Evaluating the Underwater Compressed Air Energy Storage Potential in the Gulf of Maine

The United States has recognized the need to offset current and future electrical demand with clean, renewable generation. However, plans for integration of high penetration levels of often variable and uncertain renewable energy, like offshore wind, pose significant challenges to utility gird operators and system planners. The intermittent nature of renewables can result in dramatic changes in system load, indicating a need for large-scale energy storage technologies that would allow renewables to be dispatched when needed. Among different storage technologies, pumped hydro storage, batteries and fuel cells have some inherent advantages over others but only compressed air energy storage (CAES) has the capacity of pumped hydro and potentially lowest overall capital and capacity costs. Advances in system compression designs and utilization of thermal energy storage has made CAES increasingly attractive, especially as new innovations in air storage technologies are now allowing CAES to break away from site specific geological formations like salt domes by allowing the air to be stored underwater in pressure vessels. In this paper, a thermodynamic evaluation of an idealized underwater pressure-balanced CAES system is conducted and compared to other large-scale underwater storage methods. Using the Gulf of Maine as a case study area, the thermodynamic relations are integrated in ArcGIS, a geospatial analysis program, to determine the energy storage resource potential for the New England area.