We take a first look at limitations on the use of energy-related tax credits contained in the General Business Credit (GBC) due to limitations within the regular corporate income tax as well as the AMT. Between 2000 and 2005, firms were unable to use all energy-related tax credits due to GBC limitations in the regular tax. The AMT has a smaller but still pronounced impact on the ability of firms to use these credits. Finally we provide some illustrative calculations to demonstrate how the AMT can lead to very different levelized costs of producing electricity from a wind power project.