자원·환경경제연구 ISSN:1229-9146(Print) Environmental and Resource Economics Review

This study examines the price effects of a pilot electricity market reform implemented in Jeju, Korea. The reform introduced a real-time market and a reserve market, and allowed renewable generators to submit price bids, thereby enabling renewable resources to set the system marginal price (SMP) directly. Using hourly day-ahead prices in Jeju from June 2023 to May 2026, we estimate the effect of the reform while controlling for fuel costs, electricity demand, and renewable generation potential. Fixed effects and year-over-year first-differenced models are estimated in parallel, as the two rely on different identifying assumptions. The results indicate that the SMP declined by approximately 9 KRW/kWh following the reform, with the two models yielding closely aligned estimates. The effect varies substantially across seasons and hours of the day, concentrating in spring and autumn and in the evening hours. These findings suggest that the price effects of renewable expansion depend not only on the volume of renewable generation but also on the institutional arrangements through which it enters the market.