 However, according to an impact assessment by the European Commission, this is still below the best available technological (BAT) efficiency levels of 46–49%.With gas-fired power plants the average efficiency is 52% compared to 58–59% with best available technology (BAT), and gas and oil boiler plants operate at average 36% efficiency (BAT delivers 47%).According to that same impact assessment by the European Commission, raising the efficiency of all new plants and the majority of existing plants, through the setting of authorisation and permit conditions, to an average generation efficiency of 52% in 2020 would lead to a reduction in annual consumption of of natural gas and of coal.