Optimizing Energy Provision on small Islands including a Desalinated Water Constraint applied to Cape Verde

Abstract

thesis proposes a new approach for energy provision applicable to all small islands including desalinated water constraints. It includes the generation of energy through renewable energies and/or synfuel; electrolyzer, fuel cell, and desalination plants as conversion technologies as well as storage in batteries, synfuel tanks, and/or hydrogen tanks. With the objective of determining the most cost-effective configuration to deliver energy in small islands, the developed approach considers several transmission alternatives: (i) subsea direct current power cables, (ii) specific vessels delivering either synfuels or hydrogen, (iii) hydrogen pipelines and (iv) cargo, containers and/or fuel trucks carrying energy carriers loaded into existing Roll on – Roll off ships or ferries routes. Three scenarios were considered: (i) a baseline scenario that represents existing energy systems on islands, (ii) a Mixed-Use scenario that only includes existing ferry routes for synfuel delivery, and (iii) 100% RE where the 2050 demand is met sustainably. Moreover, a new criterion for seawater reverse osmosis desalination site selection was also developed thus limiting any green hydrogen production to the maximum eligible land. By using Cape Verde to validate the model, results show that land eligibility ranges from 0 to 42% and that slope, wetlands, and isolated settlements are crucial criteria. Also, the most cost-effective scenario is the Baseline which requires an investment of 246 million euros. Due to several reasons, the Mixed-Use scenario increases the investment by a factor of 4 while the 100% RE scenario overcomes the 5 billion euros mark. Among the RE sources, there’s a clear dominance of onshore wind over PV being the most deployed source in all scenarios.