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New Hampshire may soon become part of the home-battery experiment, as Liberty Utilities is nearing approval on a plan to help 250 of their customers install the systems, with hundreds more open to participation by other companies.

“It’s amazing to see a small utility in a small state put forward a proposal like this that’s really innovative,” said Christopher Rauscher, director of policy for Sunrun, which plans to offer batteries to homeowners if the program is approved by the state. “Two or three years ago, under the best-case scenario we would not have thought we would be here.”

Under the plan, which will be discussed Dec. 29 by the Public Utilities Commission, 100 residential customers would be eligible to buy two Tesla Powerwall batteries from Liberty Utilities at a reduced cost, and another 150 would be eligible if the first phase is successful.

“It is a pilot program. We’re testing how it works, how customers like it,” said John Shore, Liberty Utilities spokesman. If all goes well, he said, the utility might expand the project down the road.

The batteries will be able to provide electricity during power outages, replacing or augmenting generators. They can also trim a home’s electric bills by taking advantage of special time-of-use rates that Liberty wants to create, filling up with cheap electricity at night and releasing it during the daytime when rates are higher.

Cutting peak costs

Utilities, which have to buy power on the wholesale market in order to provide it to customers, are fans of batteries because they can reduce the amount of electricity the utility must obtain during peak periods such as hot summer afternoons when power is very expensive.

The cost of those peak purchases gets magnified through what are known as demand charges, which means that cutting peaks by even a little can save a lot of money. Those savings are spread out among all a utility’s customers, including those that don’t have batteries. A similar residential battery program in Vermont is run by Green Mountain Power, which says it has saved hundreds of thousands of dollars by reducing demand charges.

In the second phase of the proposed project, up to 500 Liberty residential customers will be able to participate using batteries bought via other companies, such as Sunrun and ReVision Energy. This “bring your own battery” angle is important because the initial proposal called for batteries only from Liberty Utilities, leading to opposition from companies who feared it would help the utility squeeze out future competition. Neither Sunrun nor ReVision is opposing the new plan.

“ReVision certainly applauds Liberty Utilities for trying to get something done here. We think that battery storage is an important and growing opportunity for New Hampshire residents to help reduce utility costs,” said James Hasselbeck, director of operations for the New England firm.

Sunrun and ReVision will couple their battery offers with solar panels, which means that in extended power outages the batteries can be recharged during the day. Liberty Utilities will not require solar to be part of the equation and expects many of the customers taking up the offer will not have solar panels.

Two Powerwalls combined

Liberty Utilities’ program will require each homeowner to get two Tesla Powerwalls, which the company says is a requirement from Tesla.

They can be bought up front for $2,433 per battery, or paid off at $50 per month for both batteries over 10 years. Cost details have not been released by Sunrun and ReVision.

The program would create three different electricity rates. The most expensive period would run from 3 p.m. to 8 p.m. on weekdays and the cheapest from 8 p.m. to 8 a.m. weekdays, with a mid-range in between. Weekends and holidays would see only the two less expensive rates, each covering 12 hours. The Public Utilities Commission will decide on the actual rates.

Liberty Utilities will control the batteries, which will have separate meters from the main household power meter, filling them up and discharging them to maximize cost reduction.

“One of the key things we need to learn in the (pilot) is to be able to predict when our peaks are, so we can dispatch these batteries at the correct time,” said Shore.

Massachusetts, Rhode Island and New York have, or are putting into effect, “bring your own battery” programs for homes. Green Mountain Power’s project only uses batteries owned by the Vermont utility.

In New Hampshire, Liberty Utilities provides electricity to about 43,000 customers in 20 towns, mostly around Lebanon and in the southern Merrimack Valley, with none in the Concord region. Its electric service area is different than the area where it provides natural gas, which includes Concord.

A major weakness of electricity has always been that even though it is easy to transmit, it is very difficult to store. This has meant power plants and power lines must be built so that all the power that everybody needs can be generated and transmitted at any given moment, which is expensive.

The rise of lithium-ion batteries has changed the equation, making it feasible for the first time to store electricity.

This has put storage on the front line of the push to redesign the entire power grid. Huge banks of batteries are being built, several thousand kilowatts at a time, and programs being developed to encourage businesses and residences to obtain batteries, all to help utilities deal with the complexities of intermittent renewable energy from wind and solar as we transition away from fossil fuel generation.

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