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Solar energy viable in Illinois under right conditions, data indicate

Eva Kingston, Illinois State Water Survey


CHAMPAIGN, Ill. — Although costs for photovoltaic technology are too high now in comparison with power supplied by traditional utilities, the potential to make solar power economically feasible exists on a smaller scale, according to data released today by the Illinois State Water Survey and the University of Illinois at Urbana-Champaign.

“Production costs of electrical power from the sun for typical Illinois residences or businesses currently cannot compete with power purchased from utilities but can become attractive for remote locations or if subsidies and tax breaks are available,” said Bob Scott, a meteorologist with the water survey who has been studying the issue with Angus Rockett, a U. of I. materials science and engineering professor.

Energy from photovoltaic modules or solar cells is a source of renewable power with high growth potential in parts of the United States, they said. Operational solar arrays exist in southern states, mostly in the Southwest where cloud cover is less frequent.

Automated weather stations, part of the ISWS Water and Atmospheric Resources Monitoring program, monitor weather and climate variables throughout Illinois. Each station includes a device called a pyranometer that measures solar energy.

“Sensors have been in place for more than 14 years and automatically report hourly data year round,” Scott said. “That’s long enough to provide a good indication of monthly and seasonal solar energy potential across Illinois.”

Using information from a solar power array in Arizona as a template for power output, Rockett and Scott examined current solar cell efficiencies and retail prices, and then applied solar data for Illinois to estimate power output potential for small to medium solar arrays in Illinois – averaging about 180 kilowatt hours per square meter of solar array per year in Central Illinois.

Because of the capital costs of generating the energy used by typical homeowners and the typical solar radiation that occurs in Illinois, solar power isn’t cost-efficient now in Illinois. “Photovoltaics are cost-effective for small remote applications, such as powering billboards, but not for homes or businesses, at least not without incentives,” Rockett said.

Considering the size of the array needed, additional equipment required, and interest on a 20-year loan to fund the warranted life of the equipment, Rockett estimates that costs could be as high as 50 cents per kilowatt hour, much higher than the 11 cents per kilowatt hour local utilities today charge homeowners for power.

Research indicates that solar power could be acceptable in other applications. Net metering – selling unused generated power back to a utility – would lower cost differences. In addition, extending commercial power to remote locations requires the additional cost of transmission lines. The cost of installing a half-mile of transmission lines equals the cost of a solar array capable of generating 625 kilowatt hours per month.

“Solar power generation is a viable option at today’s current prices for those needs,” Rockett said.

The cost-effectiveness of photovoltaics will increase significantly if subsidies, tax incentives, and economy-of-scale discounts in both module and balance-of-system costs are available to reduce initial system price. Such incentives are available now for wind-turbine installations in Illinois.

Last year, Gov. Rod Blagojevich proposed a Sustainable Energy Plan that would require Illinois electric utilities to provide 8 percent of their electricity from renewable sources by 2013 and boost investment in energy-saving programs. The proposal has accelerated the development of wind farms and prompted the Illinois Commerce Commission to consider renewable energy requirements and expansion of programs to reduce energy use.

Blagojevich recently announced a comprehensive long-term energy plan that would replace Illinois’ dependence on foreign oil with homegrown alternatives.

The solar energy report is available online in pdf form.