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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."
the battery would cost 25M, while a second transmission line would cost 60M. o_O
Yes, I'm left. You have a problem with that?
A watt is a unit of power not energy, that'd be 115 gigajoules (or 32 MWh if you're lazy)
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.
so it holds 32MW
No - it can hold 32MWh (=115.2GJ). Batteries hold energy not power. Since power is energy per unit time you have to multiply it by a time to get energy.
"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.
Not based on the $25 million sticker price: that's just bullshit accounting. I'd like to know the Joules expended in the extraction, refining, shipping and construction of this thing, including the energy required by the workers, then let's compare that to the energy that it will actually store and deliver over its working life.
Eventually, we are going to have to start asking these questions about "renewable" generation and storage, because you can only hide a net energy loss in the books for so long, until the fossil fuels that subsidise these energy sinks start to run out.
If you were blocking sigs, you wouldn't have to read this.
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!
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.
That is 10-15 years when used as a night-time backup for solar collection.
This might be useful.
-Todd
Omne ignotum pro magnifico.
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
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 )