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solar energy

Page history last edited by Brian D Butler 11 years, 10 months ago


Solar Energy


    see also:  Renewable and alternative energy  ,    Clean-tech and environmentally conscious investing ,   energy industry , Environment issues


In spite of excess supply in much of the South West USA, the sun has remained a relatively unused source of electricity.   In California's Mojave desert, there is the world's largest solar farm, with some 400,000 mirrors covering 4 square miles, which generates some 354 megawatts of electricity (enough to power close to a million homes).   This power plant was built in the 1980s, and no others have been built since...until now.


Why now?

  1. federal tax credits
  2. increased federal funding for R&D in renewable energy
  3. states passing new standards requiring renewable energy
  4. public distaste for "dirty" energy, such as coal (greenhouse gas issue)


Main technology being explored?

  1. CSP - Concentrating solar power:  focus suns rays using mirrors onto one spot...use heat to a fluid that is used to drive a turbine.
    • Benefits:  power can be stored in heat, so it is available at night, and on clowdy days
      • no CO2 (carbon dioxide) emissions.  (no global warming)
      • plenty of sun in desert , probably enough to power the entire country
    • Drawbacks: 
      • expensive compared to coal
  2. photovoltaic -  lets light interact directly with the semiconductor to make power. (not popular for industrial projects (more for homes)
  3. direct currents - as opposed to alternating currents, are seen as the key to unlocking the storage and delivery of more energy efficient systems such as solar.



Rooftop solar panels for the home


Due to changes in regulations in the US, there is now an opportunity for individuals to generate excess electricity, and to sell that excess electricity back to the power company.  With this opportunity, there has been a trend we are seeing of electrical companies investing 100's of millions of dollars to improve the solar panel designs, and to integrate this potential into their grids.  As opposed to wind technology, they see this as having real potential.   see related article here 


New Plants

New CSP plant in Nevada (2007) :  capacity =  64 megawatts (tiny, compared to national needs)

Other investments (by 2020) should increase US capacity to 7,000 megawatts (still tiny compared to national needs)


Nations energy needs for Electricity:  1 million megawatts +



International Investment:

international CSP companies are investing in the USA: 

  • Acciona Energy of Spain,
  • Abengoa of Spain
  • Solel of Israel



Changing Economics of Solar Energy


The cost of coal is still much cheaper than the cost of solar energy, but these new firms are anticipating, and betting on a changing regulatory environment that may make solar energy more profitable  They are essentially betting the curve:


Current costs:

  • Coal:                        2-3 cents per kilowatt hour (kwh)
  • CSP solar (today)  17 cents / kwh


Expected future costs

  • CSP solar (future)  9-10 cents / kwh   (as technology improves ...with federal funding of research, + private research, trend)
  • coal:                          rising.  



Why might the cost of Electricity from Coal rise in the future?

  • These companies are betting that the cost of coal will rise sharply in the near future if the US government decides to impose a tax on the electricity generated in this "dirty" way. 
  • regulation factors into the environmental costs of producing with Coal.
  • watch for foreign pressures, especially as the global warming debate heats up!
  • also watch Senator Harry Reid, Democrat from Nevada who is fighting to prevent any and all future coal plants in Nevada, and nationwide.



Solar power may not find large-scale success — At least in its current form, says the American Scientist Online. The power required to manufacture photovoltaic equipment may make it difficult to scale installations quickly enough to satisfy global power demands. However, an upcoming technology called dye-sensitized cells may be cheap enough to solve an early production crunch. Check out the original article for more.




