Refineries are some of the biggest consumers of hydrogen today. Hydrogen is mainly being utilized for desulphurization of crude oil. Going forward refineries are expected to use more hydrogen due to stricter fuel quality regulations and lower crude oil quality. Electrolysis can play a key role, both to supply the increased demand for hydrogen for refineries, but also to lower the CO2 emissions, both from the refinery and the fuel itself. Refineries also consume oxygen, which can be supplied for on-site electrolysis.