Hydrogen

The supply of hydrogen for industrial use is a major global business, with demand rising threefold since 1975 – and continuing to grow. Hydrogen production however is currently supplied almost entirely supplied from fossil fuels, consuming around 6% of global natural gas and 2% of global coal supplies. With global CO2 emissions from hydrogen production currently estimated at 830 million tonnes annually - equivalent to the combined emissions of the United Kingdom and Indonesia – this rise in production is not compatible with growing efforts to limit global temperature rises. 

Three main types of electrolyser exist, alkaline, proton exchange membrane, (PEM), and solid oxide, categorised by the type of electrolyser used. Alkaline electrolysers, the most common, use an alkaline solution, and are known for their durability and low-cost operation, although are less efficient than the other types. PEM electrolysers, which use a solid polymer electrolyte, offer high efficiency, fast response times, and compact design, but are more expensive than their alkaline counterparts, since they use precious metals, such as platinum, in their catalysts.Solid oxide electrolysers use a solid ceramic material as the electrolyte, can achieve very high efficiencies but require high operating temperatures and have slower  response times then PEM electrolysers.

Currently responsible for only around 2% of global hydrogen production, water electrolysis generates green hydrogen, by harnessing wind and solar power as inputs to the process.