This dataset represents electricity generation from offshore wind farms in a specific region, including operation and maintenance processes such as turbine maintenance oil consumption and equipment replacement. The offshore wind power technology is characterized by wind turbines of average scale, with technical details consistent with those described in the corresponding wind turbine production dataset. The lifetime of wind farms is set according to official regulatory standards, with the technical service life of 20 years for onshore wind farms and 25 years for offshore wind farms. The data are primarily derived from official statistics and publicly available literature.