Hydrogen is the most abundant gas in the universe and hydrogen-powered cars only emit water vapour. In principle therefore, hydrogen could be cheaper and cleaner than petrol as fuel for our cars. But hydrogen remains too dangerous in its liquid form to take on board enough fuel for a long journey.And so the race is on to find a way to store hydrogen in battery form. Research scientists at Swiss Norweigan Beam Line at the European Synchro-tron Radiation Facility in Grenoble are working on the problem. When a compound is found which can store hydrogen under ambiant conditions, it will be possible to build cheap, safe and easy-to-use hydrogen-powered cars.