $1 per watt within the next few years? If the costs for those cells, solar PV, drop more rapidly than expected, thin-film solar based on other materials could face more challenges than expected. However, companies that make thin-film cells like First Solar (NASDAQ: FSLR) and Nanosolar (coverage here) are working on their own process improvements, and it’s difficult to tell when breakthroughs will come.
As of this writing First Solar (FSLR) has a market capitalization of almost $18 billion. So the markets think First Solar could be the winner. So will 1366 score an upset? Photovoltaics makers can raise the capital needed if they can just come up with plausible technologies for lowering photovoltaics costs.
A pair of articles from MIT's Technology Review report on prospects of lower solar photovoltaics manufacturing costs. First, Solaria is developing cheaper ways to make cheaper silicon-crystal based photovoltaic using thinner cells and lower cost fabrication techniques.
Solaria, a startup based in Fremont, CA, intends to cut the cost of solar panels by decreasing the amount of expensive material required. It has recently started shipping its first panels to select customers. This spring the company will begin production of solar panels at a factory built to produce 25 megawatts of solar panels per year.
Current high costs for the type of silicon used in photovoltaics have significantly driven up the price of conventional solar panels. Solaria's cells generate about 90% of a conventional solar panel's power, while using half as much silicon, says Kevin Gibson, Solaria's CTO.
The eventual expected cost reduction is only 10 to 30 percent.
Gibson says Solaria's first products will be economical enough to compete with panels produced by much larger companies, and that successive product generations will cost between 10 and 30 percent less than their competitors.
We need a much larger drop in photovoltaics cost. But 30% would be very substantial.
An approach using titanium oxide nanocrystals and organic dyes has the potential for much larger price reductions.
Cheap and easy-to-make dye-sensitized solar cells are still in the early stages of commercial production. Meanwhile, their inventor, Michael Gratzel, is working on more advanced versions of them. In a paper published in the online edition of Angewandte Chemie, Gratzel, a chemistry professor at the École Polytechnique Fédérale de Lausanne in Switzerland, presents a version of dye-sensitized cells that could be more robust and even cheaper to make than current versions.
Dyes made out of organic material could be very cheap.
New dyes are also being investigated. In commercial cells, the dyes are made of the precious metal ruthenium. But researchers have recently started to consider organic molecules as an alternative. "Organic dyes will become important because they can be cheaply made," Gratzel says. In the long run, they might also be more abundant than ruthenium.
Costs of new nuclear and coal power plant construction have skyrocketed. So the price point that solar has to get down to in order to compete has risen. Competitive photovoltaics probably require at least a two thirds price cut to below $1/Watt capacity. When will that happen? Your guess is as good as mine.
A new solar thermal electric power installation in Boulder City Nevada uses arrays of mirrors to concentrate sun light to drive electric power generation. The cost of electricity for this plant is estimated at 15-20 cents per kilowatt-hour (kwh).
Many states, including California, are imposing mandates for renewable energy. All of that is reviving interest in solar thermal plants.
The power they produce is still relatively expensive. Industry experts say the plant here produces power at a cost per kilowatt- hour of 15 to 20 cents. With a little more experience and some economies of scale, that could fall to about 10 cents, according to a recent report by Emerging Energy Research, a consulting firm in Cambridge, Mass. Newly built coal-fired plants are expected to produce power at about 7 cents per kilowatt-hour or more if carbon is taxed.
That is at least double what cheaper sources of electricity cost in the United States. Can the costs really go down substantially with a bigger market?
While solar thermal still costs more than wind power predictable daylight hours and the ability to store the heat allows solar thermal to provide a more reliable power source.
According to the U.S. Department of Energy, wind power costs about 8 cents per kilowatt, while solar thermal power costs 13 to 17 cents. But power from wind farms fluctuates with every gust and lull; solar thermal plants, on the other hand, capture solar energy as heat, which is much easier to store than electricity. Utilities can dispatch this stored solar energy when they need it--whether or not the sun happens to be shining.
Solar thermal doesn't have to be able to provide electric power 24 hours per day to be useful. If its cost could drop in half then solar thermal would greatly reduce the use of coal and natural gas and allow limited fossil fuels to last longer and pollute less..
Acciona's plant, which began operation last year, produces 64 megawatts of electricity for the utility company Nevada Power, enough to light up 14,000 homes. The company's Spanish competitor Abengoa just announced a plan to build a 280-megawatt solar thermal plant outside Phoenix, which would be the largest such project in the world.
All you need is a lot of sun, a lot of space and a lot of mirrors — and NS1 has all of the above. 182,000 parabolic mirrors are spread over 400 acres of flat desert, creating a glistening sea of glass visible from miles away.
That's 35 homes worth of electric power per acre of land. Mind you, this is an area of the United States that gets above average amounts of sunlight. But this result suggests that use of solar thermal to power all homes would not use an inordinate amount of land - at least not in countries with lower population densities.
Solar thermal looks cheaper than solar photovoltaics and the heat from solar thermal can be stored to stretch into evening hours. But solar photovoltaics might have better prospects for lower cost reductions and it lends itself more easily to decentralized use and smaller installations on homes and other buildings.
A solar concentrator steam system has achieved a new efficiency record for its type.
ALBUQUERQUE, N.M. —On a perfect New Mexico winter day — with the sky almost 10 percent brighter than usual — Sandia National Laboratories and Stirling Energy Systems (SES) set a new solar-to-grid system conversion efficiency record by achieving a 31.25 percent net efficiency rate. The old 1984 record of 29.4 percent was toppled Jan. 31 on SES’s “Serial #3” solar dish Stirling system at Sandia’s National Solar Thermal Test Facility.
The conversion efficiency is calculated by measuring the net energy delivered to the grid and dividing it by the solar energy hitting the dish mirrors. Auxiliary loads, such as water pumps, computers and tracking motors, are accounted for in the net power measurement.
