The efficiency of pumped hydroelectric storage (PHS) generally ranges from about 70% to slightly over 80% round-trip efficiency. This means that 70–80% of the electrical energy used to pump water to an elevated reservoir can be recovered during generation when the water is released to flow back down through turbines.
When compared to other energy storage technologies, pumped hydro is relatively efficient:
- Pumped hydroelectric storage: Typically 70–80% efficient, sometimes cited as “more than 80%” in practical implementations.
- Lithium-ion batteries: Usually around 85–95% efficient, which is higher than PHS, but lithium-ion batteries generally provide shorter duration storage (several hours) compared to pumped hydro that can deliver about 10 hours or more of electricity.
- Hydrogen storage: About 40–60% efficient, considerably less efficient than PHS.
- Compressed air energy storage: Around 60–65% efficient, also less efficient than PHS.
- Flow batteries: Can be about 70% efficient, roughly comparable but often lower than pumped hydro.
Pumped hydro is by far the largest-capacity and most mature form of grid energy storage globally, accounting for over 90% of installed energy storage capacity, with massive throughput and storage capability that surpasses other technologies by scale. Its longer discharge duration (typically about 10 hours) also makes it particularly suited for grid balancing and storing excess renewable energy for use during peak demand times.
Summary Table:
| Storage Technology | Round-Trip Efficiency | Typical Duration of Discharge | Notes |
|---|---|---|---|
| Pumped hydroelectric | 70–80% | ~10 hours | Largest grid-scale storage, mature technology |
| Lithium-ion batteries | 85–95% | Few hours | High efficiency, shorter duration |
| Hydrogen storage | 40–60% | Varies | Low efficiency, chemical storage |
| Compressed air storage | 60–65% | Several hours | Moderate efficiency |
| Flow batteries | ~70% | Varies | Similar to PHS efficiency, less common |
In conclusion, while lithium-ion batteries have slightly higher efficiency, pumped hydro provides cost-effective, large-scale, long-duration energy storage with competitive efficiency, making it the leading technology for grid-level storage globally.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-the-efficiency-of-pumped-hydroelectric-storage-compare-to-other-energy-storage-technologies/
