U.S. Department of Energy - Energy Efficiency and Renewable Energy

SunShot Initiative

Innovative Phase Change Thermal Energy Storage Solution for Baseload Power

Infinia logo Illustration of two gray cyclinders with the one on the left showing a view of the top and the right one showing a view from the side.

Infinia is developing a thermal energy storage system for baseload CSP power generation. The system employs an innovative design to provide a unique integration of thermal salt, heat transfer fluid/device, and Stirling engine that improves performance and reduces system cost.

Infinia, under the Baseload CSP FOA, is developing and demonstrating a subscale system for baseload CSP power generation using thermal energy storage (TES) in a unique integration of innovative enhancements that improves performance and reduces cost.


The TES system being designed by Infinia is applicable to dish and power tower systems, allowing for high temperature (600° to 800°C), maintenance-free thermal energy storage. This integrated system allows large amounts of energy to be stored cost-effectively and efficiently through the use of phase change salts. The target levelized cost of energy (LCOE) for this dish system is $0.08–$0.09/kWh. LCOE projections for a 30 kW system are being updated in each phase of the project. Infinia has identified and organized tasks within each phase to:

  • Provide proof of concept by the end of Phase 1 with a 1-hour scale TES lab demonstration unit and preliminary system design
  • Complete system design and demonstrate a Heat Transport System (HTS) on sun by the end of Phase 2
  • Manufacture, deliver, and test a 75% capacity factor system by the end of Phase 3.


Infinia is pioneering the design of a 30-kW, 6-hour molten salt phase change TES system for dish systems with possible application to power towers. In the scale-up from 3 kW to 30 kW, the project uses a liquid metal pool boiler to transfer heat from the TES to the engine heater head. This is the primary innovation, resulting in much more dramatic heat transfer rates (10%+ increase) between the TES and the power block. The thermal conductivity enhancement within the salt is anticipated to be achieved with a future full-scale system based on Infinia's 30-kilowatt (kW) solar dish engine, but the proposed effort will focus on component and system development and demonstration at the current commercial 3-kW size. A secondary innovation is the inclusion of a nickel mesh inside the TES medium to improve thermal conductivity (60% increase) as the TES material solidifies and melts (three times faster).

Publications, Patents, and Awards

At this time, this project does not have published articles, patents, or awards.

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