The company is offering 2.83 terawatt hours (TWh) of capacity, split into units, from May 1 until April 20, 2021.
It will take around 100 days to fill the 2.83 TWh, and another 20 days to empty it, allowing for over three churns in the year, the company said.
SSE Thermal owns and operates a fleet of flexible generation, energy-from-waste, and energy storage assets across Britain and Ireland.
SSE Thermal's two gas storage facilities at Atwick and Aldbrough on the East Yorkshire coast offer flexibility and hedging services to Britain and interconnected gas markets.
By Nina Chestney