In their July 16th piece on solar energy technology in The New York Times, Andrew Revkin and Matthew Wald wrote that, "With more research, the solar thermal method might allow for storing energy. Currently, all solar power is hampered by a lack of storage capability." They are certainly right. In fact, a lack of storage capacity hampers a lot of things.
While there's been a lot of talk about coupling energy storage to solar (and wind) power, there are additional reasons for addressing our lack of storage capability. In fact, storage technologies can act as a "shock absorber" for the whole grid and can help address some of the key challenges facing the industry, including efficiency, reliability, and security. Simply put, energy storage is good for the grid.
The current electric power system is built around a central tenet: electricity must be produced when it is needed and used once it is produced. Bulk energy storage technologies break this antiquated linkage by allowing operators to produce and store electricity for later use -- as one would in other commodity markets.
Bulk energy storage also benefits all of us by creating a reserve that could be tapped in case of national emergency, much like the petroleum reserve. After all, our entire economy -- including our national defense capability -- runs on electricity. If key parts of the grid are taken out, and there is no electricity reserve at the ready, what happens then?
Emergency back-up power more often than not means diesel generators, and as we saw during the blackout of 2003, many diesel generators either couldn't get up and running or ran out of fuel before the lights came back on.
More specifically, however, storage benefits the energy consumer by providing a risk-management strategy, and it benefits the energy generator by making its assets more productive and efficient. As electricity demand continues to increase over time, existing generation assets must achieve greater efficiencies -- for both market and environmental reasons.
The amount of electricity flowing through the grid at any one point is determined not only by consumer demand but by physics as well. The grid itself requires a certain level of electricity flow in order to maintain its integrity. Ramping power up or down without taking grid requirements into consideration risks destabilizing the grid and costs money. So, during off-peak hours, coal facilities ramp down their utilization rate while nuclear facilities provide the baseload power needed to stabilize the grid. As additional power is needed, coal facilities are instructed to increase generation to meet demand. (Whether you like coal or not, by capacity coal-fired plants represent the largest fleet of power facilities). This process is called load following.
Coal plants follow the load requirements of the grid by ramping up or down as needed. The problem with this is that it wreaks havoc on coal plant systems, lowers overall efficiency, increases O&M budgets with additional maintenance, and results in shorter life spans of critical equipment.
However, if coal plants were not required to ramp down during off-peak periods -- nighttime -- but could instead continue to generate power and store it for release during the day, these facilities would not be required to perform as much of the load-following role as they currently do. Instead, power generators can provide power in long-duration (and more efficient) discharges and then use stored energy to provide low-cost ancillary services such as load following and spinning reserves. This would increase a plant's capacity factor, a measure of asset productivity, and reduce systemic stress and the costs required to address that stress. Utilized in this manner, large-scale storage helps offset the need for some additional peaking capacity, but is focused more as a system optimizer than generation replacement.
Coupled with storage, a generation facility can also gain much-needed flexibility during the critical scheduled "outage" seasons (when units are taken out of service for planned maintenance) of the spring and fall to avoid spot make-up purchases.
Other optimizing roles for storage include improving the economic and environmental profiles of fossil assets by reducing regular dispatch and cycling costs. Storage lowers the fixed-cost-per-unit output, improves the economics of these capital-intensive facilities, and helps them to run in a more efficient -- both operationally and environmentally -- manner that lowers overall per-unit production cost.
And, of course, coal facilities must also deal with their impact on the environment. Because emission limits (NOx restrictions, etc.) can constrain a power facility from operating maximally during peak times such as summer, they are often forced to operate at partial power. Unfortunately, when operating at partial power, plants are less efficient and have higher emissions per unit of heat input. Storage could help these facilities reduce their total emission per unit of output by shifting some production to the evening when the facility could run at its rated -- instead of partial -- generating capacity. And, by producing more power at night, air quality near the coal facility is improved since ozone-induced haze, a by-product of NOx, O2, and sunlight, is less likely to develop.
‘Heretic’ battles straw man
Comments
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David Roberts Posted 7:58 am
17 Jul 2007
grist.org
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Jon Rynn Posted 2:42 pm
17 Jul 2007
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GreyFlcn Posted 5:40 pm
17 Jul 2007
(Yes, G2G, not V2G)
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Jon Rynn Posted 1:11 am
18 Jul 2007
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ac5p Posted 1:30 am
18 Jul 2007
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SustainableGreen Posted 2:35 am
18 Jul 2007
Gee, it doesn't matter whether you speak of big or small. And sustainable sources are essential. You folks almost COMPLETELY ignore home systems and sustainability. And why the fuck are we STILL discussing COAL? Have you learned NOTHING about coal?
