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Wednesday, October 17, 2007 Fixing the Power GridBig batteries will fight blackouts and could make renewable power economically viable. By Peter Fairley
Large-scale power storage is crucial to our energy future: the Electric Power Research Institute, the U.S. utility industry's leading R&D consortium, says that storage would enable the widespread use of renewable power and make the grid more reliable and efficient. Recent announcements by utility giant American Electric Power (AEP), based in Columbus, OH, suggest that grid storage technologies are finally ready for commercial deployment in the United States. Last month, AEP ordered three multi-megawatt battery systems and set goals of having 25 megawatts of storage in place by 2010, and 40 times that by 2020. "That was a dream four or five years ago; now it is happening," says AEP energy-storage expert Ali Nourai. The AEP system uses a sodium-sulfur battery about the size of a double-decker bus (see below), plus power electronics to manage the flow of AC power in and out of the DC battery. Though new to the United States, the system has been used at the megawatt scale in Japan since the early 1990s; the battery was produced by NGK Insulators of Nagoya, Japan.
Charging Charleston: The utility American Electric Power (AEP) deployed this huge sodium-sulfur battery as part of a demonstration project in Charleston, WV. The battery provides 1.2 megawatts of power for up to seven hours, easing the strain on an overloaded substation. Trouble-free operation since installation last year convinced AEP that such energy-storage technology is ready for active duty. Nourai says that AEP and other U.S. utilities gained confidence in the economics and reliability of storage thanks to a demonstration project in Charleston, WV, where AEP installed a large battery system in June 2006. In Charleston, peak demand in both summer and winter had overloaded transformers at local substations, causing blackouts. Rebuilding the substations to accommodate more power could have taken as much as three years. Instead, AEP spent just nine months installing a battery system that charges when demand for electricity is low and can deliver up to 1.2 megawatts for seven hours when demand peaks. Two of AEP's new projects are slightly larger two-megawatt, seven-hour battery systems designed to provide similar quick fixes in areas with power-reliability problems. A battery in Milton, WV, for example, will provide backup electricity for customers in areas prone to blackouts from a weak power line. "When there is a blackout, the battery will pick up as many people as it can and continue to feed them," says Nourai. "They will not even know there was a blackout." The battery will postpone Milton's addition of a new substation and a high-voltage transmission line by five to six years. When AEP decides to make more permanent upgrades to substations or completes construction of a new power line--a process that can take five or six years--it will simply move the nearest backup battery to another choke point. "It can be lifted with a forklift and loaded onto a flatbed truck," says Nourai. "Within a week we can have it up and operational at another site in our system." |
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Storing Solar Power Efficiently
09/27/2007
Comments
nekote on 10/17/2007 at 8:52 AM
109
Sodium - a pretty tough element to deal with - corrosive, explosive with water, ...
Probably needs fairly extensive / extreme safety / environmental / fire precautions.
lowilliams on 10/17/2007 at 2:43 PM
17
asdar on 10/17/2007 at 2:58 PM
60
It's been tested, safety technologies have been put in place, and even in a catastrophic accident the public isn't put at risk.
The temperature isn't so high that it's not easily contained by common materials.
I think we need a storage system, like this, to turn the corner on grid tied home based alternative sources of energy.
urian1975 on 10/17/2007 at 9:10 PM
16
kittensteak on 10/18/2007 at 12:25 AM
2
Do you have any idea what the safety record of these units are?
dan_greenberg@esource.com on 10/22/2007 at 1:01 PM
1
bradwell on 10/29/2007 at 9:06 AM
1
The batteries have been thrown into fires and cars crashed into them, and they don't explode or anything (try doing that with a conventional battery!). Like all batteries, they have the potential to release their energy (even the lithium in Li-ion batteries is comparatively reactive with water and oxygen), but overall, they've demonstrated 15 years of reliable performance in Japan with dozens of MW scale units. I think we'll be seeing many more of these units in the US.
appratt on 10/17/2007 at 1:40 PM
1
DJTal on 10/18/2007 at 8:19 AM
109
Siphon on 10/18/2007 at 8:35 AM
65
With solar thermal dealing with most of the hourly/daily storage, to prevent using too much biomass (fuel vs food/other uses dilemma solved).
