"Night Wind" Project to Test Electricity Storage in Refrigerated Warehouses
by Jeff McIntire-Strasburg, St. Louis, MO on 02.12.07
Critics of wind power are quick to jump on the issue of intermittence: essentially, wind turbines produce power when the wind blows, and that's not always when demand for electricity is at its high points -- solar power suffers from the same issue. Until we find a way to store the electricity produced when it's not needed, large-scale wind power is just a pipe dream, they argue. A group of Danish researchers will be testing out a novel solution to this problem: using refrigerated warehouses as giant "batteries" for electricity storage. According to Nature, the idea is pretty simple on its face:
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 as batteries — potentially storing 50,000 megawatt-hours of energy — and the food wouldn't melt.
Theoretically, it is simple; in reality, there are still a number of hurdles to overcome, including the proximity of coldstores to wind turbines. Still, researchers from other parts of the world believe the idea is worth testing, and could serve as a useful counterpart to other storage proposals, including plug-in hybrids and "heat pumps that convert electricity to hot water..." The cold storage concept has one particular strength, though: the infrastructure for it is largely in place. After Gutenberg notes that the US, for instance, might have as much as 900 GWH of "energy-banking capability," or roughly 2 hours of average US electrical consumption, and "We’d have to build out one huge amount of wind and solar power capacity to strain that."
Is this a promising project, or are there elements of cold storage researchers haven't yet considered? We'll know in a year and a half: the Night Wind project runs through June 2008. ::Nature via Slashdot, After Gutenberg and Roland Piquepaille's Technology Trends
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Energy storage? Just sounds like energy use at a different time.
"Energy storage? Just sounds like energy use at a different time."
Isn't that what storage is? Like when you store electricity in a battery (in a different form) and then use it later...?
I suppose but the idea doesn't fit the paradigm of a battery. It's not returning any energy, it is just not using energy at a peak time.
"I suppose but the idea doesn't fit the paradigm of a battery. It's not returning any energy, it is just not using energy at a peak time."
The electricity is converted to "cold", and that "cold" is used at the appropriate time (peak demand). It's a bit like a battery, but for "cold" instead of electricity. The end result is the same for the power grid, though.
It is, I'm just being picky on the terminology. I thought I just heard/read somewhere a similar idea. It was for cold climates and to turn off the refrigeration units when it was cold out and let nature keep things cold.
They've been doing an interesting thing in Chicago for years. They freeze a large amount of ice in a special building downtown during off peak electic hours and then use it to provide chilled water to buildings (many buildings use chilled water for their AC systems) for cooling during the day. My point the idea of using off peak electric to "store energy" to reduce peak demand isn't new.
Kinda cool: (no pun intended) Chicago, Illinois - A unique building in Chicago contains 5.5 million pounds of ice to create chilled water. Pumping this icy water around a 'district cooling' system cost-effectively cools 10 large Chicago office buildings, thus eliminating the use of 50,000 pounds of chlorofluorocarbons (CFC5) from the environment.
It is smarter use of available energy- not really storage, more energy buffer- I think energy buffer technology is something we will see a lot more of as we move to distributed systems, and depend more on intermittent power sources...this kind of thinking will amount to huge savings- and enable a smoother transfer to alternative energy sources. Where else can we buffer our energy system? (electric car batteries plugged into grid...Get a EEstor home capacitor)
Identical concept here to the Ice Bear posts done earlier on TH. What few non-engineers recognize, and what makes this particularly appealing as a technology, is that the efficiency of base load power generating plants is non-linear with respect to operational level. When a generating plant is bumping the peak of its output capacity, the emission per kW increase.greatly. Therefore, by making ice at night for the freezer plants, you increase the percent of the time that the base load generating plant that powers the freezer is operating at its "sweet spot", the place where performance is optimal. That has cost and environmental benefits obviously. Hope this helps. JL
Ice storage is one thing, but I have been to cold storage warehouses. They don't need a lot of cooling at night, but in the daytime there are deliveries and pickups, trucks coming and going, lights on and solar gain. I would think this would overwhelm the amount saved by cooling the stable, closed warehouse at night a degree or two.
The warehouse managers might complain that the fluctuation in temperature would cut product quality, so there should be a buffer in the warehouse as well, such as an ice block or gel ice. That would keep the temperature more level. This doesn't have to cut the amount of energy stored, just smooth the curve out a bit on the outflow. And in winter, they could wheel the ice/gel tank outside to freeze up, and wheel it back in and cut their load even more.
Utilities already have peak-load limiting agreements with many big customers. If warehouses are already signed onto this, their load cut time could just be lengthened.