실물옵션을 이용한 PPA 최적 투자 시점 분석 Ⅱ: 이중불확실성하에서의 탄력적 PPA 계약 방식을 중심으로

This study focuses on the sluggish expansion of the PPA(Power Purchase Agreement) market, despite expectations that future electricity prices will exceed the contracted PPA electricity charge. As an alternative, instead of a rigid long-term PPA contract period (20 years), two flexible approaches to setting the PPA contract period are proposed. And, using the real option approach, this study analyzes whether PPA investment remains economically viable for the electricity user under double uncertainty in both electricity and emission credit prices, even when paying a premium on the contracted PPA electricity charge. The analysis shows that under the “contract period reduction and risk premium payment” structure, the optimal investment threshold is higher than that of a 20-year PPA, yet still more favorable than direct electricity procurement from KEPCO. Similarly, the “contract bifurcation and option premium payment” structure also yields a higher optimal investment threshold than the 20-year PPA, but remains more advantageous than direct electricity procurement from KEPCO. In conclusion, in a continuously rising electricity price condition, it is economically rational for electricity users to shorten the PPA contract period while paying a risk premium or option premium to the renewable energy supplier.