National Grid and PNNL Collaborate to Capture Full Value of Grid Energy Storage

Source: Nick Hennen, PNNL, October 9, 2019

With the simple cutting of a ribbon this week, residents of Nantucket Island, joined by state and local officials and representatives from National Grid, the U.S Department of Energy’s Office of Electricity (OE), and Pacific Northwest National Laboratory (PNNL), ushered in a new era of energy resiliency and efficiency on the island. 

Located 30 miles off the southern coast of Cape Cod, Nantucket Island is home to about 10,000 year-round residents. In the summer, the population swells to about 50,000 as people flock to the island’s wide, sandy beaches and agreeable climate, significantly increasing electricity demand.

National Grid, energy provider to more than 20 million people in the northeastern United States, supplies electricity to the island via two undersea transmission lines and two small, aging generators located on the island. Analyses have shown that if one of those undersea transmission lines failed, electricity demand on Nantucket Island would likely exceed the grid’s capacity to meet those needs.

To meet the island’s growing energy needs, National Grid developed an integrated plan, called “IslandReady,” to upgrade the island’s electricity infrastructure. Central to the plan was the installation of a 6-megawatt (MW) Battery Energy Storage System (BESS) with 48 megawatt hours (MWhs) of capacity, along with a new combustion generator unit with a maximum capacity of 16 MW. The BESS, built by Tesla, is the largest of its kind in New England.

“DOE’s Office of Electricity has funded analytical studies, performed by the national laboratories, to validate energy storage business cases for projects from Alaska to New Mexico and from Washington state to Massachusetts,” said Imre Gyuk, director of OE’s Energy Storage Program. “These studies have provided substantial returns to evaluate a portfolio of applications using various storage technologies. The Nantucket Project is a great example of OE and the national labs collaborating with industry to advance these efforts.”

“We knew the grid energy storage facility and new backup generator would defer the need for a third undersea transmission line, which would have been very expensive,” said Rudy Wynter, president and COO of National Grid’s Wholesale Networks. “But once we made the decision to invest in the energy storage system, we asked PNNL to help us figure out what else we can do with this investment to create additional value for our customers.”

The answer turned out to be quite a lot. PNNL’s study, in addition to confirming the significant benefits expected over the life of the project through deferral of the third undersea transmission line, identifies substantial potential benefits by also using the system to support local grid and market operations.

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