Solar Cells Info

By LAUREN MAYK
December 25. 2006
Source: Florida Herald Tribune
http://www.heraldtribune.com/apps/pbcs.dll/article?AID=/20061225/BUSINESS/612250336/1006/SPORTS

SARASOTA COUNTY — By next spring, a structure in Rothenbach Park is expected to produce enough energy to power 44 homes. Considering the several million customers that Florida Power & Light serves, that’s not a lot of juice.

But the solar project FPL is building east of Sarasota — on Bee Ridge Road, east of Interstate 75 — is still expected to be the largest solar array in Florida, covering half the size of a football field with panels about 5 feet by 3 feet each. It is being built to hold up FPL’s end of the bargain with customers who have signed up for its Sunshine Energy program. About 28,000 folks so far have agreed to fork over another $9.75 per month on their power bills to pay for power generated by renewable fuels such as wind and sunlight.

FPL has said it would buy renewable energy from another company, plus bring 150 kilowatts of solar power online for every 10,000 customers who join the program. This 250-kilowatt power producer gets the company more than two-thirds of the way to meeting its self-imposed requirement.

The array will cost between $1 million and $2 million — a fraction of the cost of building a natural gas or coal plant. But it will also produce just a small sliver of the energy that one of these bigger, more complicated and expensive plants spits out.

Solar projects are generally less cost-effective than bigger plants using other fuels, costing more per watt of electricity. But solar proponents say there may be benefits to solar power than can’t be measured in dollars and cents.

“How do you count the avoided cost of air pollution and water pollution?” asked Philip Fairey, deputy director of the Florida Solar Energy Center, part of the University of Central Florida in Orlando.

Plus, solar projects can reduce the exposure to higher fuel prices in the future. Building more of these solar projects and spreading them out in different parts of the state could make the grid more efficient, Fairey said. By using large power plants like the one in Parrish to produce energy, power companies have to send their products long distances using a series of transmission and distribution lines.

But by dotting the landscape with more — albeit smaller — power-producing engines, energy would likely be used by the homes and businesses close to those sources. “The farther power has to travel down the grid, the more energy you lose,” Fairey said. That is not a problem the Oakland Ice Center in California, where panels like the ones chosen for the Sarasota solar project have already been installed.

There, power from the 1,960 panels on the rink’s roof is used by the ice center itself instead of going back into the grid. The solar array, which covers about 25,000 square feet, would otherwise produce enough electricity for 370 homes. “Even that only brings us to 30 percent of the power we’re using,” said Dave Fies, general manager of the Oakland Ice Center.

The panels are expected to more than pay for themselves, though, with an annual energy savings projected to be $137,000. The annual loan payment on the array is $126,000, leaving another $11,000 on the table.  There have been a few glitches with the venture, which was paid for by the city of Oakland as part of a larger project incorporating solar panels on six buildings.

For example, Oakland saw 7 percent less sunlight than expected last year, which meant the center saved less than it had anticipated.  Unlike projects like Oakland’s that require a rooftop, the 1,200 photovoltaic panels in Sarasota will be mounted on the ground, utilizing the covered landfill. They will lie flat, mounted about 4 to 6 inches above the ground.

The placement and angle of the panels is important in Florida, where these large panels have to be protected from strong winds and hurricanes. The Sarasota County project will use panels that were originally designed for roof arrays because they are “even more wind resistant,” said FPL spokeswoman Pat Davis.

The panels contain silicon, with which the sun reacts to produce energy. A layer of glass protects it on top and a neutral material supports it below. When sunlight hits the panels, it creates a flow of DC, or direct current, electricity.

That kind of electricity works like the battery in a cell phone, and needs to be converted into AC, or alternating current, electricity. When you charge up your cell phone, the box at one end of the cord that plugs into the wall acts as the inverter.

In the case of the solar array, the inverter is located between the park and Bee Ridge Road. An underground cable carries the power to a pole on Bee Ridge Extension, where the energy flows into the larger power grid.