Industry Summary



What could be more appealing than generating usable electricity from everyday sunshine? Ever since scientists at the famed Bell Laboratories first demonstrated the solar cell in 1954, solar power has been seen as one of the most desirable, if elusive, means of creating electricity or heat. Solar power accounted for about 5,000-megawatts, or 0.15% of all energy consumed in the world during 2006. The ratio will show slow but steady growth thanks largely to interest in solar power at city governments, such as the City of San Francisco, California, and in governments such as those belonging to the European Union.
Photovoltaics: Traditionally, photovoltaic (PV) technology is based on layers of silicon within panels that have been engineered to attract the sun’s rays and create a flow of electric current to electrodes.  Currently, solar generation equipment is too expensive to compete with conventional generation. However, immense amounts of effort and venture capital are being invested in solar technology, both in the U.S. and abroad, and significant progress is being made at the laboratory level. Solar power could begin to become reasonably competitive by to 2015. The industry’s goal is to greatly increase the efficiency and output of solar cells. Current PV technology converts about 15% of available sunlight into electricity with crystalline cells, and only about 10% in less expensive thin-film cells.  (Thin-film can offer advantages in some installations, such as rooftops, because it is lighter in weight.) High efficiency is even more important when you consider the fact that peak sunlight is available only a limited part of the day.
The U.S. Department of Energy has an official goal, called the “Solar America Initiative” of making solar power costs competitive by 2015. Solar America is based on more than $137 million in yearly (2008) grants for research focused on improved technologies for PV manufacture and installation. By the end of 2007, the cost of PV cells had dropped to about $4.50 per watt for crystalline modules, and $3.60 for thin-film. These are retail prices. The Holy Grail is about $1.00 to 1.50 per watt, which would make PV very price competitive.  (Watts are measured at mid day peak output of the cell.)
Several advanced technologies for PV are under development. One such technology is concentrated photovoltaic (CPV) which uses mirrors, lenses or other items to concentrate and thus vastly increase the intensity of sunlight. Researchers at the University of Delaware set a record, in mid 2007, of 42.8% efficiency in a CPV cell. Their goal is to hit 50%. Shell and BP are also active in solar cell technology.
A leading manufacturer, Miasole, is doing research that it believes will increase thin-film’s efficiency to 15%, or about that of traditional crystalline. If this occurs, it may be a major breakthrough in terms of cost.  This is a dramatic reduction over the past couple of decades.
Additional big news for solar power comes in the form of plastic solar cells. Using a variety of techniques, many companies are beginning to print out solar cells on plastic sheets instead of silicon chips. A 2005 breakthrough uses nanotechnology to detect infrared energy, which is present even when the sun isn’t shining. Not only do these new cells promise to be cheaper than traditional photovoltaic cells, they are also more flexible, versatile and portable, able to conform to almost any surface, roll up for transport, or be integrated into laptops, cell phones and other portable electronics. Nanosolar, Inc. (www.nanosolar.com) secured $100 million in financing to build a facility that will be able to manufacture 200 million of these cells per year. 
Wal-Mart announced in 2007 that it is testing the use of solar panels for electricity needs at 22 stores in California and Hawaii. The firm’s hope is that PV can supply up to 30% of a store’s power needs. Likewise, retail chain Kohl’s is installing solar panels on California stores
Meanwhile, some consumers are willing to pay for solar installations despite high costs (around $40,000 per home). In the U.S., the number of new photovoltaic system installations in homes tripled from 2,805 in 2002 to 7,446 in 2006, according to the Interstate Renewable Energy Council, www.irecusa.org.
Global sales for the photovoltaic industry are rising about 25% per year, with the most marked growth in sales occurring in Japan and Germany, which have both made sustained and concerted pushes for solar technology. In 2005 alone, according to BP and the International Energy Agency, installed solar generating capacity grew by about 40% on a worldwide basis, to 3,704,758 Kilowatts. Consultants at Clean Edge forecast that the solar equipment market will be $30.8 billion in 2013. Growing demand has outpaced the supply of photovoltaic cells, and many manufacturers face huge backlogs of orders. Meanwhile, there is a shortage of the high quality silicon needed for the manufacture of PV cells.
European nations are setting world records for the size of its solar power plants. U.S.-based PowerLight Corporation created a 10-megawatt photovoltaic plant in Bavaria in 2004. Dubbed the Bavaria Solarpark, the system consists of 57,600 photovoltaic panels in three separate groups on 62 acres. Meanwhile, a 62-megawatt project has broken ground in Moura, Portugal. Called Girrasol, it will be more than six times the size of the Bavaria Solarpark. A municipal enterprise in Moura named Amper Central Solar, S.A. is the lead organization for the plant along with BP Solar. Girrasol is expected to be completed in 2010. SunEdison and SkyPower hope to build a 50 megawatt plant in Ontario, Canada. Zhonghao New Energy Investment of Beijing, China has the most ambitious project. It is proposing to build a plant with up to 100 megawatts capacity near Dunhuang City, China. Also, in South Korea, a massive 19.6 megawatt project was announced in mid 2007. To be constructed by Suntechnics, a subsidiary of Germany-based Conergy AG, the system will use 109,000 solar panels.
