NSTAR Electric Company d/b/a Eversource Energy (NYSE:ES) on Nov. 30 filed with the Massachusetts Department of Public Utilities a petition for exemption from the Town of Oak Bluffs Zoning Bylaws in connection with the company’s proposed construction and operation of an energy storage system (ESS) totaling 14.7 MW at the company’s Oak Bluffs Service Center in the Town of Oak Bluffs.
The company said that it requests that, to the extent possible, the department issue an order on the petition within nine months from the date of filing in order for the company to maintain its projected construction schedule and in-service dates for the project.
The ESS would be built in two phases, with Phase 1 to be 4.9 MW and Phase 2 planned to add 9.8 MW. Both phases would include a battery storage system; a power conversion system (PCS); a control and protection system; step-up transformers; switchgear; heating, ventilation and air conditioning (HVAC) chillers and other system components. The company added that most of those components would be located in a two-story, Cape Cod-style building at the site. Additionally, there would be a 10-foot acoustically treated sound wall to be designed in consultation with Oak Bluffs officials.
Construction of Phase 1 is expected to begin in the late winter or early spring of 2020, and be completed by the end of 2020. The company added that the estimated cost of Phase 1, based on a planning grade estimate of +/-25%, is $15m. Construction of Phase 2 is expected to begin in the spring or summer of 2022, and be completed by the summer of 2023. The company also said that the estimated cost of Phase 2, based on a planning grade estimate of +/-25%, is $28m. Thus, the total project cost is estimated to be about $43m (+/-25%), the company noted.
The project would use lithium-ion battery technology, which was determined to be the most suitable energy storage technology for the project based on cost, technological maturity, and suitability to help meet the electric needs on Martha’s Vineyard. Lithium-ion batteries typically achieve >90% round-trip efficiency – discharge/charge cycle – making them well suited for energy applications, and they can support the ramping requirements – power/time – of all use-cases identified for the Martha’s Vineyard ESS, the company added.
The company said that the zoning bylaw does not allow the construction and operation of public utility uses, such as the ESS, as-of-right on the site. Moreover, the construction and operation of the proposed ESS requires relief from certain dimensional provisions of the zoning bylaw. Thus, the company added, Eversource is seeking zoning exemptions from the department to allow for the construction of the project.
In addition to the individual exemptions, the company also requested a comprehensive exemption from the operation of the zoning bylaw, with respect to its proposed facility. The company added that the department has recognized that comprehensive zoning relief is appropriate in circumstances where, as in this case, numerous individual exemptions are required, and the issuance of a blanket exemption could avoid substantial public harm by serving to prevent delay in the construction and operation of the proposed use.
The company noted that in January 2017, it submitted testimony describing plans for its Grid Modernization Base Commitment (GMBC), which, in part, described the company’s intent to invest in and implement ESS demonstration projects in Massachusetts, generally, and on Martha’s Vineyard, specifically.
Martha’s Vineyard is an island that relies on local generation during various electricity demand conditions and as a back-up to electricity supplied from the mainland by four undersea cables. At the same time, the company added, Martha’s Vineyard has limited capacity to accommodate additional distributed energy resources (DER), such as wind or solar generation, due to difficulties in managing voltage stability, with a high ratio of generation to load.
With the current level of DER integration, it is costly to interconnect incremental DER because significant additional distribution upgrades become necessary, the company said.
Eversource said that adding energy storage, with other improvements, will allow it to frequently utilize the ESS in place of the aging diesel generators on the island.
As a result, the company added, the ESS will reduce greenhouse gas emissions associated with the generator operation and defer other distribution investments, while enhancing system reliability on Martha’s Vineyard, and creating opportunities to integrate additional DER.