Gotland, Sweden’s largest island located in the Baltic Sea, has been designated by the Swedish Energy Agency as a pilot region for renewable energy technology deployments and aims to achieve a climate-neutral energy system by 2025. By 2017, local wind power already supplied half of the island’s energy demand, with the remainder imported via submarine cables from the mainland (Nilsson, Gotland). With one of the highest wind potentials in Sweden, Gotland had around 180 MW of installed wind capacity producing 522 GWh annually as of 2020 (Ossa, 2021), and several upcoming onshore and offshore wind projects further strengthen its position as a prime location for an Adiabatic Compressed Air Energy Storage (A-CAES) plant. The island’s subsurface geology, dominated by salt and limestone formations, provides structurally stable caverns and underground reservoirs with low leakage potential, making them suitable for compressed air storage (Sopher, 2019), and ongoing research initiatives and pilot projects continue to assess the technical and economic feasibility of CAES development on Gotland. 

The primary objective of this study is to conduct a techno-economic assessment of wind farms integrated with A-CAES systems, focusing on both technical feasibility and the economic viability of the storage system. Specifically, the analysis aims to evaluate net present value (NPV) and revenue streams as well as determine the optimal system sizing. To achieve these objectives, the study is guided by two research questions: (1) What is the maximum revenue and NPV that can be achieved if A-CAES is integrated with the existing wind power plants in Gotland? and (2) What is the optimal size combination if new A-CAES and wind power plants are developed on the island?