Pumped Thermal Energy Storage (PTES)

Detailed overview of innovation with sample startups and prominent university research


What it is

Pumped Thermal Energy Storage (PTES) is a technology that utilizes heat pumps and thermal energy storage (TES) to store electricity as thermal energy. During periods of low electricity demand or high renewable energy generation, electricity is used to power a heat pump, which generates heat and stores it in a TES system. When electricity is needed, the stored heat is used to drive a heat engine, generating electricity.

Impact on climate action

Pumped Thermal Energy Storage (PTES) under Thermal & Mechanical Storage enhances climate action by enabling efficient storage of excess renewable energy as heat. By providing dispatchable and grid-flexible energy solutions, PTES reduces reliance on fossil fuels, promotes renewable energy integration, and accelerates the transition to a low-carbon energy system, mitigating climate change impacts.

Underlying
Technology

  • Heat Pumps: Heat pumps are used to transfer heat from a low-temperature source to a high-temperature sink, effectively “pumping” heat to a higher temperature level for storage.
  • Thermal Energy Storage (TES): TES systems store the heat generated by the heat pump. Various TES technologies can be used, such as water tanks, molten salt, or phase change materials (PCMs).
  • Heat Engines: When electricity is needed, the stored heat is used to drive a heat engine, such as a steam turbine or an Organic Rankine Cycle (ORC) engine, to generate electricity.
  • System Integration and Control: PTES systems require sophisticated control systems to manage the operation of the heat pump, TES system, and heat engine, ensuring efficient energy storage and retrieval.

TRL : 5-6


Prominent Innovation themes

  • High-Efficiency Heat Pumps: Advancements in heat pump technology, such as the use of variable-speed compressors and advanced refrigerants, are improving the efficiency of PTES systems.
  • High-Temperature TES Materials: Researchers are developing new TES materials with higher temperature capabilities and energy densities, expanding the applications of PTES for industrial process heat and power generation.
  • Integrated System Design: Companies are developing integrated PTES systems that combine heat pumps, TES, and heat engines into a single, optimized package, simplifying installation and operation.
  • Hybrid PTES Systems: Hybrid systems that combine PTES with other energy storage technologies, such as batteries or compressed air energy storage, can offer greater flexibility and a wider range of grid services.

Other Innovation Subthemes

  • Advanced Heat Pump Designs
  • Next-Generation Thermal Energy Storage Materials
  • Hybridization with Battery Storage
  • Smart Grid Integration Strategies
  • Efficient Heat Engine Technologies
  • Modular PTES System Designs
  • Optimization of Control Algorithms
  • High-Temperature TES Solutions
  • Scalable Grid-Scale Applications
  • Industrial Process Heat Applications
  • Advanced Refrigerants for Heat Pumps
  • Decentralized Energy Storage Solutions
  • Integration with Renewable Energy Sources
  • District Heating and Cooling Solutions
  • Long-Duration Energy Storage Systems
  • PTES for Microgrid Applications

