PROVINCETOWN — For the first time in years, the Outer Cape managed to avoid major power outages last winter. There were storms — including on Dec. 23, when several East End streets were flooded with salt water, and on Feb. 4, when frozen pipes burst all over town — but they were not exacerbated by a loss of power that would have disabled sump pumps and heating systems as well.
Perhaps fortune favors the prepared, because this was the first winter that Eversource had a dedicated battery installation at 90 Race Point Road ready to step into any power gaps. There were no such outages, however. The 25-megawatt, 38-megawatt-hour lithium-ion Battery Energy Storage System —a.k.a. the BESS —is a tool that has yet to be used.
Housed in the town’s transfer station north of Route 6, the large-scale microgrid system is designed to provide immediate backup power to the roughly 11,000 Eversource customers along circuit 96, the single 13-mile power line that runs from the Wellfleet substation to Provincetown. Depending on the time of year and the location of the damage to the aboveground line, Eversource estimates that the BESS can keep the lights on for up to 10 hours while repair crews are deployed. During heavy load periods — i.e., the summer months — the BESS could support two to three hours of demand.
“This really is a unique solution to a historic issue that we’ve dealt with on the Outer Cape,” said Eversource spokesperson Chris McKinnon. “When called upon to deploy and provide backup for a certain duration, it’s going to greatly benefit our customers,” he said.
The Outer Cape’s geography makes it a challenge for utility providers. Strong winds from the Atlantic create extreme weather. The multiday storms that damage electric lines also make it too dangerous for technicians to mount their bucket trucks and repair the damage — so outages can last for days.
Eversource first proposed the BESS as a resilience concept to the Mass. Dept. of Public Utilities in 2017. A redundant underground line, which is common practice for minimizing outages, was also considered, but would have involved extensive and costly permitting through the National Seashore. Putting a second line underground would have also required an additional 115,000-volt line from Orleans to Wellfleet.
Not having to build these two additional cables resulted in “significant cost savings that more than paid for the project,” said John Ventura, Eversource’s manager of distribution system engineering for southeastern Massachusetts.
The BESS is composed of nearly 10,000 individual battery modules, Ventura said. In this way, the microgrid is “designed with built-in resilience,” so that issues with a handful of modules will not deactivate the entire battery, he added.
When not in use, the battery system remains charged and connected to the energy grid. If the 13-mile overhead line is damaged, the system is designed to identify the location of the damage and restore power to disconnected customers within a minute.
The DPU initially approved a budget range of $35-45 million; the final cost was $49 million. Provincetown Town Manager Alex Morse confirmed via email that the town did not foot any bills for the project and that Eversource reimbursed all third-party review costs.
Initially, the battery was planned for the Wellfleet power station, but a final feasibility analysis found that situating the battery “as close to the tip of Provincetown as possible” would optimize its effectiveness. At the April 2019 town meeting, Provincetown voters unanimously approved a lease for Eversource to operate at the transfer station.
Construction began in 2019 and was completed last year. Testing ran through the fall and concluded in December, when the battery was officially commissioned. Eversource used a series of short overnight outages to confirm that the battery engaged when needed.
“The way this facility is designed is that you really don’t know when it’s working,” said state Sen. Julian Cyr.
Martha’s Vineyard, also in Cyr’s district, was the planned site for a second battery storage project, but Eversource so far has stuck with a traditional cable approach for the Islands. “I think [the BESS] is going to remain the first of its kind for a while,” Cyr said.
Cyr said that he got “an earful about the power going on and off periodically” in the fall but hasn’t heard complaints from constituents since. Cyr and state Rep. Sarah Peake were recently on a call with Eversource about a different issue when they realized that the power miraculously hadn’t gone out all winter. “We were remarking to ourselves, hey, is this because of the battery?” said Cyr.
It was not. According to McKinnon, there were 11 reported outages in Provincetown between Sept. 1 and March 1, but none were along the main distribution line, so the battery did not deploy. A small outage along a side street does not engage the BESS; the system responds only to major outages along the main line.
The battery itself caused a very brief outage, however. On Wednesday. April 5, a malfunction caused a one-minute outage while the BESS was being restored to full service after being taken offline for maintenance.
“Our team is looking at the settings on a specific piece of automated equipment on the electric system to determine why it briefly malfunctioned,” McKinnon said.
The BESS is a pilot project for Eversource, and it has significance beyond the Outer Cape. Energy storage is an important aspect of the global switch to renewable sources such as solar and wind energy, which by their nature are not constant. Being able to capture excess energy in the daytime and release it during evening hours, for instance, is a requirement if renewable energy is to fully displace carbon-intensive fuels like natural gas.
The data from BESS will help inform future energy storage projects, Ventura said. He has made presentations at national conferences on the project. “It’s something we’re proud of,” Ventura said.