Laboratory-Scale Thermal Energy Grid Storage (TEGS) Prototype

Abstract

Grid-scale long duration energy storage will be necessary to maintain grid reliability in the US and beyond as intermittent renewables become the dominant source of electricity generation. An appealing long duration energy storage technology is thermal energy storage due to its low energy-based cost. One embodiment of thermal energy storage is the thermal energy grid storage (TEGS) concept, which is an envisioned graphite-based thermal energy storage system cycling between 1900-2400°C. Such a system would pump molten tin as a heat transfer fluid and use thermophotovoltaics to convert the thermal energy back to electricity. While many of these individual components have been demonstrated in isolation, there has yet to be a system which combines all these technologies into a working prototype. The focus of this work is creating this prototype and operating it at an intermediate temperature to uncover and overcome any system integration challenges that arise. In this work, a laboratory-scale TEGS prototype was designed and tested at temperatures up to 1000°C, uncovering challenges that are applicable to many high-temperature processes. By doing so, this work hopes to identify design criteria for similar high-temperature systems that must overcome some of the same challenges.