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Alternative Energy Sources: Solar Gains Efficiency

Posted on: Tuesday, 10 April 2007, 15:00 CDT

By Bob Keefe

Just as computers, cars and satellite dishes have shrunk in size and improved in efficiency over time, so have solar electricity systems.

Today, photovoltaic "tiles" that blend in with a home's roof can provide 20 percent to 50 percent more power per square foot than the big rectangular boxes of a few years ago.

That means instead of taking every inch of a roof to generate enough electricity to help power a home, today's solar tiles can do it in about 200 square feet.

Even more improvements are coming in efficiency, aesthetics and costs.

In early March, the U.S. Department of Energy awarded $168 million in grants for research projects designed to help improve solar technology and make solar power just as cheap as other sources of electricity within a few years. The grants were part of the Solar America Initiative that President Bush announced last year to help wean the country from foreign oil.

Georgia Tech's University Center of Excellence for Photovoltaics, which has done groundbreaking work in solar electric systems, is getting some of the new research money.

Among the projects that will receive grants:

--Atlanta-based GE Energy, Georgia Tech and North Carolina State University, along with other partners, received $8.1 million to research ways to develop new high-efficiency silicon cell technologies.

--BP Solar, also working with Georgia Tech, the University of Central Florida and others, won a $7.5 million grant to explore ways to reduce the size of silicon wafers for solar panels.

--Konarka, a private company, and its academic partners got $1.2 million to research extremely low-cost solar cells that use organic dyes to convert sunlight to electricity.

--PowerLight, the leading maker of solar tiles, was awarded $2.8 million to study ways to reduce production costs through factory and design improvements.

Several companies were awarded grants to research ways to improve "thin-film" solar products, in which solar cells are essentially embedded into flexible sheets of plastic that can be used in a variety of ways.

Other companies are working on new technologies on their own.

In Iowa, for instance, thin-film solar company PowerFilm Inc. got its start making flexible solar chargers for electronic devices. Today, it also markets tents made from its solar films designed for use by the military or emergency responders.

Now, the company is working on ways to embed its films into metal roofs for houses or commercial buildings, architectural "fabrics" that can be used for roofing, and giant thin-film solar sheets that can be used to cover a rooftop like a piece of plastic wrap.

For now, the costs of such products are still a hurdle, acknowledged PowerFilm Chief Operating Officer Mike Coon. But with time and research, he said, prices will come down.

"What we're working toward is something that can be very mainstream but also low-cost," Coon said. "In the long term... one could imagine putting this down on an entire roof."

SOLAR POWER UPDATE

85 percent: Decrease in the price of solar cell modules between 1982 and 2006.

72 percent: Increase in shipments of photovoltaic systems between 2004 and 2005.

33 percent: Increase in grid-connected U.S. solar installations last year.

59 percent: Percentage of solar installations in the past five years that were tied to conventional public electricity grids.

40 to 60 percent: Typical decrease in monthly home energy bills using a standard-sized home solar energy system.

11 to 15 years: Time it takes for a typical home solar energy system to pay for itself. (Depends on size, location, availability of government rebates and tax credits.)

Sources: Solarbuzz.com, U.S. Energy Information Administration, California Public Utilities Commission

STATE INCENTIVES FOR SOLAR

A typical home solar electricity system can cost $25,000 or more, but federal and state incentives can bring the cost down substantially. In addition to a nationwide $2,000 federal tax credit currently available, many states and local governments are offering or considering other tax breaks for solar installations. Among them:

CALIFORNIA

A $3.4 billion program started this year is the nation's biggest and most far-reaching solar program ever. Incentives decrease over 10 years, but currently, the state will pay $2.50 per watt for new home solar installations. Coupled with federal tax credits, that would cover about 50 percent of the cost of a typical home installation.

NEW JERSEY

A $273 million, four-year program offers rebates of as much as 70 percent for solar equipment and low-interest loans for some purchasers. More than 2,000 homeowners have taken advantage of the program so far; thousands more are on a waiting list.

FLORIDA

The state started a $2.5 million rebate program last year that pays up to $20,000 for solar photovoltaic systems, $500 for solar water heaters and $100 for thermal pool heaters. The program is supposed to last until 2010 but depends on future funding.

TEXAS

Bills pending in the state legislature would give rebates of $4.50 per watt for homeowners and other incentives for commercial and industrial users. The program would be funded by a state surcharge on electricity bills that would cost an average user about 65 cents per month. In Austin, the municipal electric company also offers rebates of up to $4.50 per watt, equivalent to about $4,500 for a small system.

NORTH CAROLINA

Bills pending in the legislature would make the state the first in the Southeast to mandate that a portion of its energy supply come from renewable sources such as solar.

PENNSYLVANIA

Gov. Edward Rendell's "Project Sunshine" proposal would provide $200 million in solar rebates, funded by a state surcharge that would add about 45 cents per month to average users' power bills.

Sources: States, PV Now, North Carolina Solar Center

Source: The Atlanta Journal and Constitution

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