|
www.times.org
Capturing solar’s unlimited potential Projects big and small trigger a wave of solar projects
A wave of unprecedented solar power development activity is sweeping the Northwest, spurred by utilities that are promoting it to their customers. According to Renewable Northwest Project, solar energy offers more potential than any other renewable resource in the region. The Portland-based group estimates the potential supply is greater than 200,000 average megawatts. But so far, solar power projects are distinguished from other energy sources by their small size. The City of Ashland, for instance, produces 30 kilowatts of solar power at four locations: the Southern Oregon University Library, Ashland Post Office, the Oregon Shakespeare Festival and the Ashland Civic Center. Financial support from the Bonneville Environmental Foundation have made this and several similar projects possible. A recent Renewable Northwest Project survey shows that 16 utilities are selling “green power” to about 18,600 homes and businesses, paying premiums ranging as high as $50 per month for the service. While the Oregon Office of Energy sees this trend continuing, it doesn’t foresee the development of largescale solar power stations, like the vast photovoltaic solar farms in the Mojave Desert. “Large-scale solar-thermal power generation is not practical or economical anywhere in Oregon,” the agency says on its web site. Maybe the folks at the energy office should meet David Slawson. He says making electricity from solar power is about as simple as using a magnifying glass to fry an egg on the sidewalk, and experts at the U.S. Department of Energy seem to agree with him. In the 1980s, Slawson was owner of a massage school in Portland, the East-West College of the Healing Arts. He bought a home in the southeast part of the city, moving in from rural Clackamas County. “I became very aware of car fumes, mixed with diesel bus fumes,” he says. “It seemed like a river of air pollution.” Soon he found himself at the local library investigating a web of interrelated problems: global warming, air toxics, deforestation. “I came across a book called the Phoenix Project – solutions for global warming, ozone depletion, urban pollution and acid rain: A transition to a renewable energy policy.” He read it twice and called the author. He became convinced that the best solution was to make fuel from the sky. “The only way to hedge against the future volatility in the electrical marketplace is to correct this imbalance of energy options by building 20 to 50 percent of the energy mix into renewable based electrical power generation sources,” he says. “It can be easily done if we get the political will.” But how? He discovered an under-used technology known as “concentrating solar power,” or CSP. A CSP dish consists of a field of mirrors that reflect sunlight back to a focal point. Behind the focal point are tubes of hydrogen that, when heated, expand to turn a turbine. Demonstrations of the technology have been producing electricity at the University of Nevada-Las Vegas and at a Boeing research facility in Huntington Beach, Calif. Next year new demos will be installed in South Africa, Spain and Italy. The federal government has provided $6 million in funding for 40 additional plants. Just how much energy does Slawson think he can produce? “Just 30 minutes of sunshine would provide the world with 100 percent of its energy needs for a year,” Slawson says. A few comparisons illustrate the potential. A CSP unit can produce three times as much electricity per square meter than a traditional photovoltaic installation. (Photovoltaics is the direct conversion of sunlight into electricity, using semiconductor materials in solar panels.) A 250-kilowatt CSP plant composed of ten 25-kilowatt dish/engine systems requires less than an acre of land. (A photovoltaic system uses about 5 acres for each megawatt of installed capacity.) A 10.8 square mile CSP facility can generate as much power as Hoover Dam and reservoir, which covers 257 square miles of landscape while flooding the Colorado River. Considering the land required for mining, concentrating solar power plants also use less land than coal power plants, according to the U.S. Department of Energy. The technology can also produce hydrogen for fuel cells. A 100-square mile facility could displace all the fossil fuel burned in the United States for transportation. The Department of Energy estimates that as many as 20,000 megawatts of concentrated solar power could go online in the Southwest by 2020, including potential sites that extend into the southeast corner of Oregon. Since the sunlight is free, the initial capital expenditure for the collectors is equivalent to buying a lifetime supply of fuel. To recover this high first cost, plant operators need to be able to sign long-term power purchase agreements. However, the current environment favors low first-cost, gas-powered plants, with ratepayers bearing the risk of escalating fuel costs. “That’s an over-dependency on a single supply source, and a setup for future volatility,” Slawson says. Concentrating solar power technologies can employ cost-effective thermal storage, which sets aside the accumulated heat energy for later conversion to electric power. These plants can generate electricity even when the sun isn't shining, at night or during cloudy weather. Concentrating Solar Power is on the brink of commercial viability, and U. S. industry is actively seeking commercial projects. |