Integrated Thermal Energy Storage Systems

Detailed overview of innovation with sample startups and prominent university research

What it is

Integrated TES systems combine thermal energy storage (TES) technologies with other energy systems, such as renewable energy generation, heating and cooling systems, and industrial processes, to create a holistic and efficient energy management solution. These systems optimize energy usage, reduce peak demand, and enhance grid stability and resilience.

Impact on climate action

Integrated Thermal & Mechanical Storage (TES) Systems optimize energy storage, reducing reliance on fossil fuels and enhancing grid stability. By storing excess energy as both heat and mechanical energy, these innovations enable renewable energy integration, reduce carbon emissions, and accelerate the transition to a low-carbon energy system, combating climate change.


  • Thermal Energy Storage (TES): TES technologies store thermal energy in various forms, such as sensible heat, latent heat, or thermochemical energy. Examples include water tanks, ice storage systems, phase change materials (PCMs), and thermochemical materials.
  • System Integration: Integrated TES systems combine TES with other energy systems, such as solar PV, wind power, heat pumps, and industrial processes, to create a synergistic and optimized energy management solution.
  • Control Systems: Advanced control systems manage the operation of the integrated system, optimizing energy flows between different components and ensuring efficient charging and discharging of thermal energy.
  • Demand Response and Peak Shaving: Integrated TES systems can be used to shift energy consumption from peak demand periods to off-peak periods, reducing peak demand charges and improving grid stability.
  • Renewable Energy Integration: TES can be used to store excess renewable energy and provide a reliable source of heating or cooling, facilitating the integration of variable renewable energy sources into the grid.

TRL : 6-8 (depending on the specific technology and application)

Prominent Innovation themes

  • Hybrid TES Systems: Hybrid systems combine different TES technologies, such as sensible and latent heat storage, to optimize performance and cost for specific applications.
  • AI-Powered Energy Management: AI and machine learning algorithms can be used to optimize the operation of integrated TES systems, predicting energy demand and supply, and managing energy flows between different components.
  • Building-Integrated TES: Thermal energy storage systems can be integrated into building structures, such as walls and floors, to provide thermal mass and improve building energy efficiency.
  • Industrial Process Heat Integration: High-temperature TES systems can be integrated with industrial processes to store and recover waste heat, improving energy efficiency and reducing emissions.
  • Grid-Scale TES for Renewable Energy Integration: Large-scale TES systems can be used to store excess renewable energy and provide grid services, such as frequency regulation and peak shaving, supporting the integration of variable renewable energy sources into the grid.

Other Innovation Subthemes

  • Hybrid TES Architectures
  • AI-Enhanced Energy Optimization
  • Building-Integrated Thermal Mass
  • Industrial Heat Recovery Solutions
  • PCM-Based Thermal Solutions
  • Molten Silicon Storage Systems
  • Pumped Heat Energy Storage
  • Advanced Control Algorithms
  • District Heating Integration
  • Thermochemical Energy Storage
  • Smart Grid Interfacing
  • Cold Storage Facility Solutions
  • CSP Plant Thermal Storage
  • Off-Peak Energy Shifting
  • Long-Duration Storage Solutions
  • Thermochemical Material Innovations

