Wind energy and natural gas-based energy storage to promote energy security and lower emissions in island regions

Usually, isolated and remote areas, like islands, meet their electricity needs using oil-fired power generators. When available, natural gas can potentially substitute oil. Moreover, the high-quality wind energy potential found in many of these areas cannot be used extensively. Main reason is the operation of small-scale, weak electricity grids which cannot cope with wind energy intermittency. To compensate for that, we examine the combination of wind energy and energy storage. For the latter we focus on the technology of compressed air energy storage (CAES), which is suitable for scalable applications. To ensure the highest level of demand satisfaction, while avoiding system oversizing, we recommend a novel Wind-CAES system that allows switch from the CAES to the Brayton cycle when the stored energy is inadequate to meet demand. We develop a new algorithm for the sizing of such configurations, and use it on a case study that includes a typical, medium-scale Aegean Sea island in combination with three representative wind regimes. The results demonstrate that even in areas with relatively low-quality wind potential there are significant improvements in fuel use reduction, CO2 emissions and strengthening of energy supply security, while for island regions with higher-quality wind potential, the proposed solution also becomes cost-effective in comparison to other alternatives.