A number of energy tax provisions expired at the end of 2014. Expired provisions include those that support renewable electricity (the production tax credit (PTC)), provisions that support energy efficiency in both residential and commercial buildings, and tax credits for certain biofuels and other alternative fuels. Like the 113th Congress, the 114th Congress may choose to address expired energy tax provisions. The Tax Increase Prevention Act (P.L. 113-295), enacted late in the 113th Congress, temporarily extended, through 2014, most expired energy tax provisions. Energy tax policy may also be considered as part of comprehensive tax reform legislation in the 114th Congress. A base-broadening approach to tax reform might consider the elimination of various energy tax expenditures in conjunction with a reduction in overall tax rates. This was the approach taken in the Tax Reform Act of 2014 (H.R. 1), introduced late in the 113th Congress by then-Chairman of the House Ways and Means Committee, Dave Camp. Alternative revenue sources, such as a carbon tax, may also be evaluated as part of the tax reform process. The Obama Administration has also proposed a number of changes to energy tax policy as part of its annual budget proposal. In the past, the Administration has proposed repealing a number of existing tax incentives for fossil fuels, while providing new or expanded incentives for alternative and advanced technology vehicles, renewable electricity, energy efficiency, and advanced energy manufacturing. Energy tax policy involves the use of one of the government's main fiscal instruments, taxes (both as an incentive and as a disincentive) to alter the allocation or configuration of energy resources and their use. In theory, energy taxes and subsidies, like tax policy instruments in general, are intended either to correct a problem or distortion in the energy markets or to achieve some economic (efficiency, equity, or even macroeconomic) objective. The economic rationale for government intervention in energy markets is commonly based on the government's perceived ability to correct for market failures. Market failures, such as externalities, principal-agent problems, and informational asymmetries, result in an economically inefficient allocation of resources-in which society does not maximize well-being. To correct for these market failures governments can utilize several policy options, including taxes, subsidies, and regulation, in an effort to achieve policy goals. In practice, energy tax policy in the United States is made in a political setting, determined by fiscal dictates and the views and interests of the key players in this setting, including policy makers, special interest groups, and academic scholars. As a result, enacted tax policy embodies compromises between economic and political goals, which could either mitigate or compound existing distortions.