Techno-economic analysis of recuperated Joule-Brayton pumped thermal energy storage

This article describes a techno-economic model for pumped thermal energy storage systems based on recuperated Joule-Brayton cycles and two-tank liquid storage. Models have been developed each component, with particular emphasis the heat exchangers. Economic metrics such as power capital costs (i.e., per-kW per-kWh capacity) levelized cost of are evaluated by gathering numerous correlations from literature, thereby enabling estimates uncertainty. It is found that use exchangers effectivenesses up to 0.95 economically worthwhile, but higher values lead rapidly escalating component size system cost. Several hot fluids considered; those operating at highest temperatures (chloride salts) improve round-trip efficiency benefit marginal may not warrant additional material risk when compared lower-temperature nitrate salts. Cost-efficiency trade-offs explored using multi-objective optimization algorithm, yielding optimal designs efficiencies in range 59–72% corresponding 0.12 ± 0.03 0.38 0.10 $/kWhe. Lifetime competitive lithium-ion batteries discharging durations greater than 6 h under current scenarios.