Why transit agencies put microgrids at their own bus garages for backup power
Two public transit agencies just finished separate projects that show why transit agencies put microgrids at their own bus garages for backup power. A microgrid is a small power system, solar panels, batteries or other on site generation, plus the buildings and vehicles it serves, that can disconnect from the main utility grid and keep running on its own power, a mode the United States Department of Energy calls island mode. New Jersey Transit and Montgomery County, Maryland, picked their own bus depots for the same 2 reasons. A depot already carries a large and growing electrical load from buses charging at once, and losing power at a depot strands riders rather than inconveniencing 1 building.
New Jersey Transit protects 7 facilities after Superstorm Sandy
Superstorm Sandy cut power across the New Jersey Transit system in 2012, the agency says in its own account of why the project began. In response, the agency is building TransitGrid, on site power at 7 facilities, 3 bus garages, 3 rail stations and 1 ferry terminal, so each keeps running if utility power fails. The Federal Transit Administration granted 45,828,737 dollars toward the first phase, matched with 15,276,246 dollars from the New Jersey Transit Trust Fund, for a Phase 1 total of 61,104,983 dollars. The agency states 409,764,814 dollars is allocated to the entire project. Burns Engineering, the firm that worked on the project, says it partnered with Sandia National Laboratories to study how the microgrid affects traction power, the electricity that actually moves the trains, along with signals and other critical train systems inside the project boundary.
This funding will move NJ TRANSIT toward self sufficiency in the event of a disaster such as Superstorm Sandy where commercial power systems may be limited or unavailable.
Kevin Corbett, New Jersey Transit executive director. Source 1.
New Jersey Transit names 7 facilities under Phase 1, Greenville, Wayne and Meadowlands bus garages, Newark Penn Station, Broad Street Station and Secaucus Junction Station, and Port Imperial Ferry Terminal. The count by type above is this draft own tally of that list, all from source 1.
Show the numbers
| Bus garages | 3 |
| Rail stations | 3 |
| Ferry terminals | 1 |
Montgomery County finished a 6.8 megawatt microgrid built around bus charging
In Maryland, Montgomery County finished the David F. Bone Equipment Maintenance and Transit Operations Center, a bus depot known as EMTOC, on April 30, 2026, the county says in its own completion announcement. The site pairs 4.8 megawatts of solar power across 9,800 panels on 16 canopies with a 2 megawatt, 6.9 megawatt hour battery and 2.25 megawatts of bus charging capacity, according to Mortenson, the contractor that built it, for a total microgrid capacity of 6.8 megawatts. Mortenson says a fleet depot works as a microgrid site because it already powers both the buses charging at once and the buildings on the same property, which produces 1 large, predictable, dual purpose electrical load in 1 place rather than 2 separate smaller ones. The completed system can run in island mode indefinitely, disconnected from the grid, the county says, and the Maryland Energy Administration put in 1.6 million dollars toward the project. The depot is planned to run 200 zero emission buses by 2035.
The EMTOC microgrid is built to orchestrate highly variable changes in energy supply and demand.
David Dise, director of the Maryland Department of General Services. Source 2.
Solar generation and battery storage power from source 2. Bus charging capacity from source 4, the contractor figure for the same asset, used in place of the 2.375 megawatt figure the county states, per the research file conflict resolution.
Show the numbers
| Solar generation | 4.8 |
| Battery storage power | 2 |
| Bus charging capacity | 2.25 |
The same reasoning, 2 different scales
Neither project puts a microgrid at a depot because panels happened to fit the roof. Both point to the same mechanism, a bus depot already needs a large and predictable amount of power, already has room for on site generation and storage, and already matters enough to riders that losing it during an outage costs more