The round trip efficiency (RTE) of an energy storage system is defined as the ratio of the total energy output by the system to the total energy input to the system, as measured at the point of connection. The RTE varies widely for different storage technologies. A high value means that the incurred losses are low.
Reference Information
The typical RTE values for different technologies along with the source of information are provided below. If the reference provides a range of values instead of a single value, the median value of the range has been used.
- Lithium-ion (83%): W. G. Manuel, “Energy Storage Study 2014”, 2014.
- Vanadium redox flow (75%): V. Viswanathan, M. Kintner-Meyer, P. Balducci and C. Jin, “National Assessment of Energy Storage for Grid Balancing and Arbitrage, Phase II, Volume 2: Cost and Performance Characterization”, Sept. 2013.
- Sodium sulfur (75%): W. G. Manuel, “Energy Storage Study 2014”, 2014.
- Advanced lead-acid (85%): IEC, “Electrical Energy Storage: White Paper”, 2011.
- Flywheel (81%): V. Viswanathan, M. Kintner-Meyer, P. Balducci and C. Jin, “National Assessment of Energy Storage for Grid Balancing and Arbitrage, Phase II, Volume 2: Cost and Performance Characterization”, Sept. 2013.
- Compressed air (50%): IEC, “Electrical Energy Storage: White Paper”, 2011.
- Pumped hydro (81%): V. Viswanathan, M. Kintner-Meyer, P. Balducci and C. Jin, “National Assessment of Energy Storage for Grid Balancing and Arbitrage, Phase II, Volume 2: Cost and Performance Characterization”, Sept. 2013.