“Gaining two whole points of conversion efficiency in this type of system is phenomenal,” says Bruce Osborn, SES president and CEO. “This is a significant advancement that takes our dish engine systems well beyond the capacities of any other solar dish collectors and one step closer to commercializing an affordable system.”
Phenomenal? If it took them 24 years to gain 2% of efficiency and it is still more expensive than coal electric or nuclear (and that's probably the case) then I'm not so excited.
Improved optics helped to achieve this record.
Andraka says the first and probably most important advancement was improved optics. The Stirling dishes are made with a low iron glass with a silver backing that make them highly reflective —focusing as much as 94 percent of the incident sunlight to the engine package, where prior efforts reflected about 91 percent. The mirror facets, patented by Sandia and Paneltec Corp. of Lafayette, Colo., are highly accurate and have minimal imperfections in shape.
Note, however, that they also benefited from a cold day. This suggests that in sustained operation the real efficiency would be lower.
The temperature, which hovered around freezing, allowed the cold portion of the engine to operate at about 23 degrees C, and the brightness means more energy was produced while most parasitic loads and losses are constant.
Still, they've moved the state of the art closer to commercial feasibility. But will nanomaterial photovoltaics blow right past stirling engines for lower cost solar power? Or can the solar concentrator approach fall substantially in cost too?
Nanoptek, a startup based in Maynard, MA, has developed a new way to make hydrogen from water using solar energy. The company says that its process is cheap enough to compete with the cheapest approaches used now, which strip hydrogen from natural gas, and it has the further advantage of releasing no carbon dioxide.
Nanoptek, which has been developing the new technology in part with grants from NASA and the Department of Energy (DOE), recently completed its first venture-capital round, raising $4.7 million that it will use to install its first pilot plant. The technology uses titania, a cheap and abundant material, to capture energy from sunlight. The absorbed energy releases electrons, which split water to make hydrogen. Other researchers have used titania to split water in the past, but Nanoptek researchers found a way to modify titania to absorb more sunlight, which makes the process much cheaper and more efficient, says John Guerra, the company's founder and CEO.
Suppose this Nanoptek approach really works and eventually can be used to make hydrogen cheaply. What to do with it? Hydrogen is still difficult to transport and store. But hydrogen attached to carbon is very useful in both gas and liquid forms. The problem then becomes where to get the carbon? Ethanol seems a good candidate. It contains a partially oxidized carbon that'd be more useful if its oygen got replaced with a hydrogen. That would lead to ethane and eventually ethylene. The ethylene has many industrial chemical uses.
The hydrogen could also be used with the exhaust of an coal electric power plant to combine with the carbon in the carbon dioxide to again make reduced carbon in gaseous or liquid form. A hydrocarbon with longer carbon chains would be ideal since it would be liquid at room temperature and hence useful for powering cars and trucks. So a light-driven process for splitting water would be most useful combined with a process to reduce carbon into liquid hydrocarbon molecules.
How about incredibly cheap photovoltaics with high conversion efficiency?
Researchers at Idaho National Laboratory, along with partners at Microcontinuum Inc. (Cambridge, MA) and Patrick Pinhero of the University of Missouri, are developing a novel way to collect energy from the sun with a technology that could potentially cost pennies a yard, be imprinted on flexible materials and still draw energy after the sun has set.
The new approach, which garnered two 2007 Nano50 awards, uses a special manufacturing process to stamp tiny square spirals of conducting metal onto a sheet of plastic. Each interlocking spiral "nanoantenna" is as wide as 1/25 the diameter of a human hair.
Because of their size, the nanoantennas absorb energy in the infrared part of the spectrum, just outside the range of what is visible to the eye. The sun radiates a lot of infrared energy, some of which is soaked up by the earth and later released as radiation for hours after sunset. Nanoantennas can take in energy from both sunlight and the earth's heat, with higher efficiency than conventional solar cells.
"I think these antennas really have the potential to replace traditional solar panels," says physicist Steven Novack, who spoke about the technology in November at the National Nano Engineering Conference in Boston.
Plastic is orders of magnitude cheaper than the polysilicon crystal used in the expensive photovoltaics of today.
They think they can achieve a very high efficiency of energy conversion.
Commercial solar panels usually transform less that 20 percent of the usable energy that strikes them into electricity. Each cell is made of silicon and doped with exotic elements to boost its efficiency. "The supply of processed silicon is lagging, and they only get more expensive," Novack says. He hopes solar nanoantennas will be a more efficient and sustainable alternative.
The team estimates individual nanoantennas can absorb close to 80 percent of the available energy.
An order of magnitude drop in the cost of photovoltaics would make energy storage our biggest problem. The sun does not always shine. But when it does cheap photovoltaics would make photovoltaic electricity the cheapest source of power.
Super cheap solar electric would make more industries seasonal. For example, put the cost of electricity below 1 cent per kilowatt-hour in Arizona from the first day of spring through summer and it might make sense to do a full year's Aluminum smelting in 6 months in Arizona. Or maybe do all the smelting in 4 months.
Nitrogen fertilizer production could become seasonal as well. Use cheap electric power to fix hydrogen to nitrogen during the spring before crops get planted. Keep making fertilizer during the summer for use the next year. Other chemical feedstock synthesis could similarly be done when the power is very cheap.
Skyrocketing demand has kept up the prices for solar photovoltaics for several years running. However, the Earth Policy Institute expects rising production capacity to finally cause a big decline in photovoltaics cost in the next few years.
The average price for a PV module, excluding installation and other system costs, has dropped from almost $100 per watt in 1975 to less than $4 per watt at the end of 2006. (See data.) With expanding polysilicon supplies, average PV prices are projected to drop to $2 per watt in 2010. For thin-film PV alone, production costs are expected to reach $1 per watt in 2010, at which point solar PV will become competitive with coal-fired electricity. With concerns about rising oil prices and climate change spawning political momentum for renewable energy, solar electricity is poised to take a prominent position in the global energy economy.
