How much energy is stored in a coffee thermos? How about in a tray of ice cubes? Thermal energy storage technologies allow us to temporarily reserve energy produced in the form of heat or cold for use at a different time.

Take for example modern solar thermal power plants, which produce all of their energy when the sun is shining during the day. The excess energy produced during peak sunlight is often stored in these facilities – in the form of molten salt or other materials – and can be used into the evening to generate steam to drive a turbine to produce electricity. Alternatively, a facility can use ‘off-peak’ electricity rates which are lower at night to produce ice, which can be incorporated into a building’s cooling system to lower demand for energy during the day.

A well designed thermos or cooler can store energy effectively throughout the day, in the same way thermal energy storage is an effective resource at capturing and storing energy on a temporary basis to be used at a later time.