High Temperature Thermal Energy Storage Systems

Detailed overview of innovation with sample startups and prominent university research

What it is

High-temperature thermal energy storage (TES) systems are designed to store thermal energy at temperatures exceeding 100°C (212°F). These systems are crucial for various industrial applications, such as concentrated solar power (CSP) plants, industrial process heat, and waste heat recovery, where high-temperature heat is required for efficient operation.

Impact on climate action

High-Temperature Thermal Energy Storage (TES) Systems revolutionize climate action by storing excess heat energy for later use in industrial processes or electricity generation. By enhancing energy efficiency and grid stability, these innovations reduce reliance on fossil fuels, mitigate emissions, and accelerate the transition to a sustainable energy system.


  • Sensible Heat Storage: Materials like molten salts, concrete, and ceramics store thermal energy by increasing their temperature. These materials offer high thermal capacity and stability at high temperatures.
  • Latent Heat Storage: Phase change materials (PCMs) with high melting points, such as molten salts and metals, store thermal energy during phase transitions from solid to liquid and vice versa.
  • Thermochemical Storage: Thermochemical materials store thermal energy through reversible chemical reactions. Examples include metal hydrides and metal oxides.
  • System Design and Integration: High-temperature TES systems require specialized design and engineering to handle the high temperatures and pressures involved. This includes using materials with high thermal stability, designing efficient heat exchangers, and implementing safety measures.

TRL : 6-7

Prominent Innovation themes

  • Advanced Molten Salt Technologies: Innovations in molten salt technology are improving the thermal stability, heat transfer properties, and cost-effectiveness of molten salt-based TES systems.
  • High-Temperature PCMs: Researchers are developing new PCMs with higher melting points and energy densities, expanding the applications of latent heat storage for high-temperature processes.
  • Thermochemical Storage Materials with Improved Kinetics: Research is ongoing to develop thermochemical materials with faster reaction kinetics and higher energy densities, making them more suitable for practical applications.
  • Hybrid TES Systems: Hybrid systems that combine different TES technologies, such as sensible and latent heat storage, can offer advantages in terms of efficiency and flexibility.

Other Innovation Subthemes

  • Advanced Materials Development
  • Enhanced Heat Transfer Technologies
  • Hybridization of Storage Systems
  • Safety and Reliability Enhancements
  • Scalability and Modular Design
  • Integration with Renewable Energy Sources
  • Novel Heat Exchanger Designs
  • Thermochemical Reactor Innovations
  • Grid Integration Strategies
  • Thermal Energy Storage for Process Optimization
  • Materials Recycling and Sustainability
  • Advanced Control and Monitoring Systems
  • Thermal Storage in Industrial Applications
  • Smart Grid Integration
  • High-Temperature Storage for Power Generation
  • Next-Generation Storage Materials
  • Heat Recovery and Waste Heat Utilization

Sample Global Startups and Companies

  1. 1414 Degrees:
    • Technology Enhancement: 1414 Degrees focuses on developing high-temperature thermal energy storage solutions using silicon-based technology. Their systems utilize molten silicon as a storage medium to capture and store excess heat generated from renewable energy sources such as solar and wind power. The stored heat can then be converted back into electricity or heat on demand, providing a reliable and flexible energy storage solution.
    • Uniqueness of the Startup: 1414 Degrees stands out for its innovative approach to thermal energy storage using molten silicon, which offers higher energy density and operating temperatures compared to conventional TES systems. Their technology has the potential to significantly improve the efficiency and reliability of renewable energy integration, paving the way for a sustainable and decentralized energy future.
    • End-User Segments Addressing: 1414 Degrees serves utilities, industrial facilities, and renewable energy projects seeking cost-effective and scalable energy storage solutions. Their high-temperature TES systems are suitable for grid-scale applications, district heating, industrial process heat, and thermal power generation, addressing the growing demand for flexible and dispatchable energy storage.
  2. Brenmiller Energy:
    • Technology Enhancement: Brenmiller Energy specializes in thermal energy storage systems based on its patented Thermal Energy Cell (TEC) technology. Their systems use a combination of phase-change materials and proprietary heat transfer fluids to store thermal energy at high temperatures. This stored energy can be used for various applications, including electricity generation, industrial processes, and district heating.
    • Uniqueness of the Startup: Brenmiller Energy stands out for its innovative TEC technology, which offers high efficiency, reliability, and scalability for thermal energy storage. Their systems can store energy for extended periods without degradation, providing a cost-effective solution for integrating renewable energy and improving energy resilience in diverse environments.
    • End-User Segments Addressing: Brenmiller Energy serves utilities, industries, and municipalities seeking sustainable and resilient energy solutions. Their thermal energy storage systems are deployed in solar power plants, industrial facilities, and district heating networks, enabling the efficient use of renewable energy and reducing reliance on fossil fuels.
  3. SaltX Technology:
    • Technology Enhancement: SaltX Technology develops energy storage solutions based on salt hydrate technology. Their systems use a mixture of salt and water as a storage medium to capture and release thermal energy at high temperatures. This reversible reaction allows for efficient and cost-effective thermal energy storage, with applications in solar power plants, industrial processes, and building heating and cooling.
    • Uniqueness of the Startup: SaltX Technology stands out for its proprietary salt hydrate technology, which offers high energy density, long cycle life, and rapid charging and discharging capabilities. Their systems can be integrated with various renewable energy sources, providing a versatile and scalable solution for thermal energy storage in both grid-connected and off-grid settings.
    • End-User Segments Addressing: SaltX Technology serves a wide range of industries and applications requiring thermal energy storage solutions. Their systems are deployed in solar thermal power plants, industrial process heating, air conditioning, and refrigeration, offering significant energy savings, cost reductions, and environmental benefits.

