Dear EarthTalk: I’m “pro-solar” all the way for the sake of the environment, but solar power has not historically been very cost-effective. What innovations are coming down the pike that will bring costs down to make solar competitive with other energy sources? -- Will Proctor, Richmond, VA

   The prospect of generating pollution-free power from the sun’s rays is appealing, but to-date the low price of oil combined with the high costs of developing new technology have prevented the widespread adoption of solar power in the United States and beyond. At a current cost of 25 to 50 cents per kilowatt-hour, solar power costs as much as five times more than conventional fossil fuel-based electricity. And dwindling supplies of polysilicon, the element found in traditional photovoltaic cells, are not helping.

    The Politics of Solar Power
   According to Gary Gerber of the Berkeley, California-based Sun Light & Power, not long after Ronald Reagan moved into the White House in 1980 and removed the solar collectors from the roof that Jimmy Carter had installed, tax credits for solar development disappeared and the industry plunged “over a cliff.”

   Federal spending on solar energy picked up under the Clinton administration, but trailed off again once George W. Bush took office. But growing climate change worries and high oil prices have forced the Bush administration to reconsider its stance on alternatives like solar, and the White House has proposed $148 million for solar energy development in 2007, up almost 80 percent from what it invested in 2006.

    Increasing the Efficiency and Lowering the Cost of Solar Power
   In the realm of research and development, enterprising engineers are working hard to get solar power’s costs down, and expect it to be price-competitive with fossil fuels within 20 years. One technological innovator is California-based Nanosolar, which replaces the silicon used to absorb sunlight and convert it into electricity with a thin film of copper, indium, gallium and selenium (CIGS).

   Nanosolar Martin Roscheisen says CIGS-based cells are flexible and more durable, making them easier to install in a wide range of applications. Roscheisen expects he will be able to build a 400-megawatt electricity plant for about a tenth of the price of a comparable silicon-based plant. Other companies making waves with CIGS-based solar cells include New York’s DayStar Technologies and California’s Miasole.

   Another recent innovation in solar power is the co-called “spray-on” cell, such as those made by Massachusetts’ Konarka. Like paint, the composite can be sprayed on to other materials, where it can harness the sun’s infrared rays to power cell phones and other portable or wireless devices. Some analysts think spray-on cells could become five times more efficient than the current photovoltaic standard.