The production of wind energy is quite variable, relatively unpredictable and not necessarily occurring at peak demand, thus as its use becomes more widespread it becomes more problematic to integrate it into the grid than conventional sources of power as it is not easily accommodated by switching on and off conventional energy suppliers, like coal fired power plants. The "Night Wind" project in the Netherlands uses an energy management methodology in which existing refrigerated warehouses are used to store wind energy produced during periods of low demand (at night) and then recover this energy during high demand periods (primarily during the day) thus relieving the grid of some of its demand during peak periods. An article in Nature described the process as follows:
The idea seems simple. Say you lowered the temperature of all large coldstores in Europe by just 1°C during the night when electricity demand is low, then let it rise 1°C by switching them off during the day when demand is at peak. The net effect would be that the warehouses would act as batteries -- potentially storing 50,000 megawatt-hours of energy -- i.e. store over twice the projected 2010 EU average hourly wind power production.
And as the refrigerated warehouses already exist, practically no extra cost should be needed to store as much as 50,000 megawatt-hours of energy.
The first tests will be done in the Netherlands this year. Wind turbines will be erected on site, and the warehouse's refrigeration system control will be adapted to store the produced wind energy during the night. These tests will be completed in 2008.
For daytime situations, the "Night Wind" system control will make decisions when to sell the produced energy and when to use it to operate the warehouse's refrigeration system.
Night Wind Project main goals:
- Integrating renewable energy resources into the European energy service network by providing new facilities for energy storage.
- Increasing the economic value of wind energy by providing means to deliver the energy at peak demand hours.
- Increasing the competitiveness of cold storage facilities by providing adding “energy storage” as an additional service to be provided for the European energy service network.
- The overall impact is that the project will offer a solution to integrate wind energy with energy storage in the European electrical grid, giving space to a further growth in the use of wind energy worldwide and a contribution to the Kyoto targets at the same time.
Nature adds some more details about the first tests of the Night Wind idea.
Later this year, Sietze van der Sluis, head of refrigeration and heating technology at The Netherlands Organization for Applied Scientific Research (TNO) in Delft and his team will start a demonstration project by setting up a wind turbine next to the Netherlands' largest coldstore, in Bergen op Zoom, a small town in the SouthWest of the country. It shouldn't be technically difficult, he says -- it's really just a question of developing software to match the temperature of the warehouses with electricity demand, turning the fridge on and off as the supply from the wind plant and the demand from consumers change during the day.
An introduction to cool energy storage, by my alma mater can be found here.
Thanks to jcwinnie at After Gutenberg for the tip.
This sounds like a very simple and inexpensive way to decrease our peak power usage. Lacking wind power it would seem that considerable power savings could be achieved by operating refrigerated spaces of all types on off peak power as much as possible (if they are not already), analogous to running water heaters on off peak power, but with a much larger payoff.