Floating solar power at the Fort

A new floating solar power project at North Carolina's Fort Bragg is helping the military advance towards its goal of being more energy independent.

By Paul MacDonald

This past November, the largest floating solar power project in the U.S. southeast started operations in North Carolina, and is now helping the U.S. military advance towards its goal of being more energy independent—and more sustainable.
 
The innovative project is part of a major energy service contract the U.S. Army signed with Duke Energy and Ameresco, for its massive Fort Bragg military base in North Carolina.

The 1.1-megawatt floating solar facility now operating at the base is part of a $36 million contract that focused on energy resilience and security at Fort Bragg, including infrastructure modernization, lighting and water fixture upgrades, heating, ventilation and air-conditioning, and boiler system improvements.  
 
The floating solar part of the project also includes a Tesla 2MW/2 megawatt-hour battery energy storage
system.

“Duke Energy’s work with Fort Bragg will lead to better energy efficiency and cost savings at the base,” said Brian Savoy, Duke Energy’s chief strategy and commercial officer. He added that this project helps put Fort Bragg at the forefront of renewable energy innovation, with the unique floating solar facility.
 
The floating solar system was built on the Big Muddy Lake located at Camp Mackall, at the base. Fort Bragg will own and operate the solar system.
 
“With this system, the largest floating solar array in the Southeast, we will be able to provide energy resiliency to Fort Bragg operations through sustainable resources,” said Col. Scott Pence, who was garrison commander for Fort Bragg when the project was announced.
 
“With this partnership, Fort Bragg not only has renewable electricity, but energy security that will be critical with continuing the installation’s mission during a power outage.” 
 
The project fulfills the commitment made in the Army Climate Strategy to increase resilience while delivering clean energy and reducing greenhouse gas emissions, added Rachel Jacobson, assistant secretary of the Army for installations, energy and environment. “When we collaborate with local utilities and industry to promote energy resilience while powering the local grid, it is a winning solution across the board,” she said.
 
The U.S. Army has an overall climate strategy goal of using 100 percent carbon-free electricity by 2030.

Most of the actual work for the Fort Bragg floating solar project was done on land. The array was built on the shore of Big Muddy Lake, and pushed out on to the surface of the lake. The 1.1 MW facility is now the largest floating solar power project in the U.S. southeast.

The floating solar project is certainly high profile within the U.S. military. Fort Bragg has 50,000 active duty personnel, and has the largest population of any U.S. military installation, with more than 270,000 people working and living within its boundaries.

Among the many essential organizations at Fort Bragg, the installation is the home headquarters for U.S. Army Forces Command and U.S. Army Special Operations Command.

The installation is also home to the Joint Special Operations Command, the Army’s XVIII Airborne Corps, and the headquarters of U.S. Army Reserve Command.

There are two airfields located within the confines of the installation: Pope Army Airfield and Simmons Army Airfield.

Fort Bragg is a key military facility, being what the military terms a premier projection platform, with one of the most strategic airfields within the Department of Defense, supporting the Immediate Response Force, the National Mission Force and other locally assigned units.

The U.S. Army and U.S. Air Force can deploy worldwide within 18 hours of notification, from Pope Army Airfield.

Now helping to support all this with renewable energy, Ameresco, in partnership with Duke Energy, has built a 1.1 MW floating solar photovoltaic system on the Big Muddy Lake at Camp Mackall, a remote Special Forces training site at the base.

Under the design-build contract, Duke secures third-party financing to fund construction, and the U.S. Army pays down the financing annually with the utility savings that the project generates over the term of the contract. Those savings are important, as the U.S. military is Duke Energy’s largest customer in North Carolina, paying the utility some $40 million a year.

Even though the Fort Bragg base area is extensive, most of the land is dedicated to training purposes.

Utilizing approximately two acres of water on the lake, the innovative floating solar array enables power for this remote training site, without a requirement for land use. The on-site Tesla battery energy storage system will provide seamless transition to on-site generation during utility provider outages.

Audrey Oxendine, Fort Bragg Energy and Utilities Branch Chief, explained that they had been working on developing a Utility Energy Services Contract (UESC) for the base for several years, and decided to include a floating solar component in the contract.

A floating solar project addressed a few challenges on the base. Even though the base area is extensive, most of the land is dedicated to training purposes.

“We did not want to do traditional ground-mounted solar because we have a limited amount of land,” she said.

The woods around Camp Mackall are also home to endangered red cockaded woodpeckers. They would have had to clear seven acres of land for a one-acre solar farm, so the trees wouldn’t shade out the
solar panels.

The floating solar project utilizes only 2.3 acres of Big Muddy Lake, which is 60 acres in size.

“It really only occupies a small portion of the surface area of the lake,” said Oxendine. The project is not expected to have any negative environmental impacts on the lake.
 
In the past, Camp Mackall has also been subject to power outages, she noted.

