Liquid hydrogen filling station. Test car (BMW 735i) being filled with liquid hydrogen fuel at a solar- powered hydrogen filling station. At left is the filling station; at right foreground is an array of photovoltaic solar cells. This is part of Solar- Wasserstoff-Bayern's solar hydrogen demonstration plant at Neunburg vorm Wald in Germany. The converted car can run for 300km's on a full tank of liquid hydrogen. Liquid hydrogen is obtained from water. The water is split into hydrogen (H2) and oxygen (O2) by electrolysis, using power obtained from the solar cells. This environmentally friendly fuel requires further development to make it as cheap as other fuels.