Hydrogen is regarded as an excellent candidate future fuel on the grounds that it is relatively easy to store and it burns cleanly to produce only heat and water. But present methods of production involve fossil fuels and are energy intensive, offsetting any benefits of the hydrogen. Instead, scientists would like to use electricity from renewable sources to split water into hydrogen and oxygen, with solar power being one obvious choice. Unfortunately, current silicon-based cells cannot produce a sufficiently high output voltage individually, meaning that several of them need to be linked... Like this podcast? Please help us by supporting the Naked Scientists