DOE Report Highlights Promising Areas of Solar Energy Research

By Ernie Tretkoff

Sunlight has great potential to supply the world with abundant clean energy, but more research needs to be done to make solar power competitive with fossil fuels, according to a recent Department of Energy (DOE) report. The report, Basic Research Needs for Solar Energy Utilization, lists promising priority research directions for solar energy.

The report is the result of a workshop held in April by the DOE Office of Basic Energy Sciences. Over 200 scientists representing academia, national laboratories, and industry in the United States and abroad attended the workshop. The report is similar in scope to a report released two years ago on research needed for the hydrogen economy.

Sunlight is by far the largest carbon-neutral energy source, the report notes. More energy reaches Earth from the sun in an hour than is used on the planet in an entire year. Yet solar electricity currently provides only approximately one millionth of the total electricity supply. World demand for energy is expected to more than double by 2050. “Finding sufficient supplies of clean energy for the future is one of society’s most daunting challenges,” the report states.

To meet this challenge, more research is needed. “We spend more money in ten minutes buying gas at the pump than we spend on solar energy R&D in a year,” said Nathan Lewis, a chemist at Caltech who was one of the workshop chairs.

The workshop attendees identified 13 priority research directions that could advance solar energy conversion to electricity, fuels, and thermal end uses. Many of the suggested research directions build on recent advances in nanotechnology and biotechnology. Better ways of exploiting a larger part of the solar energy spectrum, making cheap materials function as well as expensive ones, and developing new materials that absorb sunlight more efficiently are among the research goals.

According to the report, the proposed research could also lead to a number of advances, including artificial "molecular machines" that turn sunlight into chemical fuel, "smart materials" based on nature's ability to transfer captured solar energy with no energy loss, cheap plastic solar cells, new photovoltaic designs, solar concentrators, new materials for thermal storage, and ways to use sunlight to split water molecules into oxygen and hydrogen that can be used for fuel.

These are all promising research directions, said Lewis. He says he is optimistic that efficient ways to use solar energy can be developed because the basic principles of solar energy conversion are understood. “We’re good at applying fundamental principles to develop technologies that help change our lives. Once we have the principles, we can figure out how to do it. There are no laws of physics that we don’t know here.”

“This report demonstrates the important contribution the entire scientific community can make to the development of new sustainable energy resources,” Ray Orbach, Director of DOE’s Office of Science, said in a press release. “Science and basic research can and must play a key role in addressing the energy security needs of our nation.”

It has not yet been determined how much funding will be available for solar energy research. “This is a really important problem. The question is whether the country is serious about doing something. We all are going to hang on to see if the country is serious about exploiting this renewable resource,” said Lewis.

The full report is available at http://www.sc.doe.gov/bes/reports/abstracts.html#SEU