PV for peaking needs, and maybe some wind for winter loads if necessary. Some geothermal, small hydro, a little of this and a little of that.
Using renewable electricity for plug-ins is very efficient and causes very little pollution. And allows maybe some V2G to smooth things out even more.
With an aggressive energy efficiency program, demand can be almost stabilized.
What's missing in this article, is an expansion of the grid itself. In particular, a smart grid upgrade + a high capacity nationwide HVDC grid. With total infrastructure costs much less than 10% of what Iraq has cost already, what are we waiting for?!
DJTal on 10/18/2007 at 1:39 PM
109
Siphon on 10/18/2007 at 8:20 AM
65
Those also last longer because of lower operating temps and more stable chemistries. The only thing that has to be replaced every 5-10 years or so are the pumps. The electrolyte lasts a long time, and when it gets spoiled it can be mostly recycled.
Unfortunately these flow batteries currently use large amounts of rare elements, which impedes scalability. We need inexpensive designs that use common materials, but are still very efficient, durable and effective. Otherwise these things are restricted to niche markets.
There are other options as well, but my biggest bet is still on solar thermal with thermal storage, also mentioned in this article. Ausra is commercializing their underground thermal storage system which can be scaled rapidly and projected cost is about $3 per kWh(th) which is around $10 per kWh(e).
That's 15x cheaper than the most cost effective flow batteries, and 30x cheaper than the lowest estimate for these sodium sulfur batteries.
It also has a better round-trip efficiency than sodium sulfur batteries.
And underground hot water storage is much safer as well, as it's deep under the ground, and it's in the desert anyway.
[one could, of course, place the sodium sulfur batteries in the desert as well, if they really do pose such a serious hazard to people around it. Or even underground for that matter, but that's probably not very practical in the case of these batteries.]
asdar on 10/18/2007 at 9:57 AM
60
Underground thermal storage isn't even suitable for all areas. If we put the sodium storage in place it'll make an impact right away. It'll pay for itself, and it develops a technology that might have future branchings that will pay off.
I don't think we gain anything waiting for the next best solution.
Siphon on 10/19/2007 at 5:16 AM
65
The problem is that if they're too expensive, they are going to be niche.
There's plenty of suitable rock structures in the southwest though. This shouldn't be a major problem for underground thermal storage.
DJTal on 10/19/2007 at 8:38 AM
109
Siphon on 10/19/2007 at 2:01 PM
65
The point is, we're talking about large amounts of energy storage. It looks like solar thermal excells in this department.
bkf11 on 10/20/2007 at 5:57 AM
5
A solar thermal storage power station seems to be a great way to create baseload electricity but you can't just drop one into a suburban neighbourhood or onto a cloudy mountaintop beside some wind turbines - it just wouldn't be economical to use it for the purpose of taking out fluctuations in power output. Remember that power stations already vary their output according to demand - nothing new about that.
Benjamin
Siphon on 10/20/2007 at 10:06 AM
65
Solar thermal storage allows solar thermal plants to be load-following which is far more useful than baseload (baseload is a limited market; load-following is essentially an unlimited market).
Are you forgetting that we need to deal with the intermittency of renewable generation? These batteries can sure play a part in this, but my point is, in terms of the amounts of energy stored, solar thermal seems to have an edge. So for the brunt of energy storage, we should be looking into solar thermal rather than batteries for now. Maybe in the future they will miraculously come down in price, until then it's restricted to enhancing the grid.
DJTal on 10/20/2007 at 1:47 PM
109
bkshilo on 10/22/2007 at 6:22 PM
14
DJTal on 10/23/2007 at 3:38 AM
109
franquellim on 10/23/2007 at 1:26 PM
10
bkshilo on 11/30/2007 at 6:40 PM
14
lowilliams on 12/26/2007 at 5:53 PM
17
For a real 21st energy system ALL energy suppliers should immediately use the energy to electrolize water and place the product, hydrogen and oxygen, into a contenent spanning pipelines. The hydrogen will serve all energy users, the oxygen will be used to clean water and other waste. The pipelines will serve as hugh accumulators smoothing out all the up-and-downs of energy produced by renewables or what ever.
rhapsodyinglue on 12/30/2007 at 6:06 PM
54
Daniel from SA on 01/09/2008 at 9:04 AM
8