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Largest Sodium Sulfur Battery Powers a Texas Town
separsons writes "The largest sodium sulfur battery in America, nicknamed 'BOB,' can provide enough electricity to power all of Presidio, Texas. Until now, the small town relied on a single 60-year-old transmission line to connect it to the grid, so the community frequently experienced power outages. BOB, which stands for 'Big-Old Battery,' began charging earlier this week. The house-sized battery can deliver four megawatts of power for up to eight hours. Utilities are looking into similar batteries to store power from solar and wind so that renewables can come online before the country implements a smart grid system."
It's amazing the game of telephone that happens when blogs steal news stories from blogs that steal news stories from blogs.
Inhabitat: "Electric Transmission Texas ponied up $25 million to build the battery, and will add $60 million to build a second transmission line by 2012."
PopSci: "Electric Transmission Texas helped put the battery project together for around $25 million. But the utility has also agreed to build a second 60-mile transmission line to Presidio for about $44 million by 2012."
NPR: "The other solution for this town would be to build a second line, and that line would cost somewhere in the range of $40 to $50 million. And so a battery project in the $25 million range looks pretty attractive."
They all agree the battery costs $25mill, 2/3 agree that the 2nd transmission line will be built in 2012, and none of them agree on the price of the 2nd line.
"The house-sized battery can hold four megawatts of power for up to eight hours."
"Power" is not "held." Power is delivered. Energy is held. The unit of energy is joule.
This story originally came from an NPR interview. Here is a link.
Do you have a reference to the fact that the battery needs to run at 350C?
You could start with Wikipedia: http://en.wikipedia.org/wiki/Sodium-sulfur_battery
It seems a bit impractical to heat a house-sized building that much, especially when you have lost power.
Good insulation, and you don't heat the building, you heat the guts of the battery. Also, the lost energy is likely heating the battery.
I'm guessing a 4MW generator would take a couple of minutes, maybe 10s of minutes, to spin up to capacity.
Not the ones I've seen. (Hospital and nuke reactor backup.)
The whores get mad when the sluts give it away for free.
They can last about 2,500 complete cycles or 4,800 80% discharge cycles. (From the wikipedia article linked elsewhere). Presuming a power outage once a week requiring 80% discharge, it would last about 90 years, if the number of cycles is the only thing determining its longevity.
Look in any computer shop and you'll see NaS storage systems!
Agreed. A 4MW generator is going to run $1-2M, or you could buy one rebuilt for far less. For another million, you could install enough flywheel storage to last you until the generators can be brought online. Double it for added redundancy, and you're still talking 1/3 the upfront cost of the system.
No, Sodium-sulphur batteries scale down horribly. They need to run hot enough for the sulphur to be molten*, and keeping large things hot is easier than keeping small things hot, as the thermal energy scale with the cube of the size, but the escaped heat scales with the square. I don't know how small they can get, though.
*According to wikipedia, they need to run even hotter, 300-350 degree celsius
Call me old-fashioned, but I'd go 100% eco with a gerbil in a wheel or a hand crank if the demand doesn't exceed 4mW.
Reportedly many communities in Alaska are serviced by power generated by massive diesel generators.
Well of course they are. Diesel is the default conservative power source for remote communities in Australia but photovoltaics are moving in. Solar power may not work as well in Alaska but wind power may do the job instead. Combine that with a BoB and you have a good reliable power supply.
http://michaelsmith.id.au
So you're saying instead of smelting metal, making concrete, and paying construction workers to build the battery, it might be more cost effective to pay that same smelting facility, concrete making plant, and construction workers to provide a few hours of power for this town every week or so?
I doubt this project has anything to do with "renewable" but all to do with convenience of not having to lose power for a few hours every few weeks. Sure those few hours may be 10x as expensive as normal, but, eh, you don't have to adjust clocks on all those VCRs every week.
"If anything can go wrong, it will." - Murphy
Let's do the math here.
The article suggests the battery can put out 4 megawatts for 8 hours. So that's 32,000 kilowatt-hours. My electricity here costs about 7 cents a kWh, so that BOB can hold almost $225 worth of electricity. At a cost of many millions, that does not sound like very economical power per kWh!
For example, your basic Honda generator can run for two thousand hours, putting out 1,500 watts, before the little putt-putt engine needs an overhaul. So that's about 3,000 kilowatt-hours for $400. Let's assume the power fails ten times a year, so you'd wear out 10 Honda generators per failure (avg), at a cost of $4000 per, or $40,000 per year. By comparison BOB's cost of financing in itself is going to be at least $3 million a year, not to mention maintenance.
So these poor sods are paying about 75 times as much as they should.
( Not to mention that generators are much more economical in larger sizes )