Utility AEP plans backyard energy storage

CAMBRIDGE, Mass.--Utility company American Electric Power (AEP) plans this year to place equipment in residential areas capable of storing a few hours of electricity, one of the first tests of distributed storage on the power grid.

Ali Nourai, AEP's manager of distributed energy resources, calls the storage program a potential "game changer" for the utility industry. Nourai spoke during a panel on grid energy storage at the MIT Energy Conference here Saturday.

"The key for distributed energy is not because it's cheaper. The key is national security--we don't have a huge storage (device) that can be blown up," Nourai said.

The storage units would be the size of a relatively small "backyard transformer," each wired to provide enough electricity for four to six houses, he said. Together, those storage units could provide back-up power to neighborhoods during outages and potentially for other applications, Nourai said.

"Aggregated, hundreds of these units controlled (by AEP)...effectively do the same as one big storage unit," he said. "It's closer to the load, and it has the potential to (create) competition on price."

AEP is one of the few electric utilities in the U.S. that has already deployed storage on the electricity grid, which is very expensive. The utility, which operates in Midwestern and Southern states, started three years ago with a one megawatt sodium sulfur battery. It now has six megawatts worth of storage in three locations using this technology, Nourai said.

In these cases, AEP can do "peak shaving" in which it draws on the stored electricity during peak times, such as the middle of hot summer day when air conditioning loads are high. Because the stored energy supplies electricity to the grid, the utility doesn't need to pay for electricity at high peak-time rates.

Although this has proved to be a viable application, speakers on the energy storage panel said that the high cost of batteries and other storage technologies makes it difficult for utilities to justify investments in the technology.

Because of the high cost, energy storage devices need to be used for a number of applications to generate sufficient revenue, the speakers said. For example, a large battery could provide back-up power, do peak shaving, and be used to stabilize dips in grid signal frequency.

"At the end of the day, it's going to be cost that drives acceptance of storage on the grid," said Gary Colello, CEO of Premium Power, which makes a zinc bromide fuel cell that provides short-term storage to utilities in the U.S. and Canada.

This is a large megawatt storage device already on AEP's grid. Click on the image to see a photo gallery of power grid storage technologies.

(Credit: AEP)

Another problem is that current utility regulations are structured around utilities making investments in power generation. "Without a fairly radical rethink of utility regulations, to get the mass movement of energy storage beyond a handful of utilities--it's not going to happen," said Matthew Nordan, the president of consulting firm Lux Research.

AEP's Nourai said the regulators need to be educated on the different values that energy storage can provide. Some of those are economic, like providing back-up power, whereas others are societal benefits because they help the environment. For example, storage makes bringing renewable energy sources onto the grid more feasible.

Wind, solar forcing the issue
The growing interest in renewable energy, in fact, is what prompted AEP to explore energy storage in the first place, said Nourai.

"Our business was being threatened by something that everybody loves--renewable power," he said, noting that the amount of solar power from its customers grew from kilowatts to megawatts over the past five years. "We love it, too, but we have no control over it. (Customers with solar) could turn off megawatts of power or not maintain it."

Wind and solar energy are also variable, meaning they can't deliver electricity as reliably as a fossil fuel power plant. Energy storage, through batteries or compressed air storage, is one way to deal with that variability.

To deal with the projected increase of renewable energy, utilities need a "buffer" in the form of storage so that it can control the flow of electricity onto the grid in a managed way, Nourai said.

Although the basic technology for energy storage hasn't changed in decades, interest has peaked substantially in the last few years. Nourai said that five years ago, only engineers went to energy storage conferences; now half of the attendees are venture capitalists and politicians. The energy storage session at the MIT Energy Conference was standing-room only.

For its distributed storage plans, AEP said that just four hours of back-up power could address 90 percent of the outages the utility has to deal with. "When (storage) is closer to the customer, it's more reliable," Nourai said.

[gerrrg]

Energy companies could do that (battery storage at dispersed sites) today to store excess energy produced at night, to offset a lack of production capacity during the day, and ease the load on transmission lines.

[James Anderson Merritt]

Making utility power more reliable is especially important here in California, where it seems as if any extreme natural event (cold, wind, rain) can knock out power in at least one neighborhood for a while -- occasionally tens or hundreds of thousands of customers at a time. I agree that decentralization of the grid, through local generation and storage, is an important and promising direction for us to take. I am a little worried, however, when I read that hundreds or thousands of storage units, scattered around a large service region, would all be "under the control" of the central utility. I worry that sophisticated remote-control mechanisms might defeat the national security goal, by allowing terrorists or even pranksters to disrupt service in many different localities at the push of a button. (Of course malefactors have been exposed to this idea through a subplot in this season of "24." We don't have the excuse that "nobody ever imagined this could happen!") At least, there should always be a local override.

Has anybody heard from EESTor in Texas, lately? When they made their announcement of a cheap, rapid-recharge/rapid-discharge, high-capacity electric storage (ultracapacitor) unit that could be drained and replenished as long as the unit remained intact, most coverage focused on the potential applications in the transportation industry (e.g., power storage to maximize range and performance for pure Electric Vehicles). But a potentially more widespread application for such units would be in household or neighborhood storage. If EEStor doesn't deliver, or its product disappoints, what would be the most cost-effective alternative storage method?

