Developers are planning to build a bus maintenance and operations center in Maryland that they say will be the nation’s largest renewable energy-powered transit depot in terms of capacity. The faciliity in the Montgomery County suburb of Washington, D.C. would also feature a microgrid and be the East Coast's first transit depot to have green hydrogen production, with an onsite electrolyzer powered by a solar array and battery storage.

County officials plan to initially power 13 fuel cell electric buses at the Equipment Maintenance and Transit Operation Center in Rockville, but the facility will be able to accommodate up to 200 mixed-fleet vehicles, according to AlphaStruxure, the company leading the project for the county. 

Juan Macias, CEO of AlphaStruxure, says the facility will include 5 MW of rooftop and canopy solar generation, 2 MW and 7.35 MWh of battery storage and 4.5 MW of charging capacity. The microgrid would also power five buildings to be constructed at the site. The electrolyzer could produce 131 kg of hydrogen daily, according to Calvin Jones, who heads county fleet management services. 

AlphaStruxure, which estimates the facility will cut carbon dioxide emissions by 4,000 metric tons per year, plans to use its digital platform to manage microgrid operations and performance.  "This will really be, I believe, the gold standard for resilient sustainable public transit,” Macias says. 

The effort is part of Maryland's push for clean energy under the new administration of Gov. Wes Moore, which in March raised its goal for offshore wind energy to 8.5 MW from about 2 GW by 2031.  “As a former transportation engineer, I know that comprehensive transportation projects are those that are equitable, accessible, and help us meet our climate goals,” said Lt. Gov. Aruna Miller. “The clean energy bus depot in Montgomery County checks all those boxes and will ... to make Maryland a leader in transportation access and clean energy technology.”

Schneider Electric and Carlyle Group JV

Boston-based AlphaStruxure is an energy-as-a-service joint venture of Schneider Electric and equity investor The Carlyle Group Inc. The company has a public-private partnership agreement with the county to design, build, finance and maintain the facility. The county will pay AlphaStruxure a fixed commodity rate over 25 years with performance guarantees, according to County Executive Marc Elrich. A spokesperson for AlphaStruxure declined to share expected project costs. 

Construction is set to start later this year and county officials expect the facility will begin operating in 2025. Macias says the developers have selected a construction team, but have not yet finalized the contracts and declined to name contractors. 

AlphaStruxure says the facility, which will use onsite solar generation and green hydrogen production to power buses, is the first of its kind on the East Coast. A similar project was built by the SunLine Transit Agency in California’s Coachella Valley between 2017 and 2020. That facility can produce 900 kg of hydrogen to power 17 fuel cell buses, according to a California Air Resources Board report, but does not have its own onsite power generation. The Champaign-Urbana Mass Transit District in Illinois also uses its own electrolyzer to power fuel cell buses, but relies on offsite solar. 

Brookville_depot_ENRweb.jpgAlphaStruxure completed another bus depot with onsite solar for Montgomery County last year.
Image courtesy of AlphaStruxure


County officials have set a goal to cut carbon emissions from public transportation by 80% by 2027 and reach zero carbon emissions by 2035, according to Elrich. He said this facility would advance that goal, while also delivering resilience during storms and power outages. It is designed to be able to run indefinitely in “island mode” with solar power and battery storage. Macias says the plan also calls for existing backup generators to be retained in case of an emergency.

AlphaStruxure has installed more than 350 microgrids in the U.S., according to Schneider Electric CEO Annette Clayton. 

Montgomery County previously worked with AlphaStruxure for its Brookville bus depot in Silver Spring, which features a 6.5-MW microgrid with onsite solar for charging electric buses. That facility, also delivered via a public-private arrangement, opened last fall and officials plan to have 70 electric buses based there by 2026. 

“We believe through experience that solving our energy challenges really comes down to three things: electrifying, digitizing and decarbonizing,” Clayton says. “Microgrids are key to achieving all three.”

California's Santa Clara Valley Transportation Authority also is building a 1.5-MW solar energy microgrid to power its bus fleet, working with developers Proterra and Scale Microgrid Solutions, which is set to include hydrogen as more vehicles using that fuel source are added to the fleet, according to a report in Power magazine.