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Storing Wind Power In Cold Stores
Roland Piquepaille writes "According to Nature, a European-funded project has been launched to store electricity created from wind in refrigerated warehouses used to store food. As the production of wind energy is variable every day, it cannot easily be accommodated on the electrical grid. So the 'Night Wind' project wants to store wind energy produced at night in refrigerated warehouses and to release this energy during daytime peak hours. The first tests will be done in the Netherlands this year. And as the cold stores exist already, practically no extra cost should be incurred to store as much as 50,000 megawatt-hours of energy. Here are additional details and a picture illustrating this brilliant idea."
Well, this usage pattern resembles much the old idea of a pumped storage power plant (Pumpspeicherkraftwerk), a hydroelectric powerplant where the water, which is used in high load times to produce electric power, gets pumped back uphill to a reservoir by use of the excess power of the basic load power plants like coal or nuclear driven ones.
This is done for decades now in the european grid. I had the opportunity in the late sixties to visit such a power plant at Schruns/Tschagguns in Vorarlberg in Western Austria.
It's a very impressive installation with a entire delivery height of more than 2000m (6000ft) in two stages. In the exhibition is also an impressive display of the entire european powergrid.
CU
Maybe you are joking, but this as nothing to do with refrigerating electricity. It's about utilizing wind power to refrigirate during the night to be able to stop refrigirating during the day. Why? Because during the night, wind power over produce so it would be wasted! This is a simple idea but that can make a difference.
It reminds me about nuclear powerplants coupled with hydroelectricity. Nuclear power gives a constant output, but cannot be stopped shortly. So when they are overproducing, they pump water up transforming wasted energy in potential energy.
I might have taken physics a long time ago, but we learned that you make things colder by removing energy. So there can be no such thing as cold energy storage. You can consider a cold store to be like a vacuum storage tank as it creates a difference in energy which like electricity creates potential to cause energy in the form of heat to flow. It does make sense, however, to offset energy consumption from peak hours by this method. I'd seen a design discussed in the late 70's at Orange Coast College (Calif) for chilling a cold-brine in storage tanks below office buildings, then cycling the air condiditon pipes and transferring heat from the building and warming the cold brine. They had put the whole campus on a energy management system, driven by the mainframe, and all written in APL.
Yes, it is being done in northern L.A. county.
o .jsp?osti_id=7092283
http://en.wikipedia.org/wiki/Castaic_Dam
http://www.osti.gov/energycitations/product.bibli
It's Roland the Plogger, wrong as usual, spamming to promote his blog. The Slashdot editors gave him two links this time, one without a "nofollow". Ka-ching!
OK, now the real info. Thermal energy storage has been around for years. There are thousands of installations. It's used when there's a big difference between day and night power rates. During the night, water is chilled, or ice frozen; during the day, the cold water is used for air conditioning. See Thermal Energy Storage Strategies for Commercial HVAC Systems for details on how to configure such a system. Also see CALMAC, which makes such gear. It was a spinoff from their ice-rink equipment business.
I know Idaho Power has been doing this for at least a couple of years. They pay farmers to turn their irrigation wells off during peak periods. This is just a way to reduce demand during heavy usage.
c iency/Irrigation/irrigationPeakRewards.htm
http://www.idahopower.com/energycenter/energyeffi
I think the question is also how many stores Can do this?
I work in the IT section for the biggest refrigeration company in the Netherlands, and from what I've seen every type of food has an specific storage temperature. Apparently a 2 degrees Celcius difference will make a big difference in the quality of food.
home
This is done a lot in Norway,
There they have double water dams/basins one high one low.
During peak hour the water is rushed down for electricity.
During night they buy cheap French nuclear energy to pump water back.
We called this making green energy from nuclear energy
(btw i am not against this scenario, but the energy is not really green )
Also a lot of energy is lost in the transportation from France to Norway
Better solution, combine it with windmills on the mountain ridges
There are no stupid questions, Just a lot of inquisitive idiots. (from a good friend)
RTFA. They're not storing energy as heat and then attempting to recover it, they're modulating the energy usage of the cold store to buffer the grid. Cool down the store to -25 C during peak supply hours (which often don't coincide with peak demand), and you can switch off the refrigerator and let the temperature rise to -23 C during off-peak supply hours. This is beneficial regardless of whether the grid is powered by wind, solar or fossil fuel plants; wind power is just the sales pitch.
You can't store "cold". The concept of 'cold' is just a simpler way to describe a thermal vaccuum - or a 'heat vaccuum. O Kelvin is just the thermal equivalent of a perfect vaccuum. The quantity of heat energy in a given space is what determines how cold-or hot- something is. Heat is the measured energy, and 'cold' is simply the absense of heat. Therefore, you cannot store the absense of something.
Wheather something feels cold or hot to us is measured by how hot or cold it feels. But, regardless of how cold it feels, there is still heat present-evein in ice or frozen ammonia. Heat content only reaches zero at 0 degrees Kelvin.
I'm not a physicist, but I think of the concept of 'cold' or 'coldness' by defining 'cold' as a "Thermal Vaccuum".
