The REMI Policy Insight Plus model was applied in an innovative manner to this study to analyze the impacts of major greenhouse gas mitigation options at the macroeconomic level in Pennsylvania for the policy horizon of 2009-2020. The corresponding results indicated that the net impacts on the State’s economy would be significantly positive and that greenhouse gas mitigation activities have a wide range of macroeconomic impacts, some of which were negative, but others provided significant cost savings through energy efficiency and thereby provided an economic stimulus to households and businesses, therefore making the expected gains exceed the expected losses. The analysis uncovered that, although many analysts focused on potential losses to energy sectors, there was strong potential for growth in construction and key manufacturing sectors.