Commitment vs. Discretion in Climate and Energy Policy

To decarbonize the power sector policy-makers need to commit to long-term credible rules for climate and energy policy. Otherwise, time-inconsistent policy-making will impair investments into low-carbon technologies. However, the future benefits and costs of decarbonization are subject to substantial uncertainties. Thus, there may also be societal gains from allowing policy-makers the discretion to adjust the policies as new information becomes available. We examine how this trade-off between policy commitment and discretion affects the optimal intertemporal design of policies to support the deployment of renewable energy sources. Using a dynamic partial equilibrium model of the power sector, we show that commitment to state-contingent renewable subsidies outperforms both unconditional commitment and discretion. The choice between the practically more feasible approaches of unconditional commitment and discretion is analytically ambiguous. A numerical illustration with naïve assumptions suggests that policy discretion may outperform unconditional commitment in terms of welfare. However, extensions to more realistic cases where only a limited fraction of climate uncertainty resolves, where future policy-makers have own agendas, or with risk-averse investors show commitment as favorable.