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Utility stores wind power in huge batteries

September 12, 2007

One of the drawbacks features of renewable energy is that it often isn’t available in the same timeframe that we use it – that is, around the clock. Solar is available when the sun shines, and wind is likewise usually available with a solar-related periodicity. But what’s an efficient way of storing the energy for use when it’s not being generated? One east coast utility, American Electric Power, has invested in movable banks of sodium sulphur batteries, each about the size of a double-decker bus, to store wind-generated energy.

The batteries can each deliver one megawatt of power, which AEP says is enough to run a medium-sized shopping center for a little more than seven hours. The batteries are only about 80% efficient. Ouch. (The article says the batteries can operate at temperatures exceeding 800[deg]F. No idea why a utility needs that kind of temp range.)

According to the NY Times article, the batteries “will be used to smooth the power delivery from wind turbines. They can charge at night, when the wind is strong but prices are low, and give the electricity back the next afternoon, when there is hardly any wind but power prices are many times higher, company officials said. That strategy would reduce the amount of power generated from inefficient peak-demand units.”

Now let’s talk cost: “…$27 million for six megawatts of capacity, or about $4,500 a kilowatt, including the price of substation improvements. Building a gas turbine of that size to meet peak needs would cost substantially less. But the battery system would be able to store power made from wind, a form of generation that does not produce any carbon dioxide.” Sounds like the company may be positioning itself to sell carbon offsets. But more on that later.

Via gristmill.

Posted by Margery Conner on September 12, 2007 | Comments (8)

April 10, 2010
In response to: Utility stores wind power in huge batteries
hotel italien commented:

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August 3, 2009
In response to: Utility stores wind power in huge batteries
Meredith Poor commented:

Green power at 5.7 cents per KWH? www.austinchronicle.com/gyrobase/Issue/story?oid=oid%3A816816 "AE plans to formally propose the price change, reducing it to 5.7 cents/kWh for all current and future Batch 6 customers..." This has shown up in serveral news sites but is not mentioned on the Austin Energy website. Coal generated power in this part of the world is running about about 8.5 cents per KWH, so if a 2 cent per KWH subsidy is backed out the 7.7 cent rate is still competitive. Have we made the transition to competitive RE?


September 13, 2007
In response to: Utility stores wind power in huge batteries
Meredith Poor commented:

4 Scenarios ? 1) Battery is situated next to wind turbine (or other RE resource). Energy storage is 'gross', that is, before transmission, and transmission losses, but can be sold to in ?any direction?. 2) Battery is situated at 'junction', such as at a grid intertie. Storage is ?partial net?. Some additional energy may be lost in transmission, particularly if the direction of the energy flow is back to a consumer that is near the source of original generation. 3) Battery is situated at a ?local? substation. Storage is net of long distance transmission losses, consumption is presumed in the local subsystem. 4) Battery is situated at the ?point of load?, say inside a light fixture or air conditioner. Grid is not assumed to be 100% reliable; local storage ?cuts in? as appropriate. Storage is perfectly matched to load. Consumer is entirely responsible for storage and load allocation. Local RE resources (solar panel on roof) can be balanced between storage and load. In terms of overall efficiency (in both capital and energy), the last option makes the most sense. One wouldn?t do this with Lead Acid or NiCad batteries, however, or Li-Ion that like to burn up on trivial provocation. Newer NiMH have the self-discharge problem fixed. Some Li-Ion are much safer, if not necessarily as energy dense.


September 13, 2007
In response to: Utility stores wind power in huge batteries
Meredith Poor commented:

local storage ?cuts in? as appropriate. Storage is perfectly matched to load. Consumer is entirely responsible for storage and load allocation. Local RE resources (solar panel on roof) can be balanced between storage and load. In terms of overall efficiency (in both capital and energy), the last option makes the most sense. One wouldn?t do this with Lead Acid or NiCad batteries, however, or Li-Ion that like to burn up on trivial provocation. Newer NiMH have the self-discharge problem fixed. Some Li-Ion are much safer, if not necessarily as energy dense. ;


September 13, 2007
In response to: Utility stores wind power in huge batteries
Jonathan Williams commented:

Or taking a cue from Niagara Power, use the energy to pump water up to a storage pond, and then dump it through a turbine when needed.


September 13, 2007
In response to: Utility stores wind power in huge batteries
EV'er in ABQ commented:

Nickel iron is a robust topology but is one of the least efficient storage batteries, and has a high self-discharge rate.


September 13, 2007
In response to: Utility stores wind power in huge batteries
careba commented:

For investments of equipment and the hassle of permitting and the NIMBYs why not just connect to the grid. Have been involved in many large scale wind project that step up to the grid.


September 13, 2007
In response to: Utility stores wind power in huge batteries
bitbanger commented:

Why sodium-sulfur? The high temp is understandable - the sulfur has to be liquid for the battery to work. For high reliability fixed locations where size and mass are not important factors, why not Edison technology? Iron, nickel, and potassium hydroxide are not particularly expensive or polluting, and the batteries withstand severe electrical and environmental insults.

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