Solar Thermal (or “CSP,” Concentrating Solar Power): Solar thermal generation has truly exciting potential. A good example is “Stirling Dish” technology, manufactured by Stirling Energy Systems (www.stirlingenergy.com). This technology is based on large dishes that look somewhat like satellite television receivers. At 38 feet in diameter, these dishes are mounted on rotating stands that enable them to track the sun as it rises and falls during the day. Each dish, which is covered in flat mirrored panels, is connected to a Stirling Engine, which uses focused solar energy to heat hydrogen in a closed-loop system. Expanding hydrogen gas creates pressure on pistons within the engine, which turns at a steady 1,800 RPM. The engine powers an electric generator. Cost for the original prototype and engine was around $300,000, making the dish too expensive for use on a large scale. In recent months, however, Stirling has simplified its design using easily mass-produced dish frames, heat exchangers and mirrors resulting in a far more affordable $25,000 per dish system.
Stirling Energy received the approval by California state regulators in late 2005 for a 20-year power purchase agreement between Stirling and San Diego Gas & Electric Co. The approval is the green light for the construction of an enormous three square-mile solar generating station in Imperial Valley, California. Upon completion, the station will generate 300-megawatts, with an option to expand to 900-megawatts.
CSP is also used to heat fluids to extreme temperatures (up to 750 degrees Fahrenheit), which produces steam that then drives a turbine. A provider of this kind of solar power is Ausra, Inc. (www.ausra.com), which has commitments for 1,000 megawatts of solar power with Pacific Gas & Electric and Florida Power and Light by 2010.
A landmark project in California is the Mojave Solar Park, which is to be built in the Mojave Desert. When complete, the 6,000 acre will use 1.2 million parabolic mirrors and 317 miles of vacuum tubing to capture the sun’s heat, generating 553 megawatts of solar power, enough to support 400,000 homes in northern and central California. The park uses technology developed by Solel Solar Systems of Israel. PG&E, a major California utility, will be the major customer when the system comes on line in 2011.
Elsewhere, Spanish firm Acciona Energy opened a 64 megawatt plant using similar technology in Nevada in 2007. Projects like these are a major leg-up on California’s goal of requiring retail sellers of electricity to obtain at least 20% of their electricity from renewable sources by 2010 (with a goal of 33% by 2020).
According to Emerging Energy Research, more than 45 CSP projects with a combined capacity of 5,500 megawatts are in the planning stages worldwide, with four of those scheduled for completion by 2008 in the U.S. and Spain. Spain is especially suited to solar power generation due to its dry, sunny climate. Spanish solar firms of note include Abengoa Bioenergy and Acciona.
For the greatest efficiency, CSP can be combined with unique power storage technologies. For example, a system of heat storage based on pressurized water or molten salt allows energy to be captured for use in generation during evening hours.
Space Solar Power (SSP): First proposed in 1968 by then-president of the International Solar Energy Society Peter Glaser, collecting sunlight from a geostationary orbit high above the Earth enables the gathering of constant light that is eight times as strong as that on the ground. A solar panel on the orbiting structure would convert the light to electric current, which is then beamed to Earth by microwave to a specified antenna. The catch is that the final output, which is a measly few hundred watts per kilogram, is too low to justify the enormous costs related to such a project that was initially estimated to be $305 billion (in 2000 dollars). Since then, costs have fallen somewhat due to technological advances.
In May 2006, the University of Neuchatel in Switzerland announced a technique using a film created for use in space that yields power densities of 3,200 watts per kilogram. There is also interest in SSP in Japan, where the JAXA space agency has plans to launch a satellite that will spread into a sizable solar array capable of beaming 100-kilowatts of microwave or laser power to Earth by 2010.
Solar Updraft Towers: Yet another potential boon for solar power is a proposed renewable energy power plant that heats air in a large greenhouse, thereby creating convection that causes air to rise and escape through a tall, specially designed tower.  The upward-moving air drives electricity-producing turbines. Although there are no updraft towers in operation as of late 2007, there are projects on the drawing board in Australia, China, the U.S. and Spain. However, funding for such projects remains in question.
In Australia, for example, a 50-megawatt Tapio Station plant is under consideration that would feature a tower that is 1,600 feet tall and 260 feet in diameter. The tower would be surrounded by a two-mile diameter transparent canopy that will trap and heat air at ground level, which will naturally rise into the tower (which acts as a kind of vacuum). Inside the tower, wind is produced by the vacuum to power an array of turbines clustered around the tower. Proponents of the project, which is headed by Melbourne-based EnviroMission Ltd. (www.enviromission.com.au), hope to eventually power as many as 200,000 homes. Another plant with a tower that soars to half a mile is proposed for China. As of 2007, EnviroMission continued to seek development money.

