Signed into law in October 2008, the Emergency Economic Stabilization Act of 2008 (H.R. 1424) included the Energy Improvement and Extension Act, which extended production tax credits (PTC) and investment tax credits (ITC) for various renewable energy sources, which were due to expire at the end of 2008. It also modified existing tax incentives for energy efficiency investments, as well as creating new ones. In terms of energy efficiency, the bill extended energy efficiency tax deductions for commercial buildings through 2013 and revived similar deductions for home improvements installed in 2009, adding a new USD 300 tax credit for energy-efficient biomass fuel stoves. It also extended tax credits for builders of new energy-efficient homes through 2009 and increased tax credits for manufacturers of energy-efficient appliances, while extending that credit through 2010. The act created a new tax credit of up to USD 7,500 for plug-in hybrid vehicles, expected to go on sale in 2010, while providing tax exemptions for idle reduction technologies and advanced insulation installed in trucks. Electric charging stations will now also be covered by a 30% tax credit through to 2010. To facilitate financing, the bill authorised USD 800 million in Qualified Energy Conservation Bonds, which will be issued by state and local governments. The bonds can be applied to a wide range of energy efficiency projects, research and demonstration projects, and even renewable energy projects. The bill also extended the authority to issue bonds for qualified green building and sustainable design projects through 2012. The Act also aims for a more complete use and benefit of the tax credits. To this end it includes a provision to increase the income limits for the Alternative Minimum Tax (part of the federal income tax system which limits the types of deductions certain taxpayers can use to lower their tax). It also allows unused tax credits to be carried over to the following year.