Sample Global Startups and Companies

  1. Malta Inc.:
    • Technology Enhancement: Malta Inc. specializes in grid-scale energy storage solutions using pumped thermal energy storage (PTES) technology. Their system stores energy by converting electricity into thermal energy, which is then stored in molten salt or other phase-change materials. During discharge, the stored thermal energy is converted back into electricity using a heat engine or other conversion technologies.
    • Uniqueness of the Startup: Malta Inc. stands out for its innovative approach to energy storage using PTES, which offers high energy density, long-duration storage capabilities, and scalability. Their system addresses the challenges of intermittency and variability in renewable energy sources by providing dispatchable and flexible storage solutions for grid integration.
    • End-User Segments Addressing: Malta Inc. serves utility companies, renewable energy developers, and grid operators seeking cost-effective and reliable energy storage solutions. Their PTES technology is suitable for large-scale renewable energy projects, grid stabilization, and peak demand management, enabling the integration of renewable energy into the grid.
  2. Echogen Power Systems:
    • Technology Enhancement: Echogen Power Systems develops advanced energy storage and power generation solutions based on thermal energy technologies. Their PTES system utilizes high-temperature thermal storage materials, such as molten salt or liquid metals, to store and release energy. The stored thermal energy can be used for various applications, including electricity generation, industrial processes, and district heating.
    • Uniqueness of the Startup: Echogen Power Systems stands out for its expertise in high-temperature thermal storage and power generation technologies. Their PTES system offers high efficiency, rapid response times, and scalability, making it suitable for grid-scale energy storage and flexible power generation applications.
    • End-User Segments Addressing: Echogen Power Systems serves utility companies, industrial facilities, and energy-intensive industries seeking reliable and cost-effective energy storage solutions. Their PTES technology can be deployed in conjunction with renewable energy sources, fossil fuel power plants, and industrial processes to improve energy efficiency and reduce emissions.
  3. Polar Night Energy:
    • Technology Enhancement: Polar Night Energy focuses on developing innovative energy storage solutions for remote and off-grid applications. Their PTES system utilizes low-temperature thermal storage materials, such as water or phase-change materials, to store and release energy. The system is designed to provide reliable and sustainable energy storage for off-grid communities, remote industrial sites, and microgrid applications.
    • Uniqueness of the Startup: Polar Night Energy stands out for its specialization in off-grid and remote energy storage solutions using PTES technology. Their system offers a renewable and environmentally friendly alternative to diesel generators and other fossil fuel-based power sources in remote locations, contributing to energy independence and sustainability.
    • End-User Segments Addressing: Polar Night Energy serves off-grid communities, remote industrial facilities, and microgrid operators seeking reliable and sustainable energy storage solutions. Their PTES technology is particularly well-suited for applications in Arctic and remote regions where access to reliable energy sources is limited, helping to reduce reliance on fossil fuels and support local economic development.

Sample Research At Top-Tier Universities

  1. Massachusetts Institute of Technology (MIT):
    • Research Focus: MIT is at the forefront of research on Pumped Thermal Energy Storage (PTES), focusing on developing advanced system designs, materials, and control strategies for efficient and scalable thermal energy storage solutions.
    • Uniqueness: Their research encompasses the development of novel heat transfer fluids, thermal storage media, and system architectures optimized for high energy density, rapid charging/discharging rates, and long-term stability. They also investigate the integration of PTES with renewable energy sources, waste heat recovery systems, and district heating/cooling networks to enhance overall system efficiency and reliability.
    • End-use Applications: The outcomes of their work have applications in grid-scale energy storage, industrial process heat, and building HVAC systems. By enabling flexible and dispatchable thermal energy storage, MIT’s research contributes to grid stability, renewable energy integration, and energy cost optimization, facilitating the transition to a low-carbon energy future.
  2. National Renewable Energy Laboratory (NREL):
    • Research Focus: NREL conducts cutting-edge research on Pumped Thermal Energy Storage (PTES), leveraging its expertise in renewable energy technologies, systems engineering, and grid integration to advance the development and deployment of innovative thermal storage solutions.
    • Uniqueness: Their research involves the design, modeling, and validation of PTES systems using advanced simulation tools, experimental testing facilities, and field demonstration projects. They also evaluate the techno-economic performance, environmental impact, and market potential of PTES technologies under various operating conditions and deployment scenarios.
    • End-use Applications: The outcomes of their work find applications in concentrated solar power (CSP) plants, waste heat recovery systems, and industrial process heating. By providing reliable and cost-effective thermal energy storage solutions, NREL’s research supports renewable energy deployment, energy access, and climate mitigation efforts worldwide.
  3. Technical University of Munich (TUM):
    • Research Focus: TUM is engaged in pioneering research on Pumped Thermal Energy Storage (PTES), leveraging its expertise in thermodynamics, fluid mechanics, and renewable energy systems to develop innovative PTES technologies for sustainable energy storage and utilization.
    • Uniqueness: Their research encompasses fundamental studies on heat transfer processes, phase change materials (PCMs), and thermodynamic cycles tailored for PTES applications. They also explore hybrid energy storage systems, thermal-to-electric conversion technologies, and smart control algorithms to optimize PTES performance and grid integration.
    • End-use Applications: The outcomes of their work have applications in district heating/cooling networks, industrial process optimization, and seasonal energy storage. By advancing PTES technologies, TUM’s research contributes to energy security, climate resilience, and decarbonization efforts, enabling the transition to a sustainable and resilient energy system.

commercial_img Commercial Implementation

PTES technology is still in the early stages of commercial deployment, with a limited number of pilot projects and demonstration plants in operation. However, the technology is gaining increasing interest as a potential solution for long-duration energy storage and grid-scale applications.