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Wednesday, October 17, 2007 Fixing the Power GridContinued from page 1 By Peter Fairley
Richard Baxter, author of Energy Storage: A Nontechnical Guide and chair of a conference held last week in New York City on investing in storage, says that AEP's new projects are a "good litmus test" for the industry. "Storage technologies are emerging as a viable, commercial-level product," Baxter says. The emergence of a grid storage market is drawing in new battery developers. These include Firefly Energy of Peoria, IL, which is using high-surface-area nanostructured electrodes to revive lead-acid technology, and lithium battery developer Altair Nanotechnologies, based in Reno, NV. In June, multinational utility AES agreed to buy an unspecified number of Altair's batteries; CEO Alan Gotcher says that Altair will deliver a one-megawatt, 15-minute prototype by the end of this year. AEP, meanwhile, is exploring a potentially more transformative role for storage: turning the ever-shifting power output of renewable resources such as wind and solar power into steady, dependable energy. The company plans to connect its third two-megawatt battery system to a group of wind turbines at an as-yet undetermined site. Nourai says that the goal is to learn whether batteries can smooth out short-term fluctuations in power flow from the turbines. If they can, utilities should be able to absorb larger levels of wind power on their grids. But Nourai says that AEP also wants to determine whether storing wind energy can boost its value. There are at least two ways that this could happen. Wind energy produced at night could be stored for delivery during peak hours of the day, when the price of electricity spikes. And if the power delivered by wind farms were more predictable, it would be more profitable. When an independent generator such as a wind-farm operator sells to power distributors, it must promise to deliver a certain amount of power at a certain hour. While the details vary greatly in different regional and national power markets, wind-farm operators can be penalized if they fail to meet their commitments because the wind didn't blow as hard as expected. Systems that store a fraction of a wind farm's output when the wind is blowing can eliminate most of this risk. Nourai notes that Japanese utilities are already installing energy-storage technologies to make wind power more reliable and profitable, thanks to government incentives that cover one-third of the cost of the storage system, and to the wider spread between Japan's day and night electricity prices. Nourai believes that NGK, which can currently produce 90 megawatts' worth of sodium-sulfur battery systems per year, is considering constructing a second factory to meet the resulting demand. Meanwhile, a study completed this year by Sustainable Energy Ireland, Ireland's energy-policy agency, concluded that time-shifting storage projects might already be profitable in Europe. However, an expert panel assembled by the Electric Power Research Institute last year judged that storage costs needed to drop below $150 per kilowatt-hour to make such time shifting economically attractive in the United States; a report issued by the institute this spring estimates that systems employing NGK's sodium-sulfur batteries cost $300 to $500 per kilowatt-hour. That cost differential has fueled recent interest in solar-thermal-power plants that capture renewable energy in the form of heat, which is easier to store than electricity. (See "Storing Solar Power Efficiently.") |
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Storing Solar Power Efficiently
09/27/2007
Comments
nekote on 10/17/2007 at 8:52 AM
115
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
62
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
116
Siphon on 10/18/2007 at 8:35 AM
95
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
116
Siphon on 10/18/2007 at 8:20 AM
95
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
62
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
95
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
116
Siphon on 10/19/2007 at 2:01 PM
95
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
6
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
95
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
116
bkshilo on 10/22/2007 at 6:22 PM
15
DJTal on 10/23/2007 at 3:38 AM
116
franquellim on 10/23/2007 at 1:26 PM
10
bkshilo on 11/30/2007 at 6:40 PM
15
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
55
Daniel from SA on 01/09/2008 at 9:04 AM
8