“We have been working with Duke Energy to try to improve the energy situation there because we only have one feed coming into the substation serving Camp Mackall.”

Solar power is not new to the U.S. military, Duke Energy or North Carolina. North Carolina is fourth in the nation for overall solar power capacity. Duke Energy owns and operates more than 40 solar facilities in North Carolina—one of which is a 13-MW facility at the Marine Corps Base Camp Lejeune in Onslow County.

Helping to support Fort Bragg with renewable energy, Ameresco, in partnership with Duke Energy, has built the floating solar photovoltaic system on the Big Muddy Lake at Camp Mackall, a remote Special Forces training site at the base.

The difference with this solar project, Oxendine noted, is, of course, that it is floating. “Everyone involved needed to become familiar with the floating solar concept, and implementing the project,” she said.

In carrying out the project, the base had the help of the U.S. Army Corps of Engineers, who facilitate such energy contracts. “The Corps has engineers who supported the base in reviewing the details of the contract, and the technology, to make sure the savings and the calculations were accurate—to make sure the project will work,” said Oxendine.

Actually building the project was Florida-based D3 Energy, a market leader in floating solar. The company has an exclusive focus on floating solar systems, and is said to have built the most floating PV systems in the U.S.

D3 says it has expertise in all areas of floating PV from early-stage development and engineering to installation, service, and maintenance.  

The company’s floating PV projects have been a wide variety of sizes and types, from megawatt-plus systems to microgrids to creative marketing pieces. It has engineered and developed projects all over the world including New Zealand’s first ever floating solar array, and for major entities such as Florida Power & Light, Orlando Utilities, Comcast, and the City of Orlando—and now, Fort Bragg.

D3 has an exclusive manufacturing partner, Ciel & Terre, which says it is a pioneer in floating photovoltaic solutions. Ciel & Terre has been developing large-scale floating solar projects worldwide since 2011 and is recognized as a leader of the floating PV market due to the development of their patented technology, Hydrelio, which was used on the Fort Bragg project.
 
Ciel & Terre says it has over 700 megawatts of power connected across 250 projects installed in 30 different countries. Oxendine explained that most of the actual work for the floating solar project was done on land. “The array was built on the shore of the lake, and pushed out on to the surface of the lake, almost like a boat,” she explained. The Ciel & Terre system includes walkways, which can be used to check on the array, once it is on the water. Besides the Ciel & Terre components, the project also has LG solar panels and SMA Sunny Highpower PEAK3 inverters.

	Florida-based D3 Energy, a market leader in floating solar, actually constructed the Fort Bragg project. D3 has an exclusive manufacturing partner, Ciel & Terre, which says it is a pioneer in floating photovoltaic solutions. Ciel & Terre has its own patented technology, Hydrelio, which was used on the Fort Bragg project. The Ciel & Terre system includes walkways (above), which can be used to check on the array, once it is on the water.

Because the work was carried out on the base, security clearances were required for all the workers building the project. The contractors involved supplied employee names to the base, which then carried out clearance checks. Any material related to the project that was being transported to the base was also subject to security checks.

There were some minor COVID-related supply chain delays in getting material for parts of the overall UESC project, such as LED lights, but these were easily managed.

From start to finish, the floating solar project took about 90 days to build. “They started in August, and finished just before November,” said Oxendine.

“We were fortunate in that we did not have any hurricanes or severe weather that impacted the project.”

Big Muddy is a fairly calm lake, but this area of North Carolina has its share of hurricanes. The floating solar project is rated for Category 5 hurricanes. It is anchored both to the shoreline, and the bottom of the lake itself.

“It rises and floats with the level of the lake,” says Oxendine. “There is enough slack in the tether to the anchor so it can rise and fall with the lake level.”

It looks like the future for floating solar could be, pardon the pun, extremely bright. Floating solar is expected to grow quickly over the next decade. The National Renewable Energy Laboratory (NREL) says that if even a portion of the most suitable reservoirs in the U.S. were covered, floating solar could generate almost 10 percent of U.S. electricity.

And since the project’s completion, Oxendine has fielded inquiries from a number of individuals and groups interested in hearing how floating solar power works at Fort Bragg. North Carolina State University is working with the North Carolina Aquarium at Fort Fisher to evaluate the feasibility of an innovative floating solar plus energy storage installation to improve both the sustainability and the resiliency of the aquarium. A proposed solar installation would float on top of a pond located behind the Fort Fisher Aquarium, taking advantage of under-utilized land while allowing for cooling of the solar panels, which would improve efficiency.
 
“With floating solar, it does not have to be a lake—it can be any type of water body,” noted
Oxendine. “I think it has a lot of further potential for the military, too. We have some other projects where it is the same type of situation as Camp Mackall, where we don’t want to utilize training land for solar, but we have some lakes nearby that could support floating solar.”

Q1 2023