Regarding competitiveness with coal: There are the not so minor details of where and when. Certainly photovoltaics become cost competitive in Arizona before Colorado and in Colorado before Alberta or England. So in the more northern climes and in cloudier areas the prices of photovoltaics will have to drop much further before becoming competitive. Also, photovoltaics will compete on June 21 in the northern hemisphere years before they compete on March 21, let alone December 21. Plus, we need really cheap electric power storage before day time photovoltaic energy will help us much during the night time. So keep in mind all the caveats and short-comings of solar power when you read rosy scenarios about solar energy.
The company which many observers think has the best chance to cause this big cost decrease is Nanosolar. CEO Martin Roscheisen says Nanosolar can get their production costs below $1 per watt.
- the world’s first printed thin-film solar cell in a commercial panel product;
- the world’s first thin-film solar cell with a low-cost back-contact capability;
- the world’s lowest-cost solar panel – which we believe will make us the first solar manufacturer capable of profitably selling solar panels at as little as $.99/Watt;
- the world’s highest-current thin-film solar panel – delivering five times the current of any other thin-film panel on the market today and thus simplifying system deployment;
- an intensely systems-optimized product with the lowest balance-of-system cost of any thin-film panel – due to innovations in design we have included.
The printed thin film process with which Nanosolar has just started commercial production looks like the ticket. They avoid the costs of the thick polysilicon crystals and supposedly can produce at fast speed using a printing technology.
The San Jose-based Nanosolar developed a proprietary ink that is based on “nanoparticles” of a material called copper indium gallium selenide (CIGR), which can be printed on metal foil, which is cheaper and 20 times more conductive than stainless steel.
Other companies that also specialise in 'thin-film solar' technology also use CIGRs, but require a vacuum chamber to disperse the particles. Nanosolar says its method of printing is cheaper and more effective. It can literally produce huge rolls of the product that are metres wide and up to kilometers long.
But Nanosolar is already sold out into 2009. If their process turns them a big profit during this time they obviously can and will ramp up. So how quickly will they ramp up? Will they run into troubles running their manufacturing process continuously?
A Japanese spherical solar cell design promises a big photovoltaic power price drop.
A company in Japan has developed a novel way of making solar cells that cuts production costs by as much as 50 percent. The photovoltaic (PV) cells are made up of arrays of thousands of tiny silicon spheres surrounded by hexagonal reflectors.
The key advantage of the system is that it reduces the total amount of silicon required, says Mikio Murozono, president of Clean Venture 21 (CV21), based in Kyoto, Japan. "We use one-fifth of the raw silicon material compared with traditional PV cells," he says.
I am optimistic about cheaper photovoltaics for two reasons. First, it is a solvable problem. Second, many more teams in academia, government, and industry are trying to solve it.
A halving of photovoltaic prices would make photovoltaics competitive in much of the US southwest. So if this company achieves its goal photovoltaics sales will take off.
CV21 started production of its cells in October; the first of its 10-kilowatt modules go on sale this month. While these modules will initially cost about the same as the traditional variety, the price is set to drop by 30 percent in 2008, as production increases in May from 1,000 cells a day to 60,000 cells a day, says Murozono. The ultimate goal is to make them 50 percent cheaper than existing cells by 2010, he says.
Some people that once we pass the peak in world oil production we are at risk of deindustrialization. I don't see it. Sure some parts of the world are going to be very hard it. Some oil emirates and less advanced countries are at risk. For fully industrialized countries I expect some deep recessions and a period of stagnant or declining living standards. But I do not think that the industrialized countries are at risk for total collapse. We have too many sharp scientists and technologists and too many ways to solve the problem of dwindling reserves of liquid hydrocarbons.
Our current high oil prices and this period of a world oil production plateau are actually fortunate for our prospects in a post-peak world. The higher prices are providing incentives for the development of substitutes. The post peak decline hasn't come on so suddenly that we lack time to adjust. People who want to feel total doom and gloom about the future should look elsewhere. Energy shortages aren't going to bring down industrial civilization.
Among the American states California has the strongest incentives for installing photovoltaics .
In its Northern California service territory, PG&E charges tiered rates for electricity, between 11.4 cents and 36.4 cents a kilowatt-hour, depending on usage. (A kilowatt-hour equals the energy needed to run a 100-watt bulb for 10 hours.) Utility spokesman John Tremayne says the average PG&E customer pays about 15 cents a kilowatt-hour, including surcharges and fees.
Solar power generated with photovoltaic panels, meanwhile, will run a homeowner about 18 to 19 cents a kilowatt-hour, assuming a cost of $24,000 to install a system that produces 4,300 kilowatt-hours of electricity, over 30 years, according to Barry Cinnamon, president and chief executive of Akeena Solar Inc., a solar-power installer based in Los Gatos, Calif.
Some customers have managed to cut their installation costs to as little as $15,000 after state rebates and a $2,000 federal tax credit, which, over a 30-year period, would produce power for about 10 to 14 cents a kilowatt-hour, according to Mr. Cinnamon, who says PG&E rates in his area are around 36 cents a kilowatt-hour, after surcharges and fees.
Half of the growth in solar power in the US until 2015 is expected to come in California. The article emphasizes state government incentives as an explanation for this. But California also has electricity costs that are, at the time of this writing about 37% above the national average. So solar doesn't have to become as cheap in California as it does in really cheap electricity states (below 8 cents per kwh) like Washington, North Dakota, Idaho, or Kentucky. Also, southern California has less clouds and more sunshine than most US states (Arizona notably excepted). So the same solar panels produce a lot more electricity in San Diego than they do in Milwaukee or Bangor or Seattle.