Are all of you STILL slaves to the mentality of electricity as a commodity? Are you lobotomized engineers (yeah, that's redundant!) with no ability for critical thinking?
Engineers + Box --> Nowhere
Greed will practically always drive utilities to confine sources into monopolies and customers into those sources. It is part of marketing. To the extent we follow their marketing crap we are doing no better.
Hey, Jon Rynn: I can only speak for lead-acid batteries since this what I use at home, and I vetted them years ago. These are highly recycled (as highly as any consumer product) by customers and suppliers. Plastic, lead, acid all get reused. I suspect it is a matter of scale--the larger the battery the easier the handling and the better the incentive to recycle. It may be that large new-tech batteries should only be leased to customers (whether utility or residential), so the suppliers have better control over recycling.
Wind and Sun on all scales, with storage on all scales, is the way to sustainability--on all scales.
David
Sustainability For Life
Messages done with sustainable energy, with Wind and Sun!
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Jon Rynn Posted 3:00 am
18 Jul 2007
A new type of a room-size battery, however, may be poised to store energy for the nation's vast electric grid almost as easily as a reservoir stockpiles water, transforming the way power is delivered to homes and businesses. Compared with other utility-scale batteries plagued by limited life spans or unwieldy bulk, the sodium-sulfur battery is compact, long-lasting and efficient.
Using so-called NaS batteries, utilities could defer for years, and possibly even avoid, construction of new transmission lines, substations and power plants, says analyst Stow Walker of Cambridge Energy Research Associates. They make wind power -- wildly popular but frustratingly intermittent -- a more reliable resource. And they provide backup power in case of outages, such as the one that hit New York City last week.
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Gar Lipow Posted 4:23 am
18 Jul 2007
The USA today article describes them as costing $2,500 per KW. But the question is: per KW for how long? IF that $2,500 for a ten hours capability, that $250 per kWh of capacity. If it $2,500 for one hour then it is $2,500 per kWh of capacity. I suspect the real figure lies somewhere in that range. Maybe someone with some time can do some more research and come up with a cost per kWh cost. As Rynn says, storage helps stabilize grids. It is useful to all energy sources.
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Kristina & Jason Makansi Posted 5:01 am
18 Jul 2007
In fact, the potential scalability of flow batteries to 100 MW facilities could create a commercial storage option between large-scale bulk (pumped hydro and CAES) and smaller scale distributed systems. Just five years ago, at least two companies (Regenesys-no longer in business and VRB Power Systems) were hard at work blazing this trail. While some of these are in use today, additional demonstration facilities for newer systems have been proposed around the country, but, as with many things in life, getting the job done requires dollars that are often in short supply when it comes to storage.
We see very few prospects for pumped storage because of permitting issues. There hasn't been a pumped storage facility permitted since the early 1980s. The only other "bulk" storage technology ready for primetime is CAES. In a recent post (http://gristmill.grist.org/story/2007/7/7/152836/1112/#6), we discuss CAES and TCAES further.
In terms of other types of storage, there are:
-SMES (superconducting magnetic energy storage) which, although expensive, can be effectively used for grid stability and for preventing voltage sags at manufacturing facilities;
-flywheels are primarily used in the auto and aerospace industry, but are being considered for power delivery in the 500kW range. Flywheel systems are attractive because they are compact and have lower maintenance costs and requirements than battery systems.
-thermal energy storage. This is not a new idea and, in its ice-based form, is already widely used. The other format, using molten salt as the medium, is in development.
As for lead-acid batteries mentioned above, they're attractive because they have relatively high storage efficiency and low capital costs. But these batteries require tender loving care when integrated with power electronics, because they require constant charging to ensure that you use the maximum life of the battery. Lead-acid battery-based storage systems are designed for slow, deep cycle discharges of between 50-80%. Generally speaking, a lead-acid battery has about a 4-year life cycle under normal operating conditions, and because their usefulness is affected by response time, discharge rate, temperature and life cycle costs, their ability to serve broad energy management applications has been limited. (FYI: we strongly support distributed energy and distributed storage systems.)
By the way, a couple of years back we put out an extensive "state-of-the-art" Executive Briefing Report titled, Energy Storage: The Sixth Dimension of the Electricity Value Chain, on the technologies, their applications, and their market potential. We still have a few left over that are available at a steep discount. If you're interested in one, let us know.
