Hydropower from Underground Pumped Storage

Abstract

Abstract This paper discusses the development of hydroelectric pumped storage in the United States and the growing need for peaking power. Energy storage in the form of water stored in a higher reservoir for later release to a lower reservoir to generate electric power is a practical and proved concept. In areas where stored energy is needed, but where no suitable sites are available for conventional pumped storage with both the upper and lower reservoirs above ground, underground pumped storage can be the answer. The feasibility of using underground caverns for the lower reservior in areas that have suitable rock formations is examined here. Included in this discussion are the size and type of underground configurations that are required and can be developed. The rock characteristics necessary are reviewed, as are the size and depth of the underground caverns that are required to store the water and to house the power plant. Equipment availability and its limitations are also considered. The studies are generally based on a 2000-MW underground pumped-storage project designed for a total head of 3200 ft and the reversible unit plant with two drops of 1600 ft each. Both anticipated costs of such facilities and the factors involved in the overall construction schedule are presented.