"Now we can start thinking about a totally distributed solar [photovoltaic] system," he said. "We couldn't have a solar economy unless it could produce energy 24/7. Now we can."
Daniel Nocera and Matthew Kanan at the Massachusetts Institute of Technology in Cambridge have discovered a simple, inexpensive system that can help to split water to produce oxygen and hydrogen gas. The process could, they suggest, be powered by solar photovoltaic cells.
This would give a crucial boost to solar power’s potential to replace fossil fuels, because it adds the ability to both trap and then store the Sun’s energy in a readily accessible form.
Storing solar-derived electricity still largely relies on bulky, inefficient batteries. Advocates of the 'hydrogen economy' propose that the gas is an ideal chemical storehouse for solar power, because it can be piped over long distances and potentially stored in compressed form, or adsorbed onto porous, portable materials.
This is similar to nature’s method of accumulating solar power – make chemical bonds to store the energy, and then break them to release that energy whenever it is needed. Plants ultimately use sugar molecules as their chemical-energy storehouses, but they start the process by rearranging water to get oxygen, protons and electrons. They do this using a huge protein molecule called photosystem II, which has at its heart the oxygen-evolving complex (OEC) — a cluster of manganese, oxygen and calcium atoms.
MIT solar colector
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