Battery Seen as Way to Cut Heat-Related Power Losses

By DIANE CARDWELL

Published: July 16, 2013

http://www.nytimes.com/2013/07/17/business/energy-environment/battery-seen-as-way-to-cut-heat-related-power-losses.html?src=rechp&_r=0

As scorching weather envelops the Northeast and the Midwest, electric utilities are scrambling to keep the power on while air-conditioners strain utilities' capacity. By Tuesday afternoon in New York City and Westchester County, for instance, Consolidated Edison had logged nearly 7,700 interruptions since the heat arrived on Sunday, and it had dispatched crews to restore almost all of the power.

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Eos Energy Storage

The Eos Energy System battery is about half the size of a refrigerator. Several utilities in the United States and abroad plan to test it for storage of electricity for times when it is needed most.

Such disruptions have plagued utilities for years: how do they keep extra electricity on hand and ready to go, avoiding the need to cut the voltage in stressed neighborhoods and lowering the risk of blackouts?

Now, several utilities, including Con Edison, National Grid and the large European utilities Enel and GDF SUEZ, have signed up to fine-tune and test what they hope could lead to an answer — a battery half the size of a refrigerator from Eos Energy Storage, the company said Tuesday. If the testing goes well, the batteries hold the promise of providing storage that until now has been unaffordable on a large scale.

"Energy storage is no longer an idea and a theory — it's actually a practical reality," said Steve Hellman, Eos's president. "You're seeing a lot of commercial activity in the energy storage sector."

Part of the appeal is economic: utilities could buy power from centralized plants during off-peak hours, when it is cheaper, and use it to feed the grid at peak hours when it is typically more expensive. That could also relieve congestion on some transmission lines, reducing strain and the need to spend money upgrading or repairing them. In addition, batteries could help integrate more renewable sources like solar and wind into the power grid, smoothing out their intermittent production.

"Energy storage in general has been kind of a holy grail for utilities — a lot of the generation and demand is instantaneous," said Joseph Carbonara, project manager in research and development at Con Edison, who is managing the Eos program. "The utilities have always been looking to buffer that."

Utilities and institutions across the country, many with grants from federal or state energy departments, are testing energy storage technologies. Con Edison and the City University of New York are using a different zinc-based battery from Urban Electric Power to help reduce the school's peak energy use as part of a New York State Energy Research and Development Authority program. In California, Pacific Gas and Electric is studying sodium-sulfur batteries that can store more than six hours of energy. And Duke Energy is working with lead acid batteries from Xtreme Power that are linked to a wind farm in Texas.

At the same time, there are a host of start-ups racing to develop different technologies for a wide range of applications, and already there are some large-scale batteries tied to the grid. But the technology has generally proved too expensive for widespread adoption.

Eos says it has gotten around that problem. Its battery relies on zinc, a relatively plentiful and cheap element. The company projects that its cost will be $160 a kilowatt-hour, and that it would provide electricity cheaper than a new gas power plant built to help fulfill periods of high demand, Eos executives said. Other battery technologies can range from $400 to about $1,000 a kilowatt-hour.

"They've got a cost factor that makes it economically viable to use their batteries," said Troy DeVries, director of research and development at Con Edison. He added that the batteries did not contain toxic chemicals, making them more appealing for use in a congested city like New York.

In recent years, utilities have had to find creative ways to contend with surging demand during heat waves. Con Edison, for instance, has used generators to support electric substations and, from its central command station, has shut off central air-conditioning units in thousands of homes and businesses. The utility has even canceled Little League night games in Staten Island to save the energy that the field lights would use.

The battery project is still in its early stages, with the company collaborating with each utility to complete its prototypes with an aim of having some up and running next year.

Eos plans to work with the utilities to test small-scale versions of the batteries and how they connect to different power grid systems. The eventual goal would be to develop a battery the size of a cargo container for use on a commercial scale.

Testing on a small scale is necessary, said Michael Oster, the Eos chief executive, because the companies are trying to sell a new technology to a traditionally conservative industry.

"We're getting that industry involved early — we're understanding their pain and understanding their needs and getting them comfortable with the technology," Mr. Oster said. "They need it badly enough that they're willing to take the risks but also to join in mitigating those risks with others."

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