A Novel Analysis of Energy Density Considerations and Its Impacts on the Cost of Electrical Energy Storage (EES) Plants

Abstract

Geological restrictions and the low energy density of compressed air energy storage (CAES) plants constitute a technical and economic barrier to the enablement of variable and intermittent sustainable sources of energy production. Liquid air energy storage (LAES) and pumped thermal energy storage (PTES) systems offer a promising pathway for increasing the share of renewable energy in the supply mix. PTES remains under development while LAES suffers from low liquefaction unit efficiency, although it is at a higher technology readiness level (TRL) than PTES. The most significant element of large-scale EES is related to the discharge features of the power plants, especially the energy storage unit. Here, a novel multi-aspect equation, based on established codes and thermodynamic principles, is developed to quantify the required storage capacity to meet demand consistent with the design parameters and operational limitations of the system. An important conclusion of the application of the multi-aspect equation shows that liquid air storage systems instead of compressed air would reduce the space required for storage by 35 times. Finally, a cost equation was introduced as a function of the required storage volume. Calculations have demonstrated that the use of the novel cost equation, in lieu of the old one-aspect cost equation, for an LAES power plant with a production capacity of about 50 MW makes the costs of installing liquid air storage tanks against the total expenditure of the power plant about six times higher than what was reported in earlier research.

Compressed Air Energy Storage as a Battery Energy Storage System for Various Application Domains: A Review

“…In its liquid state, the air pressure is almost 700 times its ambient pressure value. This contributes immensely to the increase in energy density to 296.6 KJ/L compared to 70.07 KJ/L for CAES at 200 Bar, according to [158,159]. Table 4 captures the major parameter comparisons of the three different types of CAES vessels.…”

Untapping Industrial Flexibility via Waste Heat-Driven Pumped Thermal Energy Storage Systems

“…Energies 2023, 16, 6249 2 of 24 According to all these aspects, the development of large-scale long-duration (>8 h) energy storage (LDES) technologies will play a crucial role in clean energy future [2] to target weekly/seasonal energy storage and the shifting of RES production as well as to provide the flexibility needed on the grid. For all above mentioned purposes, powerto-heat-to-power solutions based on turbomachinery and thermal energy storages (also known as Carnot batteries [3]) can be a promising long-duration energy storage (LDES) technology offering large energy and power storage capacity, large storage cyclability, rapid response time, no dependency on geographical location (as pumped hydro storage), and durations from 6-12 h up to several weeks providing the flexibility needed for generators and transmission operators [4].…”