[RideMan]

Interesting comment in the article: "...current utility regulations are structured around utilities making investments in power generation." I was not aware of that, but it seems like it would be a pretty easy fix: regulations SHOULD be structured around utilities providing adequate power and maximizing availability and reliability. On-grid storage allows for micro-generation by customers and can virtually eliminate outages. Sounds like a win-win to me if the costs can be managed.

[dbargen]

Ok, for you consumers out there, are you REALLY willing to personally spend score of 1000s of dollars up front to change from the cheap abundant, local source that is coal (the US is literally the Saudi Arabia of coal) to acres upon acres of land comitted to undependable solar panels and wind turbines?

There's a damn good reason the almost 100% subsidized "alternative" energy sources account for less than 6% of our nation's power generation: They're by no means cost effective to what we have now, and nearly un-marketable to people with common sense.

If your area has problems with brownouts, thank you local eco-friends and state gov't. for blocking development of further grid support, be it coal or nuclear. Anyone still have "China Syndome?"

[finleyd]

Actually, while these storage systems are touted as promoting renewble energy, they could be of greater assistance in helping "baseload" power sources like coal or especially nuclear, by providing "peak power".

[thinkerer]

The economic argument that coal is cheaper than "subsidized" alternative sources is only partially correct. Coal and other fossil fuels have deep and historic subsidies built into their price structure in the form of tax relief, cheap (or no-cost) mineral-rights acquisition, and other long-standing perks that distort the price picture considerably (and are occasionally the basis for arguments to subsidize newer energy types).

[thinkerer]

I concur with the idea of using these to maintain power during "natural events" - there are many areas that suffer intermittent power outages and storage units would be great replacements/supplements for internal-combustion emergency generators. I would hope that this would push the development of something other than traditional chemical storage cells which are costly, messy and require frequent maintenance or replacement.

As far as the security issues go, I should think that the lessons learned from the deregulation of the California power markets have had some impact; the system is much more open to exploitation and abuse from within its own corporate structure than from some mythical villain from the outside.

[afterhours]

While this article rightly concentrates on generation and storage, the other side of the equation (use and conservation) remain important for the overall goal of conserving. Unless the overall goal isn't conservation, but selling the product (electricity). It galls me that my Windows XP systems STILL do not have automate energy savings features like scheduled shutdown built into the system. This would seem to be an easy patch to add in along with the next Tuesday release of bug fixes and the antiviral crap we contend with every time MS releases yet another patch. The Macintosh systems we've added to our network have this built into the OS, so we'll be adding more Macs for our Word/Excel needs. No auto shutdown feature in Windows Vista Business version, either. I don't want these systems on for the 16+ hours they are not in use. They aren't as likely to have directory corruption from an unexpected power outage while no one is around to manage them if they are already shut down (really hard to mess up a hard drive with the computer OFF), they can't be part of a spambot network (at least while they are off - and yes, we use protection), and they don't spin my meter when they are off like they do when they are hibernating or fully on. Microsoft has to be one of the largest backward-thinking companies out there. Such a simple tweak to the system, so lame they don't offer it. I'm migrating away from them.

[Dr_Zinj]

Power companies own the entire energy system in the United States today. They own production, distribution, and storage; and have a near total lockout of other competitors in any area. They were granted this by laws, regulations, and rules due to the national necessity of providing this in an uninterrupted manner.

California brown outs, New Orleans Katrina disaster, the latest 2008 New England Ice Storm, and my several 1 minute outages this weekend all illustrate that power companies are stretched to the limit and infrastructure is on the brink of catastrophic failure.

The rules need to be changed to encourage a far greater percentage of privately owned, low volume, distributed production and storage. The power companies need to plan for a future where they are the distributors and remaining demand providers; and not the sole primary producers and storers.

[TV James]

Considering the high winds in my area and the general unreliableness of Puget Sound Energy, I would totally give up some space in my backyard for a small power storage unit for my neighborhood, and/or one or several of aerovironment's tiny wind turbines.

[BillWright510]

One thing that bothers me about this article is the units used for energy storage. Quoting from above: "with a one megawatt sodium sulfur battery. It now has six megawatts worth of storage in three locations using this technology." Watts are a unit of power, not of energy, which is what you want to store. Apparently these storage units can provide a megawatt (or six megawatts) of power, but for how long? Without that bit of information, you don't know much about the storage. A AAA battery can provide a megawatt of power if it could discharge all its energy quickly enough. The unit of energy storage are watt-hours, not watts.

[mlamonica]

The megawatt-size storage units discussed on this panel are being used for short bursts of energy - on the order of minutes and hours. During the panel, the representative from AEP talked about the megawatt capacity, not the megawatt-hours. If you want more detail on power output from the NAS batteries, you can see this release.
http://www.aep.com/newsroom/newsreleases/?id=790

[jk70]

Superconducting Magnetic Energy Storage System "SMES" offer lots of potential when combined with wind and solar.

[mrpoopoo]

Did Nourai mention what kind of batteries would be used for this application? Small sodium sulfur batteries are not commonly considered economical since they have to be kept at elevated temperatures north of 350 degrees C and thus have significant parasitic load.

[gubatron]

We should use solar cells and electrolysis to fill up underground hydrogen tanks. When peak times come, we convert the hydrogen energy intro electricity with home use fuel cells. That way we could store a lot more energy per home.