Government Subsidies

More harm than good?   According to a recent econmist.com article, there is more harm being done by subsidies than good:

"LAST week, EDF, one of the world's biggest energy firms, announced it would invest $50m in a firm called Nanosolar, which aims to produce cheap solar panels. Nanosolar believes it can sell panels for a little as $1 for each watt of capacity—less than one-third of the best deals currently on offer. If true, that’s great news, especially since it would reverse a worrying trend.


It used to be an axiom that solar power grew steadily cheaper as time passed. Solar panels were once too expensive to install on anything but satellites. But as the technology improved, they became cost-effective, first in isolated spots such as weather stations and oilrigs, and later on lonely farms and houses far from the grid.


By 2004, solar panels were coming very close to generating power at the sorts of prices regular grid-connected customers pay in places where electricity is expensive, such as Japan. Enthusiasts confidently predicted that solar cells would soon supplant grimy old power plants, and spare the world the tiresome chore of digging for coal, uranium and natural gas.


Fans of solar power were so sure of themselves they came up with their own version of Moore’s law for the sun’s power, rather than that of computer chips. Every time the volume of solar cells produced around the world doubled, they predicted, the price per watt would fall by 20%. After all, it had done so reliably for the previous 40 years.


But in 2004, everything changed. Prices of fossil fuels began to climb, and worries over global warming and security of supply intensified. Those factors might have been enough to boost investment in solar by themselves. At any rate, the riches that undoubtedly await the first firm to create cheap solar power were already luring venture capital.


But governments such as Germany’s, who wanted to give solar and other forms of renewable power an extra boost, began subsidising wind turbines and solar panels in order to speed their adoption. This was supposed to have three benefits: it would reduce emissions of greenhouse gases, spawn a fast-growing and lucrative domestic industry, and help to lower the unit costs of solar panels, thanks to the bigger volumes. Indeed, the three goals are interdependent: solar power will have to be deployed on a massive scale if it is to make much of a dent in emissions, which will only be affordable if it becomes much cheaper.


But Germany’s subsidy, which takes the form of a generous tariff for solar power, has had the opposite effect. So many firms rushed to install solar panels in such profusion that the world ran short of the type of silicon used to make them. The price of silicon—and thus of solar panels—rose. Many firms began to pursue radical new panel designs, simply to reduce their silicon consumption.


Meanwhile, Germany has wound up with more solar panels than any other country in the world—a perverse result for such a cloudy place. It also has fewer wind turbines than it might otherwise—again, an odd outcome for a blustery country. The German government has decided that the subsidy is too expensive, and wants to revise it—just the sort of unpredictable behaviour that tends to alarm rather than entice investors.


Of course, Germany is not the only country that subsidises solar power, and such subsidies are not the only cause of inflation in the solar industry. Lots of silicon factories are under construction, so an end to the present bottleneck is in sight. Several firms like Nanosolar insist that their wares will soon be competitively priced without subsidies. And fossil fuels are also subsidised, insofar as their prices do not include the cost of the pollution they generate.


Moreover, tackling global warming is not necessarily an unreasonable use of taxpayers’ money. But that does not relieve governments of the obligation to get good value for money. Fans of California’s solar subsidy claim it will achieve similar results at a tenth of the price. Better still would be a hefty carbon tax, or a strict cap-and-trade regime, which would provide a boost to all low-carbon power sources, not just those that find favour with prodigal bureaucrats.





Industry News




Start-Up Sells Solar Panels at Lower-Than-Usual Cost


Published: December 18, 2007


SAN JOSE, Calif. — Nanosolar, a heavily financed Silicon Valley start-up whose backers include Google’s co-founders, plans to announce Tuesday that it has begun selling its innovative solar panels, which are made using a technique that is being held out as the future of solar power manufacturing.


The company, which has raised $150 million and built a 200,000-square-foot factory here, is developing a new manufacturing process that “prints” photovoltaic material on aluminum backing, a process the company says will reduce the manufacturing cost of the basic photovoltaic module by more than 80 percent.


Nanosolar, which recently hired a top manufacturing executive from I.B.M., said that it had orders for its first 18 months of manufacturing capacity. The photovoltaic panels will be made in Silicon Valley and in a second plant in Germany.


While many photovoltaic start-up companies are concentrating on increasing the efficiency with which their systems convert sunlight, Nanosolar has focused on lowering the manufacturing cost. Its process is akin to a large printing press, rather than the usual semiconductor manufacturing techniques that deposit thin films on silicon wafers.


Nanosolar’s founder and chief executive, Martin Roscheisen, claims to be the first solar panel manufacturer to be able to profitably sell solar panels for less than $1 a watt. That is the price at which solar energy becomes less expensive than coal.


“With a $1-per-watt panel,” he said, “it is possible to build $2-per-watt systems.”


According to the Energy Department, building a new coal plant costs about $2.1 a watt, plus the cost of fuel and emissions, he said.

The first Nanosolar panels are destined for a one-megawatt solar plant to be installed in Germany on a former landfill owned by a waste management company. The plant, being developed by Beck Energy, is expected to initially supply electrical power for about 400 homes.


The company chose to build its plant in southern San Jose, news that was cheered by local development officials. Much of the microelectronics industry created here has moved to Asia and new factories are a rare commodity in Silicon Valley.







Companies / Trends to Watch:





Humor Video about Solar Energy:





Resources & external Links




To find out more about solar power and the Solar America Initiative, visit the U.S. DOE, Solar Energy Technologies Program at
For excellent information on the photovoltaic industry, see Solarbuzz, www.solarbuz.com. The site includes a survey of solar cell prices, along with general news and resources




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