Sample Research At Top-Tier Universities

  1. Massachusetts Institute of Technology (MIT):
    • Research Focus: MIT is a pioneer in the research on High-Temperature TES Systems, focusing on developing advanced materials, system designs, and control strategies for efficient and scalable thermal energy storage at elevated temperatures.
    • Uniqueness: Their research involves the exploration of novel phase change materials (PCMs), molten salts, and thermochemical reactions for storing heat energy at temperatures exceeding 500°C. They also investigate innovative heat exchanger designs, insulation materials, and integration with concentrating solar power (CSP) and industrial processes to enable high-temperature TES applications.
    • End-use Applications: The outcomes of their work find applications in CSP plants, industrial waste heat recovery, and district heating systems. By enabling reliable and dispatchable energy storage solutions, MIT’s research supports the integration of renewable energy sources, grid stabilization, and decarbonization efforts in the power and industrial sectors.
  2. National Renewable Energy Laboratory (NREL):
    • Research Focus: NREL conducts cutting-edge research on High-Temperature TES Systems, leveraging its expertise in renewable energy technologies, thermodynamics, and system modeling to advance the state-of-the-art in thermal energy storage.
    • Uniqueness: Their research encompasses the development of advanced TES materials, encapsulation techniques, and storage vessel designs capable of withstanding high operating temperatures and cyclic thermal stresses. They also explore the optimization of TES system performance, efficiency, and cost-effectiveness through techno-economic analysis, life cycle assessment, and experimental validation.
    • End-use Applications: The outcomes of their work have applications in concentrating solar power plants, industrial process heat, and grid-scale energy storage. By enhancing the reliability and flexibility of high-temperature TES technologies, NREL’s research contributes to reducing greenhouse gas emissions, enhancing energy security, and fostering the transition to a clean and sustainable energy future.
  3. German Aerospace Center (DLR):
    • Research Focus: DLR is at the forefront of research on High-Temperature TES Systems, leveraging its expertise in aerospace engineering, materials science, and thermal storage technologies to develop innovative solutions for high-temperature heat storage.
    • Uniqueness: Their research involves the investigation of advanced ceramic materials, phase change composites, and packed-bed reactors for achieving high energy density, thermal stability, and heat transfer performance in TES systems operating at temperatures up to 1000°C. They also explore advanced manufacturing techniques, system integration approaches, and thermal management strategies to enhance the reliability and efficiency of high-temperature TES technologies.
    • End-use Applications: The outcomes of their work find applications in concentrated solar power plants, industrial process heating, and renewable hydrogen production. By pushing the boundaries of high-temperature thermal energy storage, DLR’s research supports the transition to a sustainable energy system, enabling the efficient utilization of renewable resources and reducing reliance on fossil fuels.

commercial_img Commercial Implementation

High-temperature TES systems are being implemented in various commercial applications, including:

  • Concentrated Solar Power (CSP) Plants: Molten salt is widely used as a heat transfer fluid and storage medium in CSP plants, enabling electricity generation even when the sun isn’t shining.
  • Industrial Process Heat: High-temperature TES systems are being used to store and recover waste heat from industrial processes, improving energy efficiency and reducing emissions.
  • District Heating and Cooling: TES systems can be integrated with district heating and cooling networks to improve efficiency and flexibility, enabling the use of renewable energy sources and reducing peak demand.