Life-cycle emissions of nitric oxide and sulphurous oxides from various types of electric-power generation systems have been estimated. Emissions from the process of building energy systems, as well as from the mining and transportation of the fuel were accounted for as well as the emissions from power stations. Two types of thermoelectric systems, namely a LNG-fuelled gas-turbine combined cycle and an integrated coal-gasification combined cycle, and four types of renewable energy systems — photovoltaic, hydropower, wind power and ocean thermal energy conversion — were evaluated. The estimated amounts of nitric oxide emitted per generated unit of electricity range from 0.06 to 0.3 g/kWh, while the amounts of suphur oxides range from 0.3 to 0.53 g/kWh. There is a tendency for renewable-energy systems to emit lower amounts of nitric oxide.