Regulatory design and incentives for renewable energy

Increasing electric power production from renewable energy sources is currently one of the major objectives of energy policy. The intermittent nature of renewables, such as wind and solar, necessarily imposes complex trade-offs for regulatory objectives, such as resource adequacy (and system reliability) versus reductions in green house gas emissions. We develop a highly stylized model of investments in order to derive insights regarding the workings of regulatory incentives for increased renewable energy. We first show that incentives are indeed needed when there are significant economies of scale in the form of "learning by doing" or alternatively, when there is excess capacity in conventional technology due to legacy investments. We analyze two different regulatory schemes (feed-in tariffs and renewable portafolio standards) aimed at increasing investment in renewable capacity. We show that neither scheme is capable of inducing the socially optimal level of investment in renewable capacity. A single feed-in tariff fails to induce optimal investment as a feed-in tariff exceeding marginal costs of conventional technology incentivizes over-development of the most attractive sites which preempts investment in less attractive, yet socially valuable sites. A renewable portfolio standard that promotes increased investment in renewable technology induces under-investment in the conventional technology. These results suggest that a "clinical" regulatory design, that is, one that promotes the right amount of renewable capacity without affecting conventional capacity is a challenging proposition.