Aldy, Joseph2024-11-042024-11Aldy, Joseph. "How Big is the “Biggest Climate Spending Bill Ever?” Key Factors Influencing the Inflation Reduction Act’s Clean Energy Impacts." RWP24-007, November 2024.https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37379695The Inflation Reduction Act could deliver more than $1 trillion in tax expenditures and outlays targeting clean energy deployment, but considerable uncertainty characterizes the economic, emissions, energy, and fiscal implications of the law. I review the features of the political system governing implementation, the regulatory system overlaying performance standards, the innovation responding to IRA incentives, and the energy networks in which IRA-supported investments operate to identify the key factors influencing IRA’s outcomes. Drawing from past research and policy experience, I illustrate how these factors could play out and how future program evaluation could reduce uncertainty and inform better climate policy.en-USResearch Paper or Report2024-11-0410.3386/w33092