Electricity and Gas for the World!

Gravel Stores Energy Like a Battery

Among the renewable energy sources which IDT Energy, as well as other ESCOs use to produce electricity are solar and wind power. Although clean and renewable, one of their drawbacks is that they are not always available. At night, of course, there is no sun shine, and the wind is also subject to times when it just isn’t there.

One of the goals of the research into making these green technologies more useful for our modern way of life is to store the renewable resource for use when the resource takes a break.

One way may be with a “gravel battery”, a new technology being developed by Isentropic, a five-man company in Cambridge. This is how it works. An electric current goes to a heat pump, a similar but bigger type of “compressor” used by your refrigerator to keep your food cold. The heat pump in your fridge takes the electricity to create a “heat split” which chills the inside of the fridge and heats the back.

The system Isentropic is developing uses a pump to heat argon gas to 500 degrees centigrade on one side and cooling the other side down to -150 degrees centigrade. The cold and hot gas is then passed through two enormous gravel tanks, heating one tank and cooling the other. The temperature difference in the gravel is how the power is stored.

When the power is needed the process is instantly reversed, causing the heat pump to work like an engine. When the extreme temperature differences are brought together, the engine turns, powers a generator, and creates electricity.

Clever, yes?

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