Long-duration energy storage (LDES) technologies are expected to see meaningful cost reductions by 2030, driven by technological improvements, increased manufacturing scale, and supply chain maturation, according to a new study released by the LDES Council in collaboration with the Electric Power Research Institute (EPRI).

In this study, “cost reductions” are defined strictly in terms of changes in total plant cost (TPC), which is used as the primary capital expenditure metric.

Technology Groupings

The report assesses five LDES categories.

Intraday electrochemical storage includes sodium-sulfur, vanadium redox flow, and iron-salt batteries for 8 to 12-hour power-to-power applications, competing with lithium-ion systems at longer durations due to lower marginal energy costs.

Intraday pumped heat energy storage (PHES) converts electricity to thermal energy and back using hot and cold reservoirs and is assessed only for 2030 due to limited near-term readiness.

Multi-day storage includes technologies capable of more than 100 hours of discharge, such as e-fuels, reversible fuel cells, metal-air, and geomechanical systems, defined by use case rather than technology.

Thermal energy storage (TES) focuses on power-to-heat applications using sensible or phase-change materials for industrial and district heating, with thermal efficiencies of 95–97%.

Cost Trends and Outlook

Cost ranges are expected to tighten by 2030, indicating convergence as technologies mature, manufacturing scales up, and supply chains stabilize.

TES and intraday electrochemical storage show the widest cost spreads in 2025, reflecting early-stage heterogeneity, while intraday PHES and multi-day storage report only 2030 scenarios due to insufficient 2025 data.

Intraday electrochemical energy storage is projected to have the fastest cost decline, with an average TPC reduction of approximately 37% between 2025 and 2030. On a U.S. Lower 48 basis, the 2025 TPC range is wide, spanning from $220 to $572/kWh. By 2030, the TPC range will narrow to $244-$358/kWh.

Thermal energy storage is projected to reduce TPC by 16% to 47% by 2030, suggesting that many technologies remain early on the cost curve.

Intraday compressed gas energy storage shows more moderate projected reductions of 6% to 25% by 2030, reflecting relatively mature mechanical components combined with ongoing system optimization. The 2025 TPC range is estimated at $158 to $471/kWh, narrowing to $118 to $445/kWh in 2030 on a normalized U.S. basis.

Growth rates cannot be calculated for intraday PHES and multi-day energy storage because 2025 data are unavailable, although PHES exhibits relatively narrow cost ranges in 2030.

Investment Metrics, Risks, and Policy

The report emphasizes that capital expenditure is the primary benchmarking metric for LDES, rather than the levelized cost of storage. LDES value is framed around reliability, long-duration resilience, and capacity adequacy.

Multi-day systems achieve very low dollar-per-kilowatt-hour values primarily due to long discharge durations rather than low total capital costs. Operations and maintenance costs generally account for a small share of TPC, but uncertainty remains high due to limited commercial operating experience.

Key risks highlighted include medium cost certainty levels, changing technology mixes between 2025 and 2030 datasets, unclear future operations and maintenance cost structures, and differences in cost definitions and system boundaries across studies. Many technologies remain at technology readiness level (TRL) 6 or lower, leaving commercial deployment timelines uncertain.

In December 2024, the LDES Council reported that LDES must scale up 50 times faster than projected in its 2024 Annual Report. According to the report, LDES solutions of more than 1 TW and up to 8 TW are needed by 2030 and 2040, respectively, globally to achieve the net-zero emissions target.