Nuclear-powered attack submarines are a critical part of the U.S. Navy’s defense armada. Providing docking facilities and essential support for that fleet is the job of Naval Submarine Base New London in Groton, Connecticut, which has piers that can accommodate 11 submarines and employs more than 9,500 naval and civilian personnel working on 687 acres along the Thames River.

Making sure Submarine Base New London has a resilient power supply is a Department of Defense (DOD) priority.

Connecticut Municipal Electric Energy Cooperative (CMEEC), an affiliate NRECA member with offices in Norwich, Connecticut, is part of an innovative microgrid project working to strengthen the naval installation’s energy resiliency while also providing benefits to the co-op’s municipal utility members.

“Resiliency is a big part of this,” says Michael Rall, CMEEC director for asset management. “We were also looking to green up our energy portfolio, and the Navy was looking to green up their base installations.”

The Navy is leasing land on the military installation to host a 7.4-MW natural gas fuel cell project that will supply power to CMEEC while also providing electricity to the base’s microgrid during power disruptions. Microgrids are connected to the larger grid but can function independently if circumstances warrant.

The fuel cell project originated in a DOD review that highlighted the potential for “a single point of failure” in the base’s reliance on Groton Utilities, a CMEEC member, to supply power. Although the base has natural gas turbines and diesel generators with manual switching, the Pentagon viewed the setup as insufficient.

“When that happened, we started exploring different things we could do to help address that,” Rall says.

The co-op and the base considered adding 8 MW of backup diesel generation. But in addition to being a cleaner source of energy, Rall notes, the fuel cells will generate power 24/7 instead of only in emergency situations.

A unique co-op

CMEEC is a unique co-op, formed to supply power to its six Connecticut municipal utility members through purchase and generation. It became operational in 1978 and has since expanded operations to include accounting, financial, and consulting services for its members through a staff of 35 employees.

“We’re here for them, whatever they need,” says interim CEO Michael Lane about the cooperative’s relationship with its municipal members. “We just need to continue to grow and be nimble and be ready for the changes in technology that are coming down the pike.”

The New London Submarine Base project is an example of that approach.

The two 3.7-MW natural gas fuel cells are being installed by FuelCell Energy out of Danbury, Connecticut. CMEEC will connect them to an existing substation. The co-op will have access to the power they generate under a 20-year power purchase agreement. The units are expected to be operational early next year.

FuelCell Energy is one of just three major manufacturers of fuel cells, which use an electrochemical reaction that combines natural gas, a hydrogen-rich fuel, with oxygen to generate electricity. The only waste byproducts are water and heat.

The microgrid portion of the project is being supported financially by a grant from the state of Connecticut. The state backing was spurred by a 2005 Defense Department recommendation that the base be closed following a review of its facilities.

Following Hurricane Irene in 2011 and a severe winter storm in October that left 800,000 people in Connecticut without power, a state assessment also recommended microgrids as a way to increase the resiliency of the overall grid. In 2012, Connecticut passed a law creating a state grant program to support the design and engineering of microgrids at critical facilities. CMEEC was awarded a $5.2 million grant under the program.

The New London project includes Schweitzer Engineering Laboratories’ Real Time Automation controller. The system “will sense an outage on the incoming line, the fuel cells will ramp up, and then there’s automated sequencing for which loads get picked up depending on what generation is available because there is some additional generation on the base as well,” Rall says.

Submarines docked at the piers require 1 MW of power each, he adds, which makes the ability to maintain power essential to operations. The project is part of a larger DOD effort.

“A top priority [is] to ensure that our military capabilities and our ability to protect our nation’s interests are assured through the delivery of reliable and resilient power,” said Lucian Niemeyer, assistant secretary of defense for energy, installations and environment, at a U.S. House Armed Services Committee hearing last year.

The Defense Department’s focus “will include the continued development of distributed energy sources which can be used to power critical missions regardless of the condition of the commercial grid.”

Niemeyer noted that energy is the Pentagon’s single largest operating cost at its bases—in 2017, the DOD spent $3.5 billion to heat, cool, and provide power to installations—and the military is looking for ways to cut its energy bill through improved efficiency and other measures.

To that end, Jan Ahlen, NRECA director for energy solutions, notes that in addition to greater resilience, “the military installations are really pushing for self-sufficiency.” Electric co-ops, he says, are well positioned to help the military with that push because of their growing involvement and experience with microgrids.

“When it comes to microgrids, co-ops are looking at them for a variety of use cases. They’re not just using it for backup power or resiliency. They’re also looking at them for demand response and peak shaving,” Ahlen says. “They’re really trying to get multiple values out of each microgrid.”

Advances in communication and automation have helped to make that possible.

“The key with microgrids is having a microgrid controller that is able to communicate with the utility system and dispatch energy resources when needed, and that technology has improved,” Ahlen says, but he adds that there’s room for further improvement to make the process seamless.

‘A pretty bright future’

CMEEC is not the only co-op working with microgrids for the military. Kaua‘i Island Utility Cooperative, based in Lihue, is involved in a project with the Pacific Missile Range Facility, a U.S. Navy installation, that will house a 19-MW solar facility and a 70-MWh battery storage system on land leased from the base.

Much like the New London Submarine Base effort, the Kaua‘i solar-storage project will help the military facility power essential components on its microgrid in the event of a disruption to power. The solar-storage project also will help the co-op reach its aggressive goal of using 70 percent renewable energy by 2030.

Other electric co-ops are also expanding their involvement with microgrids. North Carolina’s Electric Membership Corporation (EMC), a G&T based in Raleigh, has worked with distribution co-ops on two microgrids that are bolstering their systems while serving as test beds of research.

The microgrids operated by Carolina Electric with Tideland EMC, based in Pantego, and South River EMC in Fayetteville integrate components that include solar panels, battery storage, biogas generation, diesel generators, and water heater controls.

Cordova Electric Cooperative in the isolated Alaskan community of Cordova is increasing its existing microgrid’s capabilities as it tests additional storage through financial and technical support from the Department of Energy and other partners.

Ralls says CMEEC expects greater involvement in microgrids and distributed generation projects.

“I think we’ll see more end-use customers of our utilities looking to do something to increase resiliency and green up their portfolio,” he says. “So we’ll see a lot of customers asking for one-off microgrid projects.”

Ahlen believes microgrids will continue to become more popular throughout the country, particularly where critical infrastructure and resilience is a high priority, whether to maintain essential operations or because the area is prone to severe weather.

We will probably see locations where multiple microgrids are interconnected, Ahlen adds, a “honeycomb model” that allows the system to provide backup power to each other if needed.

“We see a pretty bright future for microgrids.”