Rhode Island’s Pascoag Utility District turns to batteries to avoid a transmission upgrade

The Pascoag Utility District in Rhode Island plans to use an energy storage project as an alternative to upgrading transmission lines.

The 3-megawatt (MW), 9-megawatt hour (MWh) lithium-ion battery array is being developed by Agilitas Energy, which is beginning the pre-construction phase of the project. The battery system is expected to enter service in the second quarter of 2022.

Pascoag Utility District is contracting for all the battery system’s capacity, both storage and generation. The contract also includes a sharing arrangement on the lowering of the public power utility’s capacity and transmission costs, which vary depending on the utility’s load at times of peak demand on the ISO-New England system.

The batteries will cycle on Pascoag Utility District’s system, charging and discharging and shifting load between peak and off-peak periods and will provide peak shaving services to the utility and ancillary services to ISO-New England.

“The battery storage system will allow us to modernize our infrastructure and avoid the more costly re-construction of existing transmission lines,” Mike Kirkwood, general manager of Pascoag Utility District, said in a statement. “The battery energy storage systems help fulfill our goal to control costs while we assure reliable power.”

The battery storage project was attractive to the Pascoag Utility District because the utility was starting to reach the thermal limits on its existing connection to the grid. The project “avoids $6 million to $12 million in costs that would have been needed to completely rebuild the two National Grid 5-mile, 13.8-kilovolt (kV) feeder lines that connect us to the outside world,” Kirkwood said via email. “Some work is still needed on those lines, but much less than was initially anticipated because of our substation work and the battery project.”

National Grid’s system impact study put “the cost of rebuilding the transmission lines at $6 million with a confidence level of -50%/+200%, meaning the actual costs could have escalated to twice the original estimate,” Kirkwood said. “We had to rebuild our substation no matter what alternative we chose,” he said, “so the battery part of the project is helping us avoid the $6-12 million in the complete rebuilding of the lines.”

Pascoag Utility District is paying about $200,000 in interconnection costs associated with the storage project with funds from a grant allocated by the Rhode Island Office of Energy Resources for unique energy efficiency projects.

Pascoag Utility District qualified for the grant because the battery project, together with the work it is doing on the substation connecting the utility’s system to the New England grid, qualifies as a non-wires alternative. The utility also received $1.4 million in financing for the substation project through Rhode Island’s Efficient Building Funds program, which allowed Pascoag Utility District to receive low cost financing from the Rhode Island Infrastructure Bank, a quasi-state agency that finances public infrastructure.

“The operation of this system will obviate the need for adding costly transmission infrastructure and create a win-win for all parties including Pascoag’s customers,” Barrett Bilotta, president of Agilitas Energy, said in a statement.

Last year, then-Governor Gina Raimondo signed an executive order that committed Rhode Island to meeting 100 percent of its electricity demand with renewable and non-fossil fuel resources by 2030. Many energy experts see energy storage playing a key role in that transition with its ability to store electricity generated by renewable energy resources and discharge it at times when demand is high or renewable resources are not available.

The American Public Power Association offers a Public Power Energy Storage Tracker for association members that summarizes energy storage projects undertaken by members that are currently online.