Chemists describe solar energy progress and challenges, including the 'artificial leaf'

WASHINGTON, Nov. 5, 2009 — Scientists are making progress toward development of an "artificial leaf" that mimics a real leaf's chemical magic with photosynthesis — but instead converts sunlight and water into a liquid fuel such as methanol for cars and trucks. That is among the conclusions in a newly-available report from top authorities on solar energy who met at the 1st Annual Chemical Sciences and Society Symposium. The gathering launched a new effort to initiate international cooperation and innovative thinking on the global energy challenge.

The three-day symposium, which took place in Germany this past summer, included 30 chemists from China, Germany, Japan, the United Kingdom and the United States. It was organized through a joint effort of the science and technology funding agencies and chemical societies of each country, including the U. S. National Science Foundation and the American Chemical Society (ACS), the world's largest scientific society. The symposium series was initiated though the ACS Committee on International Activities in order to offer a unique forum whereby global challenges could be tackled in an open, discussion-based setting, fostering innovative solutions to some of the world's most daunting challenges.

A "white paper" entitled "Powering the World with Sunlight," describes highlights of the symposium and is available along with related materials here.

"The sun provides more energy to the Earth in an hour than the world consumes in a year," the report states. "Compare that single hour to the one million years required for the Earth to accumulate the same amount of energy in the form of fossil fuels. Fossil fuels are not a sustainable resource, and we must break our dependence on them. Solar power is among the most promising alternatives."

The symposium focused on four main topics:

• Mimicking photosynthesis using synthetic materials such as the "artificial leaf"
• Production and use of biofuels as a form of stored solar energy
• Developing innovative, more efficient solar cells
• Storage and distribution of solar energy

The scientists pointed out during the meeting that plants use solar energy when they capture and convert sunlight into chemical fuel through photosynthesis. The process involves the conversion of water and carbon dioxide into sugars as well as oxygen and hydrogen. Scientists have been successful in mimicking this fuel-making process, termed artificial photosynthesis, but now must finds ways of doing so in ways that can be used commercially. Participants described progress toward this goal and the scientific challenges that must be met before solar can be a viable alternative to fossil fuels.