The Energy Tax Act constitutes a programme of tax credits for households and businesses purchasing alternative energy equipment. Residential energy (income) tax credits for solar and wind energy equipment expenditures were set at 30% of the first USD 2000 invested and 20% of the next USD 8000. The most important electricity sector incentive was the creation of a 10% business energy tax credit for investments in various renewable energy options including solar, wind, and geothermal. This credit was in addition to the standard 10% investment tax credit, which was available on all types of equipment. The residential and business credits were extended and improved in 1980. Public utility property was specifically excluded from eligibility for the tax credits that were to expire at the end of 1982. The bill also created an excise tax exemption of USD 0.04 per gallon of blended gasoline for alcohol fuels (ethanol and methanol), which was equivalent to the full value of the excise tax at that time. The ethanol excise tax exemption was extended in 1980. The credit was set to expire in 1984 but has been extended several times since at different levels of exemptions.