U.S. Department of Energy - Energy Efficiency and Renewable Energy

SunShot Initiative

High-Efficiency Thermal Storage System for Solar Plants

SENER logo Graphic of a rectangle shape to the left of a row or smaller rectangles stacked in two rows.

SENER is developing solid thermal energy storage (TES) systems that use heat-transfer fluids formed by combining high-thermal-capacity solids, such as graphite, with gases.

SENER, under the Baseload CSP FOA, aims to develop a highly efficient, low-maintenance and economical thermal energy storage (TES) system using solid graphite modular blocks for CSP plants.


The main objective is to evaluate a TES system able to store energy at temperatures greater than 800°C and that is robust enough to withstand the thermal cycles foreseen in a lifespan of 30 years with no parasitic energy consumption. SENER is refining the layout of the TES system, which is currently too large with too much piping to be economical.

The graphite material proposed appears to be superior to concrete for use as a TES storage medium. The project seeks to modify the graphite composition to increase the thermal conductivity and reduce the cost of the graphite, as these are the two biggest drivers in the cost of the system.


The system being developed under this award has extra capacity for higher temperatures and/or larger thermal differences compared with existing storage systems. The use of graphite allows for temperatures in the storage media approaching 1650°C. This technology can extend the operating range of thermal storage to significantly beyond that of molten salt (1650°C vs. 565°C), which could also have direct application to solar power towers.

Publications, Patents, and Awards

At this time, this project does not have published articles, patents, or awards.

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Learn about other DOE competitive awards for concentrating solar power research that are in progress.