Solar Power Plant with Molten Salt Energy Storage

The Solana Concentrating Solar Power plant in Arizona has the ability to store solar energy in the form of hot saline water for up to six hours, allowing for electricity production at night. This is possible due to its thermal energy storage system consisting of six pairs of hot and cold tanks with a capacity of 125,000 metric tons of salt.

Salt is a cheap and abundant resource that has the ability to absorb and retain heat, and it does not evaporate even at extremely high temperatures. When the sun goes down and stops producing heat for the plant, a fluid exchanges heat with the molten salt tanks that have been heated during the day. The fluid then flows to steam boilers, where it heats water to create steam and enables the plant to produce energy.

Why you should care

Efficient energy storage is one of the primary challenges for scaling wind and solar power. Thermal storage allows this concentrating solar power plant to achieve higher efficiencies by generating electricity even when the sun is not shining. The molten salt in the Solana plant’s energy storage tanks is kept at a minimum temperature of 277 °C for up to six hours, which enables highly efficient production of steam throughout the night.

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