Clean Energy 101: Thermal Batteries

Thermal batteries store renewable electricity as high-temperature heat in abundant materials like graphite or bricks, providing a cost-effective alternative to fossil fuels for industrial processes requiring temperatures over 1,000°C. The technology supports grid stability by reducing renewable curtailment and offers a lower-risk alternative to hydrogen for industrial decarbonization. While facing challenges in wholesale electricity market access and infrastructure integration, the sector saw investment spike to over $350 million in 2024.

• Thermal batteries address the challenge of decarbonizing industrial heating, which accounts for approximately 20 percent of global energy consumption and often requires temperatures exceeding 1,000°C for processes such as steelmaking, glassmaking, and chemical manufacturing.
• The technology operates through a five-step process: charging with renewable electricity, converting that electricity to thermal energy via resistive heating, storing it in high-heat capacity media (such as bricks, graphite, or crushed rock), maintaining the heat through insulation, and delivering it on-demand.
• Thermal batteries are categorized into three main types: latent phase change (e.g., ice-based or cryogenic), sensible non-phase change (e.g., molten-salt, hot silicon, or graphite), and thermo-chemical (e.g., salt hydrate or adsorption solar heating).
• Compared to lithium-ion batteries, thermal batteries use abundant and cheap materials like salt and clay bricks, and they offer a less complex and lower-risk alternative to hydrogen, which faces challenges regarding transport, storage, and nitrogen oxide emissions.
• Financial investment in industrial decarbonization peaked at $5 billion in 2023, with thermal batteries specifically seeing a spike in new investment to over $350 million in 2024.
• Widespread adoption is currently hindered by two primary factors: the inability to access location- and time-specific wholesale electricity pricing and the difficulty of integrating new heat production into complex existing industrial facilities.

APA

RMI (2025). Clean Energy 101: Thermal Batteries. https://rmi.org/resources/clean-energy-101-thermal-batteries/

Chicago

RMI. Clean Energy 101: Thermal Batteries. 2025. https://rmi.org/resources/clean-energy-101-thermal-batteries/.

Wikipedia

{{cite report |author=RMI |title=Clean Energy 101: Thermal Batteries |date=3 February 2025 |url=https://rmi.org/resources/clean-energy-101-thermal-batteries/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2025clean, author = {{RMI}}, title = {{Clean Energy 101: Thermal Batteries}}, institution = {RMI}, year = {2025}, month = feb, url = {https://rmi.org/resources/clean-energy-101-thermal-batteries/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }