From: Adam <""4thwormcastfromthemolehill\"{at}the field.near
the bridge">

Typically it involves water in this case in it's frozen form:

http://www.nature.com/news/2007/070205/full/070205-9.html

"Refrigerated warehouses might soon be used to store not just food,
but gigawatts of electricity. A plan dreamt up in the Netherlands could see
the giant fridges acting as massive batteries. They would buffer swings in
supply and demand from electricity created from renewable sources.

The idea seems simple. Say you lowered the temperature of all large
coldstores in Europe by just 1øC during the night when electricity demand
is low, then let it rise 1øC by switching them off during the day when
demand is at peak. The net effect would be that the warehouses would act as
as batteries — potentially storing 50,000 megawatt-hours of energy — and
the food wouldn't melt.

That's the calculation of Sietze van der Sluis, head of refrigeration and
heating technology at The Netherlands Organization for Applied Scientific
Research (TNO) in Delft.

Van der Sluis is now leading a research project called 'Night Wind', to try
to put the idea into practice. Together with energy research groups and
suppliers in Spain, Bulgaria, and Denmark, he's looking at coldstores as a
potential solution to managing the intermittent and unpredictable flow of
renewable energy sources, such as wind power.

The problem with renewable power sources is that you get more electricity
on a windy day than on a calm one, or on a sunny day than a cloudy one.
This makes it difficult to integrate it into the grid, which must deliver a
steady flow of power and deal with peak demands. As a result many
renewable-power plants have to store their energy, by raising water to a
height or making hydrogen, for example, so they can
'save it for a rainy day'."

Adam

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