Hydrogen Solar is a UK company set up in 1999 to commercialise a pioneering Swiss technology. Its core product, the Tandem Cell, looks like a conventional solar panel but uses sunlight to generate hydrogen fuel. Ultimately, it could help hydrogen supplant oil as a source of vehicle fuel by enabling businesses and homes to afford their own hydrogen generators. But first it must achieve much higher levels of efficiency.

The technology was invented by two Swiss academics. When one of them, Michael Graetzel, professor at the Swiss Federal Institute of Technology in Lausanne (EPFL) mentioned it during a lecture in London in 1998, its commercial potential was spotted immediately by Julian Keable, a British architect with an interest in energy- efficient building techniques.