Energy analysis and environmental impact assessment for self-sufficient non-interconnected islands: The case of Nisyros island

Abstract

The European continent is surrounded by islands, which even though geographically and socially diverse, share common energy burdens regarding heavy fossil fuels reliance. More specifically, the non-interconnected islands (NII) encounter unique challenges in the decarbonization processes, rendering them particularly vulnerable to the impacts of such transitions. Numerous studies have been conducted to address such emerging issues. However, a research gap exists, as most of the proposed RES-related grid interventions neglect actual historical data in favor of a more theoretical, but possibly misleading, approach. In addition, potential grid stability concerns arising from high levels of RES penetration remain unaddressed. To this end, the objective of the present study focuses on addressing mainly electrical grid stability and resiliency considerations (e.g. imbalances, frequency fluctuations, voltage unbalance rate, for the case of energy islands, as in the case of the NII Greek island of Nisyros). Two sustainable scenarios including novel technologies (e.g. flywheel instead of conventional BESS, a hybrid transformer, vehicle-to-grid chargers) are examined from an energetic and environmental perspective, for short- (2030) and mid-term (2050) implementation horizons, reaching electrical and energy self-sufficiency targets up to 50% and 95%, respectively. For the energy analysis, capacity-investment optimization problems, power flow simulations and specialized transient simulations were conducted, while for the environmental impact assessment a novel in-house developed tool was utilized. As a result, the proposed interventions can result in significant fossil fuel cost savings of about 88%, reduced CO2 emissions up to 38% and overall remarkable financial and environmental benefits. In conclusion, this study demonstrates that a NII can realistically abolish thermal energy to a bare minimum and enhance its self-sufficiency by harnessing local renewable energy potential, while at the same time ensuring grid stability.