신재생에너지 관련 보조금 축소에 대한 국제투자분쟁 사례 연구 ― Charanne v. Spain 및 Eiser v. Spain사건을 중심으로 ―

This study analyzes arbitral awards concerning the reduction of renewable energy subsidies and draws implications for Korea. As seen in the recent debate over the amendment or repeal of the U.S. Inflation Reduction Act (IRA), subsidies introduced to achieve strategic policy objectives may, when curtailed for fiscal or policy reasons, give rise to international investment disputes. Spain, after introducing various support measures such as the feed-in tariff (FIT) in the 2000s, drastically reduced and restructured its schemes following the 2008 financial crisis, leading to substantial investor losses and more than 50 ISDS claims. In Charanne v. Spain, the tribunal denied indirect expropriation and violation of fair and equitable treatment (FET), emphasizing that the economic use of the investment remained possible and that a reasonable investor should have anticipated regulatory changes. By contrast, in Eiser v. Spain, the tribunal recognized an FET violation, holding that the explicit guarantees of stability under RD 661/2007 had been undermined when subsequent regulatory changes caused the investment’s value to fall from €124 million to €4 million. These contrasting outcomes demonstrate that the boundary between legitimate expectations and the host state’s regulatory power depends heavily on the specific facts of each case. Based on this analysis, the paper highlights the need for Korean companies to strengthen ex ante risk management in overseas investment, and for the Korean government to ensure predictability and proportionality in subsidy design. It further underscores the importance of Korea’s strategic response to ongoing debates on the modernization of the Energy Charter Treaty (ECT) and ISDS reform.