I think it hard to project solar installation growth out to 2015 for a reason that seems obvious from the excerpt above: Solar power's cost is not enormously above existing utility power. A reduction in solar's cost by a half or two thirds would make solar pretty competitive in Arizona and southern California. By 2015 Solar's cost could conceivably fall to a point where it becomes competitive in the the most sunny areas.
Once the choice only of idealists who put the environment before economics, production of solar panels will double both next year and in 2009, according to U.S. investment bank Jefferies Group Inc, driven by government support especially in Germany and Japan.
A high ranking engineer at General Electric says in some parts of the United States photovoltaics will become cost competitive by 2015.
"At that point you can expect pretty much unbounded growth," General Electric Co's Chief Engineer Jim Lyons told the Jefferies conference in London on Thursday, referring to price parity in sunny parts of the United States by around 2015.
"The solar industry will eventually be bigger than wind."
Solar energy will become bigger than wind for a few reasons. First off, there is more energy outside in the form of photon torpedoes (sorry, couldn't resist) than in the form of air flowing. Wind is just one side effect of heating caused by those photons showering down on the planet. Second, while photovoltaic materials are currently rather expensive they have much greater potential to become dirt cheap than wind towers do. Third, photovoltaic installations hit fewer obstacles. Your neighbors are less likely to mind photovoltaics on your roof (especially when future photovoltaic materials are made to look like roof tiles) than they are a tower sticking up out of our yard 100 feet and making noise as the wind spins the blades.
Here's an example of approaches that hold the potential to make photovoltaics very cheap.
Researchers at Harvard University have made solar cells that are a small fraction of the width of a human hair. The cells, each made from a single nanowire just 300 nanometers wide, could be useful for powering tiny sensors or robots for environmental monitoring or military applications. What's more, the basic design of the solar cells could be useful in large-scale power production, potentially lowering the cost of generating electricity from the sun.
We do not face a general energy shortage. We face a liquid fuels shortage. Solar is going to join wind and nuclear as non-fossil fuels sources of electricity that could replace most of the fossil fuels now used to generate electricity.
Given cheap, dependable, and high energy density batteries we could shift most transportation to electricity and most electric generation to non-fossil fuels energy sources. That is the path we need to follow to the post Peak Oil era.
Engineer-Poet explains we will have huge amounts of energy available once photovoltaics become cheap.
Annual energy consumption of the USA is about 98000 kWh of primary energy per capita. A square meter in the middle of Kansas receives about 1550 kWh of solar energy per year, so an American's consumption represents about 63 square meters of Kansas. 300 million Americans would need about 7300 square miles out of the 81,815 square miles of the state. Even if you reduced efficiency to 10%, you wouldn't need the entire state. We probably have enough area under roofs and roads to do the job already, no further development required.
We have PV made of silicon (27% of Earth's crust) and PV made of organics (representing carbon, possibly reclaimed from the atmosphere) on the way. Carbon nanowires are already better conductors than copper. Technology inevitably pushes to the limits of science (just compare the 14-inch Winchester disk drives of 3 decades ago to the one in the iPod). The science we have today is enough to supply an American level of comfort to billions, albeit using renewables rather than fossil fuels.
E-P thinks he knows a way to extract silicon for photovoltaics at a much lower cost. Not sure he's right about that. But I agree with him that it is a solvable problem.
Our problem is not a general energy shortage. What we are hitting is a liquid energy shortage. The development of technologies to allow electricity to substitute more for liquid fuels will allow us to move past the liquid fossil fuels era and enjoy rising living standards. But we might go through a painful transition before the batteries and other elements of our more electrified society come together.
Rooftop photovoltaic installs are still a drop in the bucket.
Photovoltaic cells, most of which are made from silicon, have exploded in use around the country over the past five years as once-prohibitive costs for home use of the technology have declined. Between 2002 and 2006, the number of new photovoltaic systems installed in U.S. homes nearly tripled to 7,446 from 2,805, according to the Interstate Renewable Energy Council in Latham, N.Y. Industry officials say that such installations are expected to top 11,000 this year.
To put this in perspective the United States has about 70 million single family detached housing units. The yearly installation rate would have to go up by a factor of over 6000 to reach 1% of the existing single family home housing units per year (more for attached townhouses, apartment buildings, and other housing structures).
Sun Run's contract--called a purchased power agreement--won't eliminate the initial cost of getting solar electricity. But it will reduce by about 60 percent the pain of shelling out anywhere from $20,000 to $35,000 for solar panels, according to the company.
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Akeena Solar's Andalay panel is supposed to cut installation time from four hours to 30 minutes. It's also meant to be more attractive and look like a skylight.
Sharp Solar, the largest solar panel maker in the world, has started to promote a pre-fab solar system to the U.S. market.
Ultimately what we need are photovoltaic shingles or tiles so that putting a new roof on a house installs photovoltaic materials. That would make most of photovoltaic installation cost just part of the existing cost of roofing installs.
Increasing demand for solar power,engineered by governments, has kept solar prices stable over the last 12 months. Prices have stayed close to $5-6/watt.
In 2005, silicon solar cell production was measured at 1.7 Gigawatts (GW) globally. That number is expected to grow to 10 GW by 2010. At the same time the electronic sector is growing at a five percent annual rate.
