Making a Solar Cell Component without Using Fossil Fuels

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PETROLEUM FREE?: A new backsheet for solar cells, seen at work here, is made from cotton and castor beans rather than petroleum-based plastics.

Cleaner than clean energy: BioSolar creates new plastic backing for photovoltaic cells out of cotton and castor beans rather than petroleum products

By David Biello

Solar energy is touted by some as the solution to the world's energy woes. But the process of making the various components requires fossil fuels, both for power and for the components themselves, some of which are based on petroleum.

A new company, BioSolar, aims to kick petroleum to the curb, at least in the realm of building solar photovoltaics, cells of crystalline silicon that turn sunlight into electricity. Such photovoltaic cells rely on conventional plastic polymers to provide a protective backing, also known as backsheets. Those plastics are made from—you guessed it—petroleum.

"It's renewable and you don't use any petroleum," says electrical engineer David Lee, president and CEO of the California-based company about the new product. "The real merit is that we can actually reduce the cost of the backsheet compared to conventional petroleum-based backsheet." Lee claims their backsheets will cost 25 percent less than conventional backsheets, which cost between $0.70 and $1 per square foot.

Already, such backsheets are rising in price, thanks to the recent run-up in world oil costs, at a time when the solar industry is trying to bring down costs to make their technology more competitive with other forms of power generation, such as cheap, plentiful and extremely polluting coal.

BioSolar starts with used cotton rags and turns them into a film of cellulose, a natural fiber. They then blend this film with a type of nylon made from castor beans by Philadephia-based Arkema, Inc. to make the so-called BioBacksheet. Initial testing by the company at the National Renewable Energy Laboratory shows that this flexible plastic backsheet lasts as long or longer than conventional ones, and keeps out just as much moisture.

In addition to keeping away from petroleum plastics, BioSolar also claims not to be using any genetically modified crops in its product—a further boost to its green credibility. But nearly 90 percent of the U.S. cotton crop is so altered, either to resist insects, herbicides or both, according to the U.S. Department of Agriculture. And cotton cultivation still requires tons of pesticides and fertilizers, both of which are derived, in part, from petroleum.

Regardless, if the cotton and castor-based backsheet proves cheaper than the petroleum version it may help remove a bit more fossil sunshine from the new solar energy. "Our goal is to replace all the petroleum plastic out of the solar cells with this bio-based one," Lee says.

http://www.sciam.com/article.cfm?id=making...out-fossil-fuel

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California plans on building 2 plants that peak at 800 megawatts

http://www.nytimes.com/2008/08/15/business...interstitial?hp

Two Large Solar Plants Planned in California

Companies will build two solar power plants in California that together will put out more than 12 times as much electricity as the largest such plant today, a fresh indication that solar energy is starting to achieve significant scale.

The plants will cover 12.5 square miles of central California with solar panels, and in the middle of a sunny day will generate about 800 megawatts of power, roughly equal to the size of a large coal-burning power plant or a small nuclear plant. A megawatt is enough power to run a large Wal-Mart store.

The power will be sold to Pacific Gas & Electric, which is under a state mandate to get 20 percent of its electricity from renewable sources by 2010. The utility said that it expected the new plants, which will use photovoltaic technology to turn sunlight directly into electricity, to be competitive with other renewable energy sources, including wind turbines and solar thermal plants, which use the sun’s heat to boil water.

“These market-leading projects we have in California are something that can be extrapolated around the world,” Jennifer Zerwer, a spokeswoman for the utility, said. “It’s a milestone.”

Though the California installations will put out 800 megawatts at times when the sun is shining brightly, they will operate for fewer hours of the year than a coal or nuclear plant would and so will produce a third or less as much total electricity.

OptiSolar, a company that has just begun making a type of solar panel with a thin film of active material, will install 550 megawatts in San Luis Obispo County. SunPower Corporation, which uses silicon-crystal technology, will build about 250 megawatts at a different location in the same county.

The scale is a leap forward. Thomas H. Werner, the chairman of Sunpower, said that the 250 megawatts his company would build was as much solar photovoltaic capacity as was installed worldwide last year.

“If you’re going to make a difference, you’ve got to do it big,” said Randy Goldstein, the chief executive of OptiSolar. The scale of the two plants will “bring a new paradigm to bear” for the industry, he said.

