Maximizing Grid Energy Storage in Nantucket

This article was originally published on PNNL on Oct. 9, 2019.

NANTUCKET, Mass. –  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.

With support from OE and National Grid, the PNNL team created a sophisticated distribution system network model for Nantucket island to accurately assess a full portfolio of energy storage-enabled use cases. These include outage mitigation; Volt-VAR optimization and conservation voltage reduction programs; frequency regulation; spinning reserves; and forward capacity market participation. PNNL also found that the BESS and generator could reduce the duration of outages experienced by Nantucket residents by nearly half. To read the full report, click here.

“This is a groundbreaking study that greatly expands our ability to accurately estimate grid impacts and financial implications of grid energy storage investments,” said Patrick Balducci, chief economist at PNNL who led the assessment. “The results of this research effort will be used to build a more resilient, reliable, flexible and cost-effective electricity system on Nantucket Island. It also provides a road map and measuring stick for grid energy storage projects across the United States.”

Balducci said the study incorporates several innovative elements and approaches that together paint a much more complete picture of the value energy storage can bring to grid operators and consumers.

“This study highlights a valuable storage project and could also be used to make a strong case to regulators to allow a rate-based asset to participate in energy markets,” Balducci said. “The key is understanding how grid energy storage investments will perform under realistic grid operating conditions using real-world use cases and factoring in market dynamics.”

About PNNL

Pacific Northwest National Laboratory draws on signature capabilities in chemistry, Earth sciences, and data analytics to advance scientific discovery and create solutions to the nation’s toughest challenges in energy resiliency and national security. Founded in 1965, PNNL is operated by Battelle for the U.S. Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit PNNL’s News Center. Follow us on FacebookLinkedIn, and Twitter.

About National Grid

National Grid (LSE: NG; NYSE: NGG) is an electricity, natural gas, and clean energy delivery company serving more than 20 million people through our networks in New York, Massachusetts, and Rhode Island. National Grid is the largest distributor of natural gas in the Northeast. National Grid also operates the systems that deliver gas and electricity across Great Britain.

National Grid is transforming our electricity and natural gas networks with smarter, cleaner, and more resilient energy solutions to meet the goal of reducing greenhouse gas emissions by 80 percent by 2050. Our Northeast 80×50 Pathway is an industry-leading analysis for how to reach that goal in the states National Grid serves, focusing on the power generation, heat, and transportation sectors.

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