Decarbonizing Electricity Generation with Intermittent Sources of Energy

We examine policy instruments that aim to decarbonize electricity production by replacing fossil fuel energy with intermittent renewable sources, namely, wind and solar power. We consider a model of investment, production, and storage with two sources of energy: one is clean but intermittent (wind or solar), whereas the other one is reliable but polluting (thermal power). We first determine the first-best energy mix depending on the social cost of polluting emissions. We then show that, to implement the socially efficient energy mix without a carbon tax, feed-in tariffs and renewable portfolio standards must be complemented with a price cap and volume-limited capacity payments.