World's Biggest Battery Switched On in Alaska 103
windowpain writes "An article in the London Telegraph describes a 2,000 square meter 13,730 cell NiCad UPS that will provide backup power for the entire city of Fairbanks for up to seven minutes. 'This is enough time, according to ABB, to start up diesel generators to restore power, an important safeguard since at such low temperatures, water pipes can freeze entirely in two hours.' Now if they can just remember to keep it plugged in." Update: 08/28 14:58 GMT by M : A reader notes that the battery has enough juice for 12,000 people for seven minutes, and the city of Fairbanks has a population of over 80,000, so they couldn't keep the whole city powered up for even a minute.
12 stones! (Score:2, Informative)
if you were wondering about this like me ("what size of stone"
and i thought slugs were the weirdest invention in that backwards unit system...
please convert to SI!!!
Power vs. Energy (Score:5, Informative)
A typical average - at least in the lower 48 - is 1kw/household so 40 megawatts should handle 40,000 homes. For how long? We don't have that info other than the article's claim of 7 minutes. Assuming they got their signals crossed and mean that it can deliver 40 megawatts for 7 minutes then the batteries store 40,000kw * 7 minutes / 60 minutes = 4666kWh of energy.
For comparison, a AA nicad holds ~.75wh or .00075 kWh of energy so based on the preceding assumptions this battery bank is the equivalent of somewhat over 6 million AA batteries.
Another article [news-miner.com] indicates that the purpose is not to power the entire city but to carry the excess load when a single plant drops off line. Fairbanks does have outside feeds and multiple local plants just like the continental US but it has fewer of each so loss of a plant can cause a proportionately larger swing in the supply. It appears that this battery bank is really a load leveler, not a UPS.
CORRECTION TO WRITE-UP (Score:5, Informative)
FYI - I had family living in Fairbanks for a while so here is some trivia regarding the weather there:
Everyone must have three plug-in heaters in their car, one for the oil pan, one for the radiator, and one for the battery. All major shopping centers have outdoor outlets to plug your car into while you shop.
In addition to being wicked cold, their is essentially 0% humidity, this results in extremely high risk of static shock. And on a cold day you can actually throw hot coffee in the air and it fall to the ground as instant coffee.
The whole city is built on permafrost, so for any major construction they have to sink pilings into the ground to support the buidling once its ambient heat melts the soil below it.
The city is south of the arctic circle by a couple hundred miles, but there is small mountain nearby that if you drive to the top you can see the sun for 24 hours straigh on the summer soltice. THe favorite solstice activity is a city wide charity run.
In the Winter, there is nearby town that holds an annual statewide contest to guess when the river will melt sufficiently to allow a bouy to float freely. This event is called "break-up".
I went to the University of Alaska in Fairbanks... (Score:4, Informative)
Fortunately the city of Fairbanks was still with power and in a few hours they re-routed power to the University. This wasn't just good for keeping people from freezing in the dorms (the poor sots like me who didn't go home for the holidays) but it was very good for the Cray which was being threatened with imminent condesation...
If the whole city of Fairbanks lost power I wonder how people would have coped. I suppose families would have moved in together. Houses with wood stoves would have been very crowded... I wonder if there's even enough housing with other means of heating to support the whole town?
It's a start. Personally I prefer my own. (Score:5, Informative)
It will also keep your boat battery charged up for your next fishing trip. Note however, that this does not negate the need for some sort of a power filter on your computer. This would allow your gas appliances to work and your microwave.
Now I'm not a Y2K-store-Xyears-of-food-live-in-a-cave fruitcake. I just don't want to be the grasshopper, and I want to provide for my family during outages that seem more common than they should. An extended winter power-outage at -25deg F. adjusted my perspective. All you need is shelter/water/heat/food. Maybe a little love too...
Quicky UPS-sizing guide... (Score:4, Informative)
Batteries are rated in "Amp-hour" ratings. That is, they can (to a first approximation), deliver current "I" for time "t" where I*t= the rating. I say "to a first approximation" because the time-to-discharge as a function of current draw is not actually linear, but is really more like an exponential.
Of course, there's some efficiency lost in the DC-AC converter electronics. I don't have a clue what it is; perhaps 80% efficiency is good?
So you have a setup like mine: PC with 500W supply, monitor, printer, speakers. I would recommend NOT putting the printer and speakers on the UPS. Only essential equipment that needs power in order to shut everything down gracefully should be on the UPS.
My monitor eats maybe 50W, and my PC consumes 500W max: 550W worst-case.
According to this page [apcc.com], a APC BackUPS 650 (rated for 640VA), will operate a 400W load for seven minutes. With a perfect 120V output, that (perfectly resistive!) load is drawing 3.333A. With the 80% efficiency I mentioned above, it implies that the battery has an amp-hour rating of about 0.5Ah (500mAh). (0.5Ah * 0.8 eff)/3.333A = 0.12 hours (7.2 minutes).
My 550W load (assuming again that it's purely resistive) will draw 4.6A at 120V. This same UPS (assuming that the switching electronics can handle it!) will operate my machine for 0.087 hour (5.2 minutes), plenty of time to shut down.
So: to find the minimum-sized UPS you need, add up the load of the essential equipment, calculate the required current, and find a UPS with a big enough battery to provide you with a comfortable shutdown time.
Re:oh the humanity! (Score:1, Informative)
http://factfinder.census.gov/servlet/GCTTable?ds_
Re:hehe (Score:2, Informative)
Lets see 20 watts/hour(estimated) draw on a 40 megawatt system (40,000,000 watts) Gives you about 2,000,000 hours of music or about 83,333 days or about 228 years.