Scientists are developing a technique which mimics photosynthesis in order to generate clean, cheap energy.
Researchers at the Massachusetts Institute of Technology in the US have reproduced the technique, which uses solar power to split water molecules, in genetically modified viruses.
It is hoped that if executed on a larger scale, the process could lead to an endless supply of environmentally-friendly hydrogen fuel, which can be used to generate domestic and business energy and run vehicles.
Professor Thomas Mallouk of Pennsylvania State University said: "This is an extremely clever piece of work.
"But to be cost-competitive with other approaches to solar power, the system would need to be at least ten times more efficient than natural photosynthesis, be able to repeat the reaction a billion times and use less expensive materials."
Lead researcher Angela Belcher, Germeshausen professor of materials science and engineering, said a prototype that will be able to carry out the whole process of splitting water molecules into oxygen and hydrogen will be available within two years.
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