The Price Elasticity of Supply of Renewable Electricity Generation: Evidence from State Renewable Portfolio Standards
Johnson, Erik P.
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Many states have adopted policies aimed at promoting the growth of renewable electricity within their state. The most salient of these policies is a renewable portfolio standard (RPS) which mandates that retail electricity providers purchase a predetermined fraction of their electricity from renewable sources. Renewable portfolio standards are a policy tool likely to persist for many decades due to the long term goals of many state RPSs and the likely creation of a federal RPS alongside any comprehensive climate change bill. However, there is little empirical evidence about the costs of these RPS policies. I take an instrumental variables approach to estimate the long-run price elasticity of supply of renewable generation. To instrument for the price paid to renewable generators I use the phased-in implementation of RPSs over time. Using this IV strategy, my preferred estimate of the supply elasticity is 2.7. This parameter allows me to measure the costs of carbon abatement in the electricity sector and to compare those costs with the costs of a broader based policy. Using my parameter estimates, I find that a policy to reduce the CO₂ emissions in the northeastern US electricity sector by 2.5% using only an RPS would cost at least six times more than the regional cap-and-trade system (Regional Greenhouse Gas Initiative). The marginal cost of CO₂ abatement is $12 using the most optimistic assumptions for an RPS compared to a marginal cost of abatement of $2 in the Regional Greenhouse Gas Initiative.