Splitting hydrogen from water molecules via electrolysis requires energy, which ideally comes from renewable energy sources. Scientists at the Fraunhofer Institute for Solar Energy Systems ISE have developed a combined photovoltaic/electrolysis module that efficiently produces hydrogen directly from solar energy. To do this, the water molecule is split using the high photovoltage of multi-junction solar cells, which in turn are electrically and thermally connected to electrolyzer cells.
A demonstrator from the research team tested outdoors converted up to 31.3% of solar energy into chemical energy, based on the higher heating value of hydrogen.