Another source shows solar module prices have risen about 11 percent in the last 3 years. That's a little higher than the overall rate of inflation. So we are not on a downward trend in solar photovoltaic prices. Government-engineered increase in demand (especially in Germany which accounts for half of all photovoltaic demand
Most of the decline in photovoltaics prices occurred before 1987. But this latest surge in demand for solar, especially in Germany, is driving a big increase in manufacturing capacity. Costs should drop once production capacity catches up with government-caused increases in demand. If a photovoltaics manufacturer achieves a really big breakthrough in costs we should see a much more rapid increase in manufacturing capacity and a big drop in prices. Using concentrating parabolic reflectors and a thermal storage system Palo Alto California company Ausra claims to have a workable way for solar power to supply electricity 24 hours per day. Ausra claims to have solved the storage problem without using molten salts or other expensive means of conserving heat. In fact, the company estimates that the price of its electricity will drop to roughly 8¢ per kilowatt hour if it can store heat for 16 hours. "Thermal storage is generally considered to be quite a bit cheaper than electrical storage," says Nate Blair, a senior analyst at NREL. "There isn't a lot of power generation combined with storage systems that can take advantage of that. [Concentrated solar power] has a leg up on storage in the grid or flow batteries or even ultracapacitors." The system will employ pressure and a steam accumulator to accomplish the trick. "You allow some of the steam to recondense," O'Donnell explains. "It flashes back to steam when you reduce the pressure just by opening the valve to the turbine." Such long-term steam storage, however, is unproved. "Steam storage is currently feasible at small levels, for example, one hour or so," NREL's Mehos notes. "Due to large volumes and high pressures involved with steam storage, scaling up steam storage to baseload applications is very high risk." Water boils at different temperatures at different atmospheric pressures. At high altitudes with thinner air and less atmospheric pressure water boils at lower temperatures. But put water under a sufficiently intense pressure and it will not boil into vapor. The idea is to store the water under high pressure so that it won't convert to steam and then release some of the water into a lower pressure area at night to allow the water to convert into high pressure steam and power turbines to generate electricity. I don't know whether they can make it work. But this is an interesting approach. Store the energy as hot water rather than as hydrogen or electrochemically in a battery. Can they make this approach work? The storage container has to meet cost, pressure, and longevity goals. What sort of storage material could do this? Steel? Is insulation needed? FORT COLLINS - Today, Colorado State University is taking another big step toward making Colorado a leader in sustainable energy production. Already internationally known for research in the development of clean energy solutions including alternative fuels, clean engines and intelligent power grids, Colorado State announced its innovative method for manufacturing low-cost, high-efficiency solar panels is nearing mass production - bringing hundreds of jobs to the region and potentially providing light and power for billions in the underdeveloped world. In a new 200-megawatt factory, expected to employ up to 500 people, AVA Solar Inc. will start production by the end of next year on the pioneering, patented technology developed by mechanical engineering Professor W.S. Sampath at Colorado State. Based on the average household usage, 200 megawatts will power 40,000 U.S. homes. Produced at less than $1 per watt, the panels will dramatically reduce the cost of generating solar electricity and could power homes and businesses around the globe with clean energy for roughly the same cost as traditionally generated electricity. Cheap! With installation the $2 per watt expected cost is still much lower than current photovoltaics. The cost to the consumer could be as low as $2 per watt, about half the current cost of solar panels, and competitive with cost of power from the electrical grid in many parts of the world. In addition, this solar technology need not be tied to a grid, so it can be affordably installed and operated in nearly any location. They say their manufacturing process will be highly efficient. -Simple manufacturing process - fully automated and continuous production with no batch processing yielding high throughputs or production rates; They also claim their process uses far less semiconductor material than crystalline silicon panels. -Inexpensive, efficient raw materials - because they convert solar energy into electricity more efficiently, cadmium telluride solar panels require 100 times less semiconductor material than high-cost crystalline silicon panels. The era of cheap solar photovoltaics is no longer a distant prospect. Powered by $77 million in new investment, startup Heliovolt, based in Austin, TX, will build a factory next year for mass-producing a new type of solar cell that could, in much of the United States, make solar electricity as cheap as electricity from the grid. The company will be scaling up a new manufacturing technique that could produce high-performance thin-film solar cells more reliably than other methods. Heliovolt is one of several startups developing a type of thin-film solar cell that converts light into electricity with a micrometers-thick layer of a copper-indium-gallium selenide (CIGS) semiconductor. Thin-film solar cells are attractive because they could produce electricity cheaper than conventional silicon solar cells. Read the details in the linked MIT Technology Review article. We have a problem with a looming fossil fuels shortage, especially for liquid fuel. But we do not face a general energy shortage or peak energy production problem. If necessary (or if we just get disgusted enough by conventional pollution) nuclear power could displace coal for electric power generation. Wind electric costs are going to go down and wind's role will grow. Also, one or more of an assortment of venture capital photovoltaics start-ups will bring low cost solar to the masses. With all the fine minds chasing this challenge I'll be surprised if photovoltaics aren't cost competitive for the American southwest within 5 to 7 years and for more temperate climates within 10 to 15 years. A typical solar cell generates only one electron per photon of incoming sunlight. Some exotic materials are thought to produce multiple electrons per photon, but for the first time, the same effect has been seen in silicon. Researchers at the National Renewable Energy Laboratory (NREL), in Golden, CO, showed that silicon nanocrystals can produce two or three electrons per photon of high-energy sunlight. The effect, they say, could lead to a new type of solar cell that is both cheap and more