 Energy taxation has been used as a policy instrument ever since the oil crisis of the 1970s to support renewable energy and nuclear power.Energy tax was reduced by half in 1991 during the tax reform, simultaneously with the introduction of a tax on fossil fuels, with exceptions on ethanol, methanol, other biofuels, peat and wastes.As one part of the Government's long-term energy policy to reduce GHG emissions, the Swedish government introduced a voluntary international system for trading "green certificates", i.e.