Energy storage technologies for power grids can be categorized into four main types, each serving different roles in grid management:
1. Electrochemical Storage
Lithium-ion batteries dominate short-duration storage (up to 8 hours) due to declining costs and high efficiency. Flow batteries (e.g., vanadium redox) excel in medium-duration storage with minimal degradation over decades, exemplified by China’s 100 MW/400 MWh system. Emerging green hydrogen (via electrolysis) targets long-duration needs by converting excess electricity into storable hydrogen.
2. Mechanical Storage
Pumped hydro remains the largest-scale solution, ideal for long-duration storage and grid-balancing services, though geographically constrained. Compressed air energy storage (CAES) stores air underground, often paired with natural gas for grid-scale energy management, offering mid-duration discharge. Flywheels provide rapid-response frequency regulation but are limited to short bursts.
3. Electrical Storage
Supercapacitors deliver high power density and fast response times for momentary grid stabilization, despite high self-discharge rates. Superconducting magnetic energy storage (SMES) uses cryogenically cooled coils for near-instantaneous energy discharge, suited for premium power applications.
4. Thermal Storage
This includes systems that store excess energy as heat (e.g., molten salts) or cold (e.g., ice), later converting it back to electricity or using it directly for heating/cooling. These are particularly effective for long-duration storage and industrial applications.
Comparison of Key Technologies
| Technology | Duration | Strengths | Limitations |
|---|---|---|---|
| Lithium-ion | Short (≤8h) | Cost-effective, scalable | Degrades over cycles |
| Flow batteries | Medium | Long lifespan, scalable capacity | Higher upfront costs |
| Pumped hydro | Long | High capacity, proven reliability | Site-specific |
| CAES | Medium-long | Large-scale, grid services | Requires gas/geology |
| Supercapacitors | Instantaneous | Rapid response, long lifespan | High self-discharge |
| Green hydrogen | Long | Unlimited duration potential | Low round-trip efficiency |
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-main-types-of-energy-storage-technologies-used-in-power-grids/