than twice as efficient as today's typical photovoltaics. This approach might achieve 40% efficiency of conversion. That's more than double what you'll find on the market today. (someone correct me if they know about commercial photovoltaic cells above 20% conversion efficiency) By generating multiple electrons from high-energy photons, solar cells made of silicon nanocrystals could theoretically convert more than 40 percent of the energy in light into electrical power, says Arthur Nozik, a senior research fellow at NREL. These researchers think silicon nanocrystals will be cheaper to make than multijunction photovoltaics that have achieved even higher efficiency. Given the multitude of approaches for achieving higher efficiency and lower costs our chances of getting cheaper photovoltaics seem high. Cheap solar will some day make noon time the cheapest time to buy electricity. But will stationary battery storage ever become cheap enough to allow solar to compete for baseload demand? Also see Boeing Spectrolab Achieves 40% Solar Cell Efficiency and Metamorphic Materials Increase Solar Photovoltaic Efficiency. Update: Another report finds silicon nanoparticles improve solar cell efficiency. CHAMPAIGN, Ill. — Placing a film of silicon nanoparticles onto a silicon solar cell can boost power, reduce heat and prolong the cell’s life, researchers now report. “Integrating a high-quality film of silicon nanoparticles 1 nanometer in size directly onto silicon solar cells improves power performance by 60 percent in the ultraviolet range of the spectrum,” said Munir Nayfeh, a physicist at the University of Illinois and corresponding author of a paper accepted for publication in Applied Physics Letters. A 10 percent improvement in the visible range of the spectrum can be achieved by using nanoparticles 2.85 nanometers in size, said Nayfeh, who also is a researcher at the university’s Beckman Institute. In conventional solar cells, ultraviolet light is either filtered out or absorbed by the silicon and converted into potentially damaging heat, not electricity. In previous work, however, Nayfeh showed that ultraviolet light could efficiently couple to correctly sized nanoparticles and produce electricity. That work was reported in the August 2004 issue of the journal Photonics Technology Letters. A consortium of research teams has achieved a new record in photovoltaic cell efficiency. 5:14 p.m., July 23, 2007--
Using a novel technology that adds multiple innovations to a very high-performance crystalline silicon solar cell platform, a consortium led by the University of Delaware has achieved a record-breaking combined solar cell efficiency of 42.8 percent from sunlight at standard terrestrial conditions. That number is a significant advance from the current record of 40.7 percent announced in December and demonstrates an important milestone on the path to the 50 percent efficiency goal set by the Defense Advanced Research Projects Agency (DARPA). In November 2005, the UD-led consortium received approximately $13 million in funding for the initial phases of the DARPA Very High Efficiency Solar Cell (VHESC) program to develop affordable portable solar cell battery chargers. Combined with the demonstrated efficiency performance of the very high efficiency solar cells' spectral splitting optics, which is more than 93 percent, these recent results put the pieces in place for a solar cell module with a net efficiency 30 percent greater than any previous module efficiency and twice the efficiency of state-of-the-art silicon solar cell modules. What I want to know: Are these materials inherently more or less expensive to manufacture for unit area than existing silicon photovoltaics? Do these materials lend themselves to greater cost reductions? Big money is going to go into creation of a manufacturing prototype. As a result of the consortium's technical performance, DARPA is initiating the next phase of the program by funding the newly formed DuPont-University of Delaware VHESC Consortium to transition the lab-scale work to an engineering and manufacturing prototype model. This three-year effort could be worth as much as $100 million, including industry cost-share. The professors leading this effort are aiming for 50% efficiency. The ground-breaking research was led by Allen Barnett, principal investigator and UD professor of electrical and computer engineering, and Christiana Honsberg, co-principal investigator and associate professor of electrical and computer engineering. The two direct the University's High Performance Solar Power Program and will continue working to achieve 50 percent efficiency, a benchmark that when reached would mean a doubling of the efficiency of terrestrial solar cells based around a silicon platform within a 50-month span. Some are skeptical over whether solar electric energy will ever amount to much after decades of failing to become cost competitive. But my view is that many breakthroughs took decades to achieve. The fact that researchers have been searching for cheaper photovoltaic materials for decades isn't an argument against the feasibility of this quest. Rather, the number of first class minds pursuing this quest strongly suggests the ultimate goal of cheap and high efficiency photovoltaics is achievable. Researchers at New Jersey Institute of Technology (NJIT) have developed an inexpensive solar cell that can be painted or printed on flexible plastic sheets. “The process is simple,” said lead researcher and author Somenath Mitra, PhD, professor and acting chair of NJIT’s Department of Chemistry and Environmental Sciences. “Someday homeowners will even be able to print sheets of these solar cells with inexpensive home-based inkjet printers. Consumers can then slap the finished product on a wall, roof or billboard to create their own power stations.” “Fullerene single wall carbon nanotube complex for polymer bulk heterojunction photovoltaic cells,” featured as the June 21, 2007 cover story of the Journal of Materials Chemistry published by the Royal Society of Chemistry, details the process. The Society, based at Oxford University, is the British equivalent of the American Chemical Society.
These solar cells are built out of carbon nanotubes and carbon fullerenes. The solar cell developed at NJIT uses a carbon nanotubes complex, which by the way, is a molecular configuration of carbon in a cylindrical shape. The name is derived from the tube’s miniscule size. Scientists estimate nanotubes to be 50,000 times smaller than a human hair. Nevertheless, just one nanotube can conduct current better than any conventional electrical wire. “Actually, nanotubes are significantly better conductors than copper,” Mitra added. Mitra and his research team took the carbon nanotubes and combined them with tiny carbon Buckyballs (known as fullerenes) to form snake-like structures. Buckyballs trap electrons, although they can’t make electrons flow. Add sunlight to excite the polymers, and the buckyballs will grab the electrons. Nanotubes, behaving like copper wires, will then be able to make the electrons or current flow.
