Molten Salt Energy Storage


SolarReserve is the industry leader in advanced solar thermal energy storage technology. Molten salt is used both as a heat transfer fluid (HTF) as well as a thermal energy storage medium.

The molten salt mixture is both non-toxic and inert. Together with the SolarReserve technology design, the use of molten salt represents the most flexible, efficient and cost-effective form of large scale energy storage system deployed today. This storage feature enables stable and dispatchable power delivery without the need for any backup fossil fuel such as the natural gas needed for many other CSP technologies. SolarReserve’s experience with molten salt includes salt specifications, equipment metallurgy, tank foundation design and engineering, as well as initial salt melting and commissioning processes.


  • Molten salt is circulated through highly specialized piping in the receiver (heat exchanger) during the day, and held in storage tanks at night – requiring no fossil fuels
  • The tanks store the salt at atmospheric pressure
  • Use of molten salt for both heat transfer and thermal energy storage minimizes number of storage tanks and salt volumes needed
  • Molten salt is stored at 1050⁰F (566⁰C) until electricity is needed – day or night, whether or not the sun is shining
  • As electricity is needed, molten salt is dispatched from the hot tank through a heat exchanger to create super-heated steam which then powers a conventional steam turbine
  • The molten salt never needs replacing or topping up for the entire 30+ year life of the plant
  • Heat loss is only 1⁰F per day
  • The salt, an environmentally friendly mixture of sodium nitrate and potassium nitrate, is able to be utilized as high grade fertilizer when the plant is eventually decommissioned


  • Storage enables solar thermal power plants to operate just like a conventional fossil fuel or nuclear power plant, reliably generating electricity when it’s needed most - but without the associated harmful emissions and without any fuel costs
  • Solar thermal power plants with integrated molten salt energy storage can operate 24/7, proving baseload power for both on-grid and off-grid applications
  • Integrated energy storage provides the ability to shift electricity generation to meet different profile needs and deliver firm, reliable power at high capacity value
  • Molten salt thermal energy storage is the lowest capital cost energy storage system
  • Solar thermal power plants with integrated energy storage are cost-competitive with any new build coal, natural gas, or nuclear technology
  • Storage allows the facility to produce more than twice as much net annual output (megawatt hours) than any other solar technology
  • Firm output ensures a more stable and secure transmission system


By turning the sun into a 24/7 energy source, SolarReserve offers a realistic solution that can meet the global need for reliable, emissions-free electric power that is available around the clock and is a viable alternative to baseload coal, nuclear or natural gas burning electricity generation facilities.