Gravitational Energy Storage With Weights

This chapter presents an overview of design decisions and trade-offs associated with selecting and sizing gravitational energy storage systems with weights. Pumped hydropower is an established grid-scale gravitational energy storage technology, but requires significant land-use due to its low energy density, and is only feasible for a limited number of locations due to the requirement for an upper and lower reservoir. In recent years, a range of new concepts have been proposed which aim to improve the energy density and scalability of gravitational storage through the use of solid material rather than water. The chapter first presents an overview of the major design decisions that separate specific systems from one another, and how these impact the viability for different energy storage applications. Then, a methodology is presented for calculating the levelized cost of storage considering the physical dimensions and energy storage application. Using this methodology, case studies are completed for an example single-weight underground gravitational energy storage system. It is shown that the economics depend on the physical scale at which individual systems are constructed, and that the energy storage application strongly influences which economic and technical parameters are most important for cost estimation.