Does Mitra argue this approach is cheap because it is cheap already? Or does his approach depend on the eventual development of much cheaper ways to produce nanotubes or buckyballs? Does anyone know what the state of the play is for creation of carbon nanomaterials on an industrial scale? If this stuff becomes cheap enough then it would not matter that the carbon bonds gradually break down due to UV light hitting them. One could just repaint surfaces every 7 or 10 years. Note that car and house paint can last that long and longer. Cheap photovoltaics will make mid day electricity much cheaper than late afternoon and evening electricity. We need dynamic electric pricing in order to use photovoltaic electricity efficiently. We have plenty of ways to shift our demand around in a 24 period or even between seasons in some cases. Cheap photovoltaics might lead electric intensive industries such as aluminum to shift the bulk of their processing to spring and summer and into areas such as Arizona which have the most sunlight. Using plastics to harvest the energy of the sun just got a significant boost in efficiency thanks to a discovery made at the Center for Polymers and Organic Solids at the University of California, Santa Barbara. Nobel laureate Alan Heeger, professor of physics at UC Santa Barbara, worked with Kwanghee Lee of Korea and a team of other scientists to create a new "tandem" organic solar cell with increased efficiency. The discovery, explained in the July 13 issue of the journal Science, marks a step forward in materials science. Tandem cells are comprised of two multilayered parts that work together to gather a wider range of the spectrum of solar radiation -- at both shorter and longer wavelengths. "The result is six and a half percent efficiency," said Heeger. "This is the highest level achieved for solar cells made from organic materials. I am confident that we can make additional improvements that will yield efficiencies sufficiently high for commercial products." He expects this technology to be on the market in about three years.
Heeger co-founded Konarka Technologies a few years ago to commercialize his solar cells research. The press release isn't specific on this point but Konarka might be the company to watch on the subject of commercializing the technology. If Heeger's team can substantially raise the conversion efficiency and also cheaply manufacture solar cells with this design then solar photovoltaics could finally take off. Solar initially will cut into peak demand. But solar could also provide energy for transportation once cheap high capacity batteries for cars become available. MIT's Technology Review reports on progress in raising solar photovoltaic cell efficiency. The cell, which employs new "metamorphic" materials, is designed for photovoltaic systems that use lenses and mirrors to concentrate the sun's rays onto small, high-efficiency solar cells, thereby requiring far less semiconductor material than conventional solar panels. Last month Spectrolab published in the journal Applied Physics Letters the first details on its record-setting cell, initially disclosed in December, which converts 40.7 percent of incoming light into electricity at 240-fold solar concentration--a healthy 1.4 percent increase over the company's previous world-record cell. Other groups are developing promising cells based on the new type of materials, including researchers at the Department of Energy's National Renewable Energy Laboratory (NREL), in Golden, CO. The NREL researchers will soon publish results in the same journal showing that their NREL's designs are tracking Spectrolab's, improving from 37.9 percent efficiency in early 2005 to 38.9 percent efficiency today.
The Boeing subsidiary Spectrolab is keeping ahead of NREL. Are private sector workers more motivated or better funded? How about a hefty X Prize for the first group to exceed 50%, 51%, and so on? Combine higher efficiency with solar concentrators for lower cost. Cheap solar power anyone? Such high output may be just the beginning. Raed Sherif, director of concentrator products at Spectrolab, says there is every reason to believe that these metamorphic solar cells will top 45 percent and perhaps even 50 percent efficiency. Sherif says those efficiencies, combined with the vast reduction in materials made possible by 1,000-fold concentrators, could rapidly reduce the cost of producing solar power. "Concentrated photovoltaics are a relatively late entry in the field, but it will catch up very quickly in terms of cost," he predicts. (See "Solar Power at Half the Cost.")
Cheap solar power would favor a shift to electric cars. Combine cheap solar power with cheap, high capacity, and safe car batteries and market forces alone would make our environment much cleaner. We'd get cleaner air. But we'd also get cleaner water as the use of oil (leaks of which run off in rain) gradually dropped. Cheap solar power would also lower costs and therefore accelerate economic growth and raise living standards. Cheap solar power with high conversion efficiency would use probably two orders of magnitude less land to produce the same amount of energy as biomass produces. So cheap solar power would reduce the demand for land for biomass energy. That would reduce habitat loss, especially in tropical lands such as Brazil, Malaysia, and Indonesia. The rising price of oil and the expectation that oil production won't rise as fast as demand has powerfully concentrated many minds to look for alternative cheaper sources of energy. Cheap solar power is an achievable goal and I expect we will see it achieved by the 2020s at the latest. Kevin Bullis of MIT's Technology Review reports on a new solar photovoltaic technology developed by Pasadena California start-up Soliant Energy which lowers the cost of photovoltaic power by use of a compact roof-mountable solar concentrator design. Soliant has designed a solar concentrator that tracks the sun throughout the day but is lighter and not pole-mounted. The system fits in a rectangular frame and is mounted to the roof with the same hardware that's used for conventional flat solar panels. Yet the devices will likely cost half as much as a conventional solar panel, says Hines. A second-generation design, which concentrates light more and uses better photovoltaics, could cost a quarter as much. He says that a more advanced design should be ready by 2010. The Soliant design combines both lenses and mirrors to create a more compact system. Each module is made of rows of aluminum troughs, each about the width and depth of a gutter. These troughs are mounted inside a rectangular frame and can tilt in unison from side to side to follow the sun.
Existing solar concentrators are too large and complicated to mount on residential roofs. Due to my expectation that we'll see truly disruptive technologies come to market, I've long been skeptical of 50 and 100 year projections of carbon dioxide emissions from fossil fuels consumption. There's no way we are going to get out 30 years from where we are now without the development of a variety of technologies that make solar photovoltaics, wind, batteries, nuclear, and other non-polluting power sources much cheaper. This report above provides an example of how we can expect disruptive technologies to come out of entrepreneurial start-ups. The higher the price of oil gets the more energy technology innovation we are going to witness. We could speed up the rate of innovation by taxing fossil fuels or by government funding of more energy research. I prefer the latter approach over the former because I think it would require less cash shifted through government hands. Better a $10 billion a year research budget than several hundreds of billions per year of green taxes. The ability to use solar power to generate liquid carbon-based fuels has the potential to generate energy for transportation much more efficiently than biomass, without biomass's water limitation, and with a much smaller land footprint. With all that in mind, some UCSD researchers have used solar power to partially reduce carbon dioxide. Chemists have shown that it is possible to use solar energy, paired with the right catalyst, to convert carbon dioxide into a raw material for making a wide range of products, including plastics and gasoline. Researchers at the University of California, San Diego (UCSD), recently demonstrated that light absorbed and converted into electricity by a silicon electrode can help drive a reaction that converts carbon dioxide into carbon monoxide and oxygen. Carbon monoxide is a valuable commodity chemical that is widely used to make plastics and other products, says Clifford Kubiak, professor of chemistry at UCSD. It is also a key ingredient in a process for making synthetic fuels, including syngas (a mixture largely of carbon monoxide and hydrogen), methanol, and gasoline.
