ITM Power, which specialises in energy storage and clean fuel, rocketed higher following the announcement of successful testing of a new membrane material for fuel cells.The firm claims the fuel cells' "power density ... has been increased by one order of magnitude". According to the firm "increasing power density is widely accepted as the single most important factor in reducing the cost of fuel cells," so the recent tests were aimed ultimately at reducing costs in manufacturing fuel cells, with the hope being that use of fuel cells will become commercially viable as one of the main power sources for cars as fossil fuel supplies are depleted.The chief executive of ITM, Graham Cooley said of the results: "The enthusiasm that has been shown by the automotive industry and fuel cell supply chain for the ... developments has been very encouraging. We now move to ... partner evaluation as a first step to commercialisation." BS