Material Insights · Understanding the Material World

Compressed-air and CO2 storage: Impact and additionality

Fuel-free storage at power-station scale to replace gas peakers

What this tab covers The impact and additionality lens: what it displaces on the grid, who gains and who bears the burden along the supply chain, and what happens at end of life.

Adiabatic CAES offers fuel-free storage of 5 to 8 hours or more at power-station scale, which can displace gas peakers; older diabatic plants are themselves gas users.

Grid decarbonisation versus fossil displacement

Favourable

At 5 to 10 hours and hundreds of megawatts, adiabatic and CO2 plants can cover evening peaks that gas turbines serve today. CAES was the largest long-duration storage technology installed in 2025, at 45 percent of more than 15 GWh of long-duration additions per Wood Mackenzie, and China holds 93 percent of cumulative long-duration installations. Developers claim about 490,000 t of CO2 avoided for Feicheng (stated alongside annual coal savings) and 411,000 t a year for Yingcheng; these are company claims with no published method or baseline. Diabatic plants reduce but do not remove gas burn.21316

CAES share of 2025 LDES installs 45% (Wood Mackenzie)16 China share of cumulative LDES 93%16 Claimed CO2 avoided about 490,000 t (Feicheng); 411,000 t/yr (Yingcheng) (developer claims)132

Just transition and local community impact

Favourable

Construction is civil and mechanical work similar to power-station building. Hydrostor expects about 700 peak construction jobs at Willow Rock and 40 permanent posts. Duke Energy and EPRI are studying Hydrostor's technology at a North Carolina coal site, a possible reuse of fossil plant land and grid connections. Deployment is concentrated in China, where Huaneng launched a two-unit, 700 MW second phase at the Jintan salt caverns in December 2024, storing up to 2.8 GWh. In India, NTPC is building a 160 MWh Energy Dome plant at Kudgi with Triveni Turbine as turnkey contractor, presented as a Make in India project.5919

Willow Rock jobs about 700 construction, 40 permanent5 Jintan phase two 2 x 350 MW19 NTPC Kudgi CO2 Battery 160 MWh9

Circular economy and end of life

Favourable

Plants are mostly steel and concrete, recyclable at end of life, and caverns can be sealed. Hydrostor captures and reuses condensed water. No significant hazardous waste stream is expected.4

Sources

  1. CEEC built World's First 300 MW Compressed Air Energy Storage Plant Connected to Grid at Full Capacity China Energy Engineering Corporation via Business Wire, 2025
  2. US DOE offers US$1.76 billion loan to Hydrostor for A-CAES California project Energy-Storage.news, 2025
  3. DOE's billion dollar bet: the largest-ever loan supporting long duration energy storage Renewable Energy World, 2025
  4. NTPC joins forces with Energy Dome for CO2 Battery deployment Energy Dome via Business Wire, 2025
  5. World's largest compressed air energy storage power station launched China Daily (Shandong), 2024
  6. Long-duration energy storage deployments rose 49% in 2025: Wood Mackenzie Utility Dive, 2026
  7. World's largest compressed air energy storage project breaks ground in China ESS News, 2024