A method to attach hydrogens to the carbon, totally displacing the oxygen, would produce hydrocarbons. Hook them up into long enough chains and the hydrocarbons become liquid at room temperature. Then you can put it in a gas tank and cruise. A cheap method to use of solar power to create chemical feedstocks and liquid fuels would solve one of solar's biggest problems: the sun does not always shine. We could use nuclear power as baseload electric power. Then use solar power to create liquid fuels. That could entirely break our dependence on fossil fuels. Given a sufficiently advanced and cheap enough battery technology we could use solar or nuclear power to charge batteries for transportation. But batteries are not the only potential way to use solar power for transportation. Solar power could run chemical processes to produce liquid fuels too. If we could produce all our liquid hydrocarbon fuels from carbon dioxide extracted from the atmosphere then burning of liquid hydrocarbons would no longer increase atmospheric carbon dioxide. Instead we'd have an artificial carbon cycle in parallel with the natural carbon cycle. Here's a big advance in solar photovoltaic technology: ST. LOUIS, Dec. 06, 2006 -- Boeing [NYSE: BA] today announced that Spectrolab, Inc., a wholly-owned subsidiary, has achieved a new world record in terrestrial concentrator solar cell efficiency. Using concentrated sunlight, Spectrolab demonstrated the ability of a photovoltaic cell to convert 40.7 percent of the sun's energy into electricity. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colo., verified the milestone. Note the use of the term "concentrator". Sounds like they are focusing light down from larger to smaller areas. So does the photovoltaic cell achieve 40% efficiency even with more intense concentrated light? Sounds like it. "This solar cell performance is the highest efficiency level any photovoltaic device has ever achieved," said Dr. David Lillington, president of Spectrolab. "The terrestrial cell we have developed uses the same technology base as our space-based cells. So, once qualified, they can be manufactured in very high volumes with minimal impact to production flow." High efficiency multijunction cells have a significant advantage over conventional silicon cells in concentrator systems because fewer solar cells are required to achieve the same power output. This technology will continue to dramatically reduce the cost of generating electricity from solar energy as well as the cost of materials used in high-power space satellites and terrestrial applications. They think they can increase the conversion efficiency even higher. "These results are particularly encouraging since they were achieved using a new class of metamorphic semiconductor materials, allowing much greater freedom in multijunction cell design for optimal conversion of the solar spectrum," said Dr. Richard R. King, principal investigator of the high efficiency solar cell research and development effort. "The excellent performance of these materials hints at still higher efficiency in future solar cells."
So how far will this drive down the cost of photovoltaic electricity? Projections made on the future use of various source of energy are guesses. Go out enough years and unpredictable technological breakthroughs make all future projections wrong. Maybe battery breakthroughs will make electric cars practical for most uses. Maybe photovoltaic breakthroughs will halt the growth of coal for electric power. Or maybe nuclear power will replace coal as the whole world becomes too concerned by the growth in carbon dioxide emissions. Then again, maybe methods to capture all pollutants and equester carbon dioxide from burning coal will get so cheap that coal will become the cheapest way to get clean energy. The problem with technologies that make fossil fuels cleaner is that they almost always cost more than not using such technologies. We are more assured of a cleaner environment if innately cleaner energy technologies become cheaper. MIT's Technology Review has an interesting report on how MIT graduate student Matthew Orosz, while on a Peace Corps trip to Lesotho in southern Africa, saw Africans using a parabolic reflector to bake bread. Building on this idea Orosz came up with a way to use common parts to make a solar electric generator that is cheaper than photovoltaics. The basic design of Orosz's solar generator system is simple: a parabolic trough (taking up 15 square meters in this case) focuses light on a pipe containing motor oil. The oil circulates through a heat exchanger, turning a refrigerant into steam, which drives a turbine that, in turn, drives a generator. The refrigerant is then cooled in two stages. The first stage recovers heat to make hot water or, in one design, to power an absorption process chiller, like the propane-powered refrigerators in RVs. The solar-generated heat would replace or augment the propane flame used in these devices. The second stage cools the refrigerant further, which improves the efficiency of the system, Orosz says. This stage will probably use cool groundwater pumped to the surface using power from the generator. The water can then be stored in a reservoir for drinking water.
Since the parts are mass produced for automobiles they are half the cost of photovoltaics for generating electricity. As a result, the complete system for generating one kilowatt of electricity and 10 kilowatts of heat, including a battery for storing the power generated, can be built for a couple thousand dollars, Orosz says, which is less than half the cost of one kilowatt of photovoltaic panels.
But does that cost estimate include maintenance costs and replacement parts? I'd expect a much higher mean time between failure for photovoltaics. Though when this gadget fails people with fairly common auto mechanic skills would be able to fix most of it and they'd be able to get many of the parts from an auto parts store. There's a downside to the mass-produced parts: It is unlikely that many of these parts could be made much cheaper. The design is not as amenable to cost reduction as photovoltaics. Eventually photovoltaics will drop in cost below the cost of this system. Still, it is a pretty neat idea today. Some questions: How much heat and electricity would this device generate in winter? Would the cold air prevent it from working? Also, can the heat do anything useful in the summer? Solar hot water comes to mind. Another question: How noisy is it?