Storing Sunlight Could Create Constant Solar Energy

Scientists may have hit the jackpot on creating a constant source of solar energy, solving a great energy riddle. To date, solar energy has not been seen as a totally viable energy source because the Sun is not always shining. In spite of this, researchers may have found a way to store solar energy, one of the major challenges in creating renewable solar fuels.

"Ultimately the renewable energy problem is really a storage problem," said Gary Moore chemist at Berkeley Lab's Physical Biosciences Division. "Given the intermittent availability of sunlight, we need a way of using the sun all night long." The study, published in Physical Chemistry Chemical Physics, showed that almost 90 percent of the electrons designed to store solar energy are found in a specific area of the target hydrogen molecule.

In addition, storing solar energy in the chemical bonds of a fuel provides the immense power that is imperative for modern transport systems.

Scientists hope that through their technological breakthrough in artificial photosynthesis, the chemical process that converts sunlight, water, and carbon dioxide into carbohydrates and oxygen, they can produce energy-dense fuels from nothing more than sunlight, water and atmosphere-warming carbon dioxide, ideally, with no byproducts other than oxygen. However, realizing this will require a number of innovative scientific breakthroughs including high performance electrical conductors that can increase the rate of fuel production from sunlight alone.

Last year, researchers took a step toward accomplishing this goal by creating gallium phosphide/cobaloxime hybrid. Gallium phosphide absorbs visible light which enables it to produce significantly higher photocurrents and an increased intensity of radiation. The cobaloxime catalyst is fairly inexpensive and easily accessible due to its abundance, making it a much more suitable choice over currently used expensive metals, such as platinum.

The analysis also confirmed that the light-absorber component of their photocathode, an electrical conductor, is a major limiter to obtaining higher electric current.

"This tells us that the use of light absorbers with improved spectral coverage of the sun is a good start to achieving further performance gains, but it is likely we will also have to develop faster and more efficient catalysts as well as new attachment chemistries," said Moore.

Efficiency, durability, and feasibility are all characteristics that are taken into account when choosing material for solar fuel technologies. The researchers' method creates an enhanced model for testing combinations of new sustainable solar-fuel materials.