At 800 megawatts total, the new plants will greatly exceed the scale of previous solar installations. The largest photovoltaic installation in the United States, 14 megawatts, is at Nellis Air Force Base in Nevada, using SunPower panels. Spain has a 23-megawatt plant, and Germany is building one of 40 megawatts. A recently constructed plant that uses mirrors to concentrate sunlight, called Nevada Solar One, can produce 64 megawatts of power.

Solar power remains expensive compared to generating electricity from coal or natural gas, but it is bounding ahead, driven by quotas set by the states. California’s 20 percent renewable standard is one of the toughest, and companies there are afraid they will miss a 2010 deadline. Pacific Gas & Electric expects that when the new plants are completed its total will rise to 24 percent, but that will not be until 2013.

Both plants require numerous permits, and plans could still go awry. The companies involved said they expected that building gargantuan plants would achieve economies of scale in the cost of design, installation and connection to the electric grid.

The companies said they were forbidden by contract terms to talk about price, and a spokeswoman for Pacific Gas & Electric said her company was trying to obtain the best possible deal for ratepayers by not telling other suppliers of renewable energy what it was willing to pay. But all three companies said the costs would be much lower than photovoltaic installations of the past.

SunPower’s panels are mounted at a 20-degree angle, facing south, and pivot from west to east over the course of the day to keep facing the sun. OptiSolar’s are installed at a fixed angle. They are larger and less efficient, but also much less costly, so the cost per watt of energy is similar, company executives said.

Both are good at producing power at a time of day when the prices tend to be high, in the afternoon.

Neither approaches the economy of fossil-fuel burning plants, said Ms. Zerwer, the spokeswoman for Pacific Gas & Electric. But they will be competitive with wind power and with power from solar thermal plants, which are equipped with mirrors that use the sun’s heat to boil water into steam. And prices will fall, she predicted.

Her company, she said, was “going to contribute to the virtuous cycle of technology innovation and lower unit manufacturing cost, by purchasing on such a scale.”

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Related to this..

California plans on building 2 plants that peak at 800 megawatts

That's a step in the right direction, although I wish that homebuilders would look towards designing homes that can produce their own energy without being connected to a grid. It'd be a much more efficient way of handling that energy.

Imagine one day if we have hydrogen fueled cars - and solar powered homes, where technically, your home could provide enough energy for your household needs plus the fuel for your car.

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Related to this..

California plans on building 2 plants that peak at 800 megawatts

That's a step in the right direction, although I wish that homebuilders would look towards designing homes that can produce their own energy without being connected to a grid. It'd be a much more efficient way of handling that energy.

Imagine one day if we have hydrogen fueled cars - and solar powered homes, where technically, your home could provide enough energy for your household needs plus the fuel for your car.

I am headed that way, depending on where I live. If I stay in California, definitely solar. I talked to the project manager of a very large solar project for a major company (was working for them at the time), and his estimates were, for an average size house, approximately 30,000 for the panels and a battery, with a 10-30 year warranty and 7+ years until I started seeing any sort of return investment, based upon the sky-high energy costs here in the Bay Area.

If I move to Canada (likely Saskatoon, Regina, or Moose Jaw), not so sure..

Edited August 15, 2008 by SRVT

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Related to this..

California plans on building 2 plants that peak at 800 megawatts

That's a step in the right direction, although I wish that homebuilders would look towards designing homes that can produce their own energy without being connected to a grid. It'd be a much more efficient way of handling that energy.

Imagine one day if we have hydrogen fueled cars - and solar powered homes, where technically, your home could provide enough energy for your household needs plus the fuel for your car.

I am headed that way, depending on where I live. If I stay in California, definitely solar. I talked to the project manager of a very large solar project for a major company (was working for them at the time), and his estimates were, for an average size house, approximately 30,000 for the panels and a battery, with a 10-30 year warranty and 7+ years until I started seeing any sort of return investment, based upon the sky-high energy costs here in the Bay Area.

That's not bad considering how much homeowners will pay to have a custom pool put in. I'm confident that the overall costs will go down significantly within the next 5 years...provided there are enough tax incentives for homeowners to invest. My parents were the first ones in our neighborhood to have a solar water heater installed on our roof - this was back in about 1976, during Carter's Administration. They took advantage of a tax credit that Carter had put in place. Within the year, at least a dozen of the neighbors had also installed solar water heaters on their roof. Then Reagan cut the tax program and nobody was buying them anymore.

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If I move to Canada (likely Saskatoon, Regina, or Moose Jaw), not so sure..

Up there you could do a combination solar and wind. And if you have a body of water on your property, hydro.