Solar energy has the potential to contribute significantly to our increasing energy needs, if lawmakers provide support for research and tax incentives, according to speakers at a July 11 briefing on Capitol Hill hosted by the Optical Society of America and the Environmental and Energy Study Institute, in conjunction with the US House Renewable Energy and Energy Efficiency Caucus.

“This topic is extremely timely,” said Carol Werner of EESI, introducing the briefing. “Energy is dominating headlines.”

Sunlight is clean and abundant, but currently solar power contributes only one-eighth of 1% of electricity in the US. Doug Hall, director of photovoltaic glass technologies for Corning, described existing photovoltaic technologies and those in development. Existing photovoltaics, including wafered silicon (which has most of the market share now), and newer thin film photovoltaics (currently 5% of the market but expected to grow) are currently used for rooftops and small scale applications. More research is needed to improve the efficiency and bring down the cost of these technologies. In addition to technologies already on the market, a new generation of photovoltaics, using new classes of materials, is still in development.

Research and development are not anywhere near over; the technological challenges are many and interdisciplinary, Hall said. Growth of solar is just beginning to take off now, said Hall. The current market for photovoltiacs is about 4 GW; he predicted it would grow to 15-30 GW by 2020. Government legislation is needed to clear the way for growth, Hall said.

Chuck Kutscher of the National Renewable Energy Laboratory described another technology to use the sun’s energy: Concentrating Solar Power (CSP). There are several types of concentrators, each with advantages and disadvantages, but all of them basically work by using lenses or mirrors to concentrate sunlight in order to heat water in a steam generator to generate electricity. Large farms of concentrating solar power can be used for electric generating systems, and the cost of CSP is becoming comparable with the cost of natural gas, he said.

“We know this technology works; we have a lot of experience with it,” he said. Power companies have recently shown renewed interest in the technology. There are 4000 MW of concentrating solar power projects planned in the US, and over 7000 MW are planned worldwide, he said. However, an investment tax credit for these is scheduled to expire, making companies uncertain about making further investments in the technology, said Kutscher.

In the 1970s there was a jump in funding for solar energy R&D, but funding then declined and leveled off, Fred Sissine of the Congressional Research Service pointed out. Historically solar energy has been given much less funding than nuclear and fossil fuel technologies.

Rhone Resch, President of the Solar Energy Industries Association, called solar “the next great high tech growth industry.” There is incredible demand for solar power, he said. Germany and Spain have led the market recently. Germany has actively put in place policies to encourage the use of solar power. Although Germany gets the same average sunlight as Anchorage, Alaska, it accounts for 46 percent of global photovoltaic demand. The United States, which gets much more sunlight, accounts for only 8 percent of the global photovoltaic market. In the US, tax credits for solar power are about to expire, and it is uncertain whether they will be renewed. Market demand for solar power is strong, said Resch, but such policy uncertainty can affect investor willingness to invest in large scale installations.

“We want a level playing field” with other technologies, Resch said. In order to expand the US solar market, Resch said we need a long term commitment to R&D, long term state incentives, long-term meaningful federal incentives, and public education.

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