Knowing Google's lust for data collection, the Soviet Union is still alive and well inside the psyche of Sergey Brin....
I'm not sure how things are in America right now, but in Australia, they're rolling out a scheme called 'Time of Use'. Meters are automatically read every 30 minutes, or every 15 for large usage sites, and you're charged based upon the time that you use the energy. Currently it's split into 3 blocks.. Peak (business times) shoulder (evenings) and off-peak (nights, weekends) and differing rates are set for each period.
Energy Australia charge 22c/kwh for Peak, 8c/kwh for Shoulder and 4c/kwh for Off-peak.
Not as elaborate as your suggestion, but far more suitable for the average home user. It would probably benefit such 'cold stores' too, because I wouldn't imagine it would make much difference whether they're -20 or -40, so they could cool right down during the night, then use less energy during 'peak' hours. I would guess future developments might see small sites charging batteries during the night to power appliances through the day.
This has been implemented near Cape Town in South Africa. During the evenings, hen demand for electricity is low, they pump water from a resevoir on the cape flats (i.e. nearly at sea level)(google maps link) up to the top of a nearby mountain (link to it on google maps. Then during the day, when the electricity is needed, they let the water flow back down and power a turbine generating surplus for the grid. I think this was implemented since pretty much all of cape town's electricity is supplied by Koeberg nuclear power station (when the turbines aren't breaking down), and from what i can gather, the electrical output from a nuclear plant is pretty constant and would otherwise be wasted if there was not some way to temporarily store it during quiet times for use in peak times.
Actually, I was once speaking to a farmer who owns the farm that the upper resevoir is located next to, and he pointed out a large many-story high concrete pillar (you can see it in the google maps link to the upper resevoir i inserted earlier in this post, to the lower right hand corner of the dam). He reckons, and i have no reason to doubt him, that its there to absorb the backward wave of water that is created when the downward flow is shut off each night. The way he explained it was its almost like a super large tidal bore flows back up the pipeline that was drilled through the mountain to the lower reservoir. Supposedly it would spout a column of water about 50 meters into the air otherwise. Anyway,thats totally irrelevant to the article, just thought it would make the links a bit more interesting.
The reason this matters for wind power follows:
Wind power is notoriously unreliable. A coal power plant can be predicted to always give out X amount of energy per minute (hour/day/whatever). Wind power, however, cannot. As weather is wont to do, it changes wildly and unpredictably during any given time span.
This method would allow cold storage units to use wind power to chill their goods during the night using "unpredictable" wind power, causing them to require less conventional power. That's how and why it works, in short. RTFA to figure it out if this doesn't help.
I had thought it was this project that actually stores off-peak power and then uses it during peak. It works based on this technology but uses wind power so that the variability can be managed.
Love it,
There seem to be many April magazine Articles that float around for years. My all time favorite is the one about 10^40 bits in a crystal or maybe it was 10^60 bits. It was enticing people into april 1 mode for years after that - spawned a number of subsequent professional articles too. All you need for a crystal is something somewhat larger than the earth - and some interface circuitry. Those who shoulda known better tended to be those who were the last to know.
This may not be quite so similar but it's definitely no new idea to store energy from production time to usage time. I guess with higher temp superconductors, maybe a nice refridgerator might be in order.
The big problem this stuff tries to address is based on the factor that peak electric loading occurs mid-day - when it's hot out, most everyone is awake and working. It is a serious problem and peak demand electricity has been a serious cost factor. Solar panels do offer peak output mid day so can help by selling some of their rather expensive electrons at primo prices. Wind often is strongest with the coastal breezes in mornings and evenings - due to unequal heating rates of water versus land.
Unfortunately, for every conversion of energy - there are thermodynamic penalties that must be paid and cannot be overcome using whatever particular technique happens to be employed in that particular circumstance. The notion of using energy in heat (or lack there of for cold) is particularly bad in cases where the resulting energy needs are in other forms - such as needing electricity again. Thermodynamic efficiencies for heat engines are a factor of the difference in temperatures between heat source and sink - and the lower the differences - the less efficient it can be.
Something as simple as cooling down commercial refridgerators at off peak hours is probably a good idea both from energy savings standpoint and from cost standpoints - assuming the insulation is sufficiently good to keep out the heat and permit a net savings. As for new innovatinve ideas it hardly seems to be something worthy of more than a passing mention in some grocery store checkout line magazine article about 10 ways to reduce your corporate electric bill.
In some areas of the country, there are systems with devices tied to electric meters that offer another, slightly more intrusive alternative which is essentially to have the equivalent of an old pre text message vintage pocket pager wired to a power relay. When the little pocket pager radio device is activated, the relay shuts off the power to the customer device for about 15 minutes. Typically, it's big ticket items for consumers like electric waterheaters, airconditioners and irrigation pumps (for farmers). This is called load shedding and it's used to minimize some of that expensive daytime peak power. One can create a rolling temporary shutdown that can shed a few million killowatts continually. Often these systems are involved with tens of thousands of customers and cover areas that could be whole states.
Like the refridgerator at night thing, it doesn't tend to save energy, but rather to distribute it around to reduce the peak load - sometimes at the expense of actually increasing the overall usage.