Market power in renewable portfolio standards

Renewable portfolio standard (RPS), which requires a certain percentage of electricity production from renewables, has received considerable attention. One emerging issue is the possibility of strategic behavior in the renewable energy certificate/credit (REC) market, and its spillover effects on the electricity market. This paper develops dominant firm-competitive fringe models that account for market power. We show that market power could have significant impacts on the REC and power prices. In particular, when a nonrenewable generator is a dominant firm and a renewable generator is a competitive fringe, the nonrenewable firm has a strong incentive to lower the REC price, even to zero for avoiding REC costs. The zero REC price would negate price impacts in the power market, thereby mitigating market power of the dominant firm. However, this could lead to an underinvestment in renewables in the long run as subsidies received by renewables in form of RECs vanish. Therefore, regulatory agencies need to carefully oversee the market performance to ensure a healthy development of renewable industries under the RPS policies.