Heterogeneity in State Solar and Wind Deployments : Trade-Offs between Technology-Neutral and Technology-Specific Renewable Energy Policies

This study develops a theoretical framework that differentiates the shares of electricity generation between two types of renewables, solar and wind, and evaluates the impacts of technology-neutral and technology-specific renewable energy policies on state-level solar and wind deployments. Our empirical results based on the Zero-One-Inflated Beta regression model and state-level panel data from 2001 to 2019 suggest greater solar but lower wind deployment with the adoption of Renewable Portfolio Standard with Solar carve-outs (SRPS), a technology-specific policy. Specifically, we find that a one percentage point increase in SRPS boosts solar share by 0.77 percentage points but decreases wind share by 0.78 percentage points. In contrast, with a one percentage point increase in renewable portfolio standard without a solar carve-out (RPS), a technology-neutral policy, wind share increases by 0.76 percentage points and solar share decreases by 1.22 percentage points. We also examine the extra cost of SRPS, the role of credit trading, and heterogeneous impacts across operator scales and treatment timing