UC Berkeley

Herein we present a concept of a high-temperature, thermal energy storage (HT-TES) system for large-scale long-duration energy storage (>10-hour discharge) applications. The system relies on tunable composite ceramic materials with high electrical conductivity and can output the stored energy flexibly as heat at 1100 degrees C or higher, and as electricity. We model the performance and cost of the system in a techno-economic analysis to identify key material and system properties influencing viability. For applications with daily operation (12-hour storage duration), we find achieving levelized storage costs below US Department of Energy’s 5 ₵/kWhe (1-2.5 ₵/kWhth equivalent) target by 2030 is possible. Candidate materials should have above 600-900 high-temperature cycle stability while offering at least 104 S/m of electrical conductivity. Our results suggest this system can economically store energy for weeks to months, or a longer discharge duration (96 hours) when coupled with intermittent charging using surplus renewable energy sources.