Sample Global Startups and Companies

  1. Sunamp:
    • Technology Enhancement: Sunamp develops advanced heat storage solutions based on phase change materials (PCMs) and heat pump technology. Their integrated TES systems store thermal energy efficiently and release it on demand, providing heating, cooling, and hot water solutions for residential, commercial, and industrial applications. Sunamp’s systems offer high energy density, rapid response times, and compact designs, making them suitable for space-constrained environments and off-grid installations.
    • Uniqueness of the Startup: Sunamp stands out for its innovative approach to thermal energy storage using PCMs, which offer higher energy density and temperature stability compared to conventional storage methods. Their systems enable efficient energy utilization, load shifting, and renewable energy integration, contributing to sustainability and energy cost savings.
    • End-User Segments Addressing: Sunamp serves homeowners, businesses, and institutions seeking reliable and energy-efficient heating and hot water solutions. Their integrated TES systems are deployed in residential properties, commercial buildings, schools, and healthcare facilities, providing comfort, resilience, and energy savings.
  2. 1414 Degrees:
    • Technology Enhancement: 1414 Degrees specializes in thermal energy storage systems based on molten silicon technology. Their Integrated TES systems store heat at high temperatures using molten silicon as a heat transfer medium, offering long-duration energy storage capabilities and high energy density. 1414 Degrees’ systems are designed to provide grid stability, renewable energy integration, and industrial process heat applications.
    • Uniqueness of the Startup: 1414 Degrees stands out for its novel approach to thermal energy storage using molten silicon, which offers superior thermal properties and scalability compared to other storage mediums. Their systems enable efficient energy storage and dispatch, helping utilities, industries, and renewable energy projects balance supply and demand and reduce reliance on fossil fuels.
    • End-User Segments Addressing: 1414 Degrees serves utility companies, industrial facilities, and renewable energy developers seeking long-duration energy storage solutions. Their Integrated TES systems are deployed in grid-scale energy storage projects, renewable energy integration initiatives, and industrial applications requiring high-temperature heat.
  3. Malta Inc.:
    • Technology Enhancement: Malta Inc. develops grid-scale thermal energy storage systems based on a modular pumped heat energy storage (PHES) technology. Their Integrated TES systems store and release energy using a closed-loop process involving heat pumps, thermal storage tanks, and a heat transfer fluid. Malta’s systems offer scalable and dispatchable energy storage capabilities, enabling grid flexibility, renewable energy integration, and demand-side management.
    • Uniqueness of the Startup: Malta Inc. stands out for its innovative PHES technology, which utilizes low-cost and abundant materials to achieve high efficiency and scalability. Their systems are designed for grid-scale applications, providing long-duration energy storage and grid stability services to support the transition to renewable energy and decarbonization.
    • End-User Segments Addressing: Malta Inc. targets utility companies, grid operators, and renewable energy developers seeking cost-effective and scalable energy storage solutions. Their Integrated TES systems are deployed in grid-scale energy storage projects, renewable energy farms, and distributed energy resource (DER) installations, enhancing grid reliability and resilience.

Sample Research At Top-Tier Universities

  1. Massachusetts Institute of Technology (MIT):
    • Research Focus: MIT is a frontrunner in research on Integrated TES Systems, focusing on developing advanced technologies for storing and managing thermal and mechanical energy in a unified system.
    • Uniqueness: Their research encompasses the integration of thermal storage materials, phase change materials (PCMs), and mechanical energy storage devices (such as flywheels or compressed air systems) into hybrid energy storage systems. They also investigate novel system architectures, control strategies, and optimization algorithms to enhance efficiency, reliability, and scalability.
    • End-use Applications: The outcomes of their work have applications in renewable energy integration, grid stabilization, and energy-intensive industries. By developing integrated TES solutions, MIT’s research enables the efficient utilization of intermittent renewable energy sources, load shifting, and peak shaving, thereby enhancing grid flexibility and resilience.
  2. National Renewable Energy Laboratory (NREL):
    • Research Focus: NREL conducts cutting-edge research on Integrated TES Systems, leveraging its expertise in renewable energy technologies, grid integration, and energy storage to develop innovative solutions for enhancing system performance and cost-effectiveness.
    • Uniqueness: Their research involves the development and characterization of advanced materials, thermal storage media, and mechanical energy storage technologies for integrated TES applications. They also conduct techno-economic analysis, lifecycle assessment, and field testing to evaluate the performance and viability of integrated TES systems under real-world conditions.
    • End-use Applications: The outcomes of their work find applications in concentrated solar power (CSP) plants, waste heat recovery, and district heating and cooling systems. By advancing integrated TES technologies, NREL’s research contributes to improving energy efficiency, reducing carbon emissions, and promoting renewable energy deployment in various sectors.
  3. Technical University of Munich (TUM):
    • Research Focus: TUM is engaged in innovative research on Integrated TES Systems, drawing on its expertise in mechanical engineering, materials science, and energy technology to develop multifunctional energy storage solutions.
    • Uniqueness: Their research encompasses the design, modeling, and optimization of integrated TES systems for diverse applications, including renewable energy integration, thermal management, and waste heat utilization. They also explore novel heat exchanger designs, thermal energy conversion technologies, and hybrid storage concepts to enhance system efficiency and performance.
    • End-use Applications: The outcomes of their work have applications in building HVAC systems, industrial process heating, and solar district heating networks. By developing integrated TES solutions, TUM’s research supports the transition to a sustainable and low-carbon energy system, enabling the efficient utilization of renewable energy resources and the reduction of fossil fuel dependency.

commercial_img Commercial Implementation

Integrated TES systems are being implemented in various residential, commercial, and industrial applications around the world. For example, some supermarkets and cold storage facilities are using ice-based thermal energy storage systems to reduce peak demand charges and improve energy efficiency, while CSP plants utilize molten salt for thermal energy storage and electricity generation.