Different energy storage technologies vary significantly in their efficiency rates, often measured as round-trip efficiency (RTE)—the ratio of energy retrieved from storage to the energy put into it.
Efficiency Rates of Various Energy Storage Technologies
- Non-Flow Batteries: These batteries exhibit the highest round-trip efficiencies among large-scale storage technologies, reaching up to about 90% efficiency.
- Utility-Scale Batteries (General): In the U.S., the average monthly round-trip efficiency for utility-scale battery storage was around 82% in 2019.
- Pumped Hydro Storage (PHS): This large-scale, long-duration storage method typically achieves round-trip efficiencies between 70% and 85%. It remains one of the most efficient large-scale systems available.
- Flow Batteries: These have a slightly lower efficiency, with round-trip efficiencies ranging from 65% to 75%. Despite the lower efficiency, they offer advantages such as long cycle life and scalability.
- Liquid Air Energy Storage (LAES): This technology operates with round-trip efficiencies around 60% to 70%, making it suitable for long-duration storage but with moderate efficiency.
- Flywheel Energy Storage Systems (FES/FESS): Flywheel systems reach efficiencies between 85% and 87%, which is quite high, particularly for short duration and high power applications.
- Synthetic Fuels: Representing a chemical energy storage route, synthetic fuels have a much lower round-trip efficiency, around 30%, due to energy losses in conversion processes.
Summary Table of Round-Trip Efficiencies
| Technology | Round-Trip Efficiency (%) |
|---|---|
| Non-Flow Batteries | Up to ~90% |
| Utility-Scale Batteries | ~82% |
| Pumped Hydro Storage (PHS) | 70% – 85% |
| Flow Batteries | 65% – 75% |
| Liquid Air Energy Storage (LAES) | 60% – 70% |
| Flywheel Energy Storage (FES) | 85% – 87% |
| Synthetic Fuels | ~30% |
These efficiencies depend on multiple factors such as charging/discharging speed, storage duration, temperature, and system design, influencing the net energy losses during storage cycles.
In practice, technologies with the highest round-trip efficiencies (like non-flow batteries and flywheels) are favored for applications requiring frequent cycling and high energy return, while options like pumped hydro and LAES are more suited to large-scale and long-duration energy storage despite slightly lower efficiencies.
Overall, round-trip efficiencies for modern energy storage systems typically range from about 60% up to 90%, reflecting a balance between technology maturity, scalability, and application needs.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-efficiency-rates-of-different-energy-storage-technologies/
