Microgrids - Solar

Nation’s largest microgrid transit depot breaks ground in Maryland

Nation’s largest microgrid transit depot breaks ground in Maryland
The David F. Bone Equipment Maintenance & Transit Operation Center (EMTOC) in Montgomery County, MD (courtesy: AlphaStruxure)

Today AlphaStruxure, an Energy as a Service (EaaS) microgrid solutions provider, and Montgomery County, Maryland broke ground in Gaithersburg on an integrated microgrid infrastructure project featuring electric bus charging and on-site green hydrogen production powered by solar and battery energy storage.

Once completed, the David F. Bone Equipment Maintenance and Transit Operations Center (EMTOC) will be the largest renewable energy-powered transit depot in the United States. It will also be the biggest transit depot microgrid and the first on the East Coast to produce green hydrogen on-site, per AlphaStruxure.

The about 7.5-MW microgrid project is expected to be built by the fall of 2025. It will ultimately consist of solar arrays, electric bus chargers, battery energy storage, and a county-owned hydrogen electrolyzer, allowing the depot to operate in “island mode” indefinitely.

A rendering of the EMTOC microgrid, expected to be completed by fall, 2025 (courtesy: AlphaStruxure)

“It’s a joyous moment to be breaking ground on a project that represents the new standard for public transit in the United States,” said Juan Macias, CEO of AlphaStruxure. “The county has proven itself as a national leader in zero-emissions transit in part by prioritizing simultaneous procurement of both the buses and the sustainable infrastructure needed to power them. Both are fundamental to a successful fleet transition. Our Energy as a Service approach enables the County to achieve sustainable and resilient transit — without upfront capital, in a way that de-risks the financial, construction, and operations phases of the project.”

Montgomery County operates the second-largest bus fleet in the Washington, D.C. region. Its David F. Bone Equipment Maintenance and Transit Operations Center is a major depot within Ride-On Montgomery’s network and the fifth largest county-owned energy consumer.

By 2035, the depot is projected to accommodate 200 zero-emissions buses; about 150 are expected to be hydrogen fuel cell electric buses (FCEBs), starting with an initial wave of 13 FCEBs by late 2026.

“We’ve realized that a lot of the block runs, the routes that we run with our buses, are longer than what some of the electric buses at this time can manage,” explains Michael Yambrach of Montgomery County’s Office of Energy and Sustainability.

He says a modern 600 KW battery-powered electric bus is limited to a range of around 100-125 miles.

“So we’re moving some of those, replacing some of those diesel busses that can do those longer routes with hydrogen buses, and we will be making green hydrogen at our facility to be able to support those buses,” he continues.

Yambrach says electric buses run at about 31 cents per mile; diesel buses are about 85 cents. “So from the county standpoint, the ability to reduce fuel costs in running its fleet is substantial,” he concludes.

“We are kind of proofing ourselves against technology right now that we’re not betting on all-electric or all-hydrogen, and we’re balancing that fleet between the two types of technologies that exist right now.”

A rendering of the EMTOC bus depot, which will eventually be home to dozens of hydrogen fuel cell buses (courtesy: AlphaStruxure)

This microgrid follows the launch of the Brookville Smart Energy Bus Depot in 2022, which was the County’s first fully constructed microgrid-powered bus depot and also led by AlphaStruxure. Together, the two depots will eventually power about 335 zero-emissions transit buses, according to the County’s latest fleet transition plan.

Like the Brookville depot, this existing site will remain fully operational throughout its 28-phase construction process, with no impact on transit services. The microgrid will provide sustainable, resilient power to a mixed fleet of battery electric and hydrogen fuel cell electric buses (FCEBs), along with the facility’s five buildings. It will also be interconnected to the Pepco utility and is engineered to operate in island mode indefinitely, ensuring uninterrupted service for the County’s constituents during extended grid or power outages and emergency situations. Specifically, it will include:

  • 5.65 MWDC of rooftop and canopy solar generation
  • 2 MW/7.44 MWh battery energy storage
  • Up to 2.25 MW of charging capacity
  • 1 MW hydrogen electrolyzer
  • Software tools and IoT-connected hardware
  • A complete overview can be found here.

In addition to powering on-site production of green hydrogen, a resilient fuel source for FCEBs, the microgrid will also be able to send up to 2 MW of renewable energy back to the utility grid via a Pepco net metering program.

AlphaStruxure, a joint venture of Carlyle and Schneider Electric, is delivering the microgrid to Montogomery County without requiring capital expenditures via an EaaS contract, a long-term agreement ensuring predictable operating expenses, performance, and energy pricing. The Boston, MA-based company will deliver all aspects of design, construction, and long-term operations and maintenance.

AlphaStruxure’s partners for this project include Mortenson for design-build; Schneider Electric for the battery energy storage system, microgrid controls, switchgear, and services; WSP as the engineer of record; AZZO for network and cybersecurity; The Mobility House for charge management software; and Heliox for EV charger hardware. Trillium is providing the hydrogen electrolyzer system directly to the County.

“We’re seeing load growth like we’ve never seen in decades in the U.S., going from an estimated 2500 terawatt hours to by 2035, potentially 4200 terawatt hours,” added AlphaStruxure’s Macias. “As all these entities are acquiring these vehicles and driving this energy transition, I think Montgomery County stands alone in really thinking about the energy infrastructure that has to be put in place within the context of everything that’s going on around and not only thinking about it, but taking action.”

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