The Energy Storage Innovation prize is heating up, with the deadline to enter coming up on December 16, 2022. This week, we are focusing on a new type of eligible technology area for this prize: thermal energy storage.
Chemical and thermal energy storage focuses on containment technologies that are capable of harnessing energy for conversion to or from electricity. These thermal reservoirs can be discharged for a variety of applications, including electricity generation through a heat engine, industrial processes, or building uses. In addition, thermal energy may potentially offset demands on the grid that would otherwise manifest as electrical heating or cooling loads. –Energy Storage Grand Challenge
Thermal storage technologies have the potential to provide large capacity, long-duration storage to enable high penetrations of intermittent renewable energy, flexible energy generation for conventional baseload sources, and seasonal energy needs. All thermal storage technology areas are eligible for this prize, including proposals for phase change, low-temperature storage, high-temperature sensible heat, and thermal-photovoltaic innovations.
“Wind and solar power are now the lowest-cost electricity sources on the grid, but the sun always sets, and the wind doesn’t always blow. Energy storage is the next great challenge,” said Craig Turchi, National Renewable Energy Laboratory researcher. “Thermal batteries can address long-duration energy storage needs that enable a clean and reliable electricity system and, in many cases, also support commercial and industrial heat demand.”
A series of webinars led by the Department of Energy give an overview of thermal energy storage. Although these webinars focus on building applications, they offer an in-depth perspective on the current state of thermal technologies, including ice storage, hot water storage, and novel materials.
Example Research: Molton Salt Thermal Energy Storage
Thermal storage options include sensible, latent, and thermochemical technologies:
- Sensible thermal storage includes storing heat in liquids such as molten salts and in solids such as concrete blocks, rocks, or sand-like particles.
- Latent heat storage involves storing heat in a phase-change material that utilizes the large latent heat of phase change during the melting of a solid to a liquid.
- Thermochemical storage converts heat into chemical bonds, which is reversible and beneficial for long-term storage applications.
Often utilized by concentrated solar power plants, molten salt is a popular medium choice for sensible thermal storage systems due to its stability at high temperatures (~600°C). The molten salt is heated and stored in an insulated tank and can later be pumped through a heat exchanger unit to raise steam for a turbine. This approach can provide flexible energy storage production for a variety of applications.