Pearl Street/Jason and Kristina Makansi
Learn more and order Lights Out at http://www.jasonmakansi.com/lightsout_endorsements.html
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Jon Rynn Posted 5:03 am
18 Jul 2007
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Jon Rynn Posted 5:13 am
18 Jul 2007
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GreyFlcn Posted 6:48 am
18 Jul 2007
Are all of you STILL slaves to the mentality of electricity as a commodity? Are you lobotomized engineers (yeah, that's redundant!) with no ability for critical thinking?
I'd rather we do coal electricity for our transportation than biofuels/hydrogen.
How long before the batteries go dead and how easy is it to recycle lithium batteries, or any others for that matter? Would we wind up with mountains of toxic dead batteries?
Depends. And Depends. I will say however that from what I've heard not only is it possible to recycle lithium batteries, but people will most often pay you for the extractable lithium resources.
As is, lead acid battery recycling rate is about 98% so battery recycling is not a problem.
As for the battery life that all depends on what type of lithium battery, and how many other batteries you link in parrallel.
Apparently wiring multiple batteries together results in longer overall battery life.
However when the battery is dead for transportation purposes, it's still got 80% of it's charge life left on it.
For a LOT of specs on the nextgen lithium batteries, perhaps you might want to read or listen to this:
http://www.autobloggreen.com/2007/05/07/autobloggreen-qan ...
All in all I've heard of lithium car batteries lasting from anywhere inbetween 10-40 years.
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Kristina & Jason Makansi Posted 7:50 am
18 Jul 2007
Energy Storage Breakthroughs: An evolving technology for managing the grid
Pearl Street/Jason and Kristina Makansi
Learn more and order Lights Out at http://www.jasonmakansi.com/lightsout_endorsements.html
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Colin Wright Posted 3:50 pm
18 Jul 2007
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GreyFlcn Posted 2:51 am
19 Jul 2007
Instead I think G2G will be far more important, since it allows for full control by the utility.
It also doesn't have car consumers wearing down their precious battery life while they can still use it.
And for those car holders, if they sell the battery after it's no use to them. Not only are the utilities getting cheap batteries, but the car consumers are getting a lower cost of ownership.
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CADJOCKEY Posted 7:39 am
26 Jul 2007
Check this technology out. It seems to good to be true
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Gar Lipow Posted 12:58 pm
26 Jul 2007
See: question 11 at
http://www.vrbpower.com/technology/faqs.html.
Yes I know it says "The incremental cost of storage for large systems is approximately $170 per kWh." But I wrote them for clarification, and they told me that in multi-gigawatt sizes that might get them down to $225 or $250, but not below that, and they were not that confident of the $225 or $250 number. VRB is a really great product. And there is tons of stuff it is good for. It can let you replace spinning reserves with operating reserves. It can add reliability to the variable power sources, even without letting them move all the way forward to become baseline sources. It can store small amounts off off-peak power for peaks use. If you read the website you can see other uses. But it is not yet true large scale mass storage in the sense of holding ten hours or so worth of power - nor does it pretend to be.
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amazingdrx Posted 12:20 am
27 Jul 2007
How to move the debate around to storage/conservation now? With an internet enabled grid that stores energy in the form of heating/cooling in everything from your home freezer to the thermal mass of malls.
For instance,cool a mall's floor down (using geothermal cooling that uses a fraction of the energy of air conditioning, that's conservation) during hours with lowest power demand and coast on that cooling for the next 24 hours (that's storage), right through the peak demand time.
Since building heating/cooling produces 36% of our GHG emissions,and large scale wind could provide 95% of our grid power already, this indicates there is more than enough buffering capacity in heating/cooling alone to dispense with other storage.
This is without adding the effect of charging plugin vehicle batteries off peak and doing large scale industrial heating/cooling in such a way as to smooth the grid. Like recycling glass during off peak grid time and using the waste heat to generate power during the peak.
With an internet enabled grid energy use would be timed over the whole grid to make electrical storage of power unecessary. Even in a 100% wind/solar powered grid.
Now how to make industry insiders like the authors of this article realize and incorporate this information about an internet switchable grid into energy policy? Show them it is the bottomline profit path of the future.
Then utilities will race to compete in this area, with customers all connecting their various high energy use heating/cooling devices through switches that are controlled by the smart grid. Eventually plugin vehicles will connect through these switching systems too.
These authors are the ones to convince. But will they interact on revolutionary concepts like this? Hard to say.
http://amazngdrx.blogharbor.com/blog
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