Refineries and petrochemical plants are some of the biggest consumers of hydrogen today. Hydrogen is mainly being utilized for desulphurization of crude oil. Going forward these facilities 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 and petrochemical plants, but also to lower the CO2 emissions, both from the facility and the fuel itself. Refineries and petrochemical plants also consume oxygen, which can be supplied by on-site electrolysis.