Shade for the cars, power for the people, at SMUD's airport photovoltaic system. The 390-foot array shades 75 cars and makes 130,000 watts of electricity on a sunny day, enough power for 52 homes.
Courtesy of Utility PhotoVoltaic Group
The ongoing PV price reduction is coming just in time to renew interest in renewable energy. Aside from hydroelectric power, which supplies 10 percent of grid-connected electricity, renewable energy now has little impact in the United States. Combined, biomass, garbage, geothermal, solar and wind contribute less than 1 percent of total U.S. energy usage.
And as the energy crises of the 1970s recede into the past, "annual renewables electric capacity additions have fallen to between 200 MW (million watts) and 300 MW during the 1990s from a level of more than 1,000 MW during the late 1980s." So says the Department of Energy.
The total contribution of renewables is projected to increase by 1.8 percent per year through 2010, again according to the DOE.
SMUD in your eye
In making its announcement, Sacramento Municipal Utility District (SMUD) was continuing a dramatic about-face that began when the utility closed its only nuclear reactor in the 1980s. Since then, SMUD, the fifth-largest publicly owned utility in the nation, has focused on getting new power from conservation and renewables. It already gets 5.7 megawatts from solar panels, and fully 420 rooftop PV systems are in place on houses and churches. Solar electricity is so popular that these installations are subsidized by customers who volunteer to pay a few dollars a month extra under a "green pricing" scheme.
But by the time the contract expires in 2002, green pricing should be obsolete in Sacramento. SMUD expects the new panels to produce electricity for just 8 to 10 cents per kilowatt-hour -- about what its residential customers pay today.
The $22-million contract had two parts: $19.3 million goes to a New Jersey firm, Energy Photovoltaics, Inc., which will produce the solar cells. Another $3 million will go to Trace Engineering of Seattle, for inverters that convert direct current from the solar cells into the alternating current used in homes and utility systems.
The district will also buy 150,000 watts worth of PV shingles, enough for 50 new homes. Shingles are a natural for exploiting sunlight, says Donald Osborn of the utility district. They catch a lot of sun, and, when placed on new houses, they reduce the need for regular roofing, and thus effectively reduce the price of PV installation. Finally, the utility has put up 130 kilowatts' worth of solar panels that also shade parked cars at the sun-baked Sacramento airport.
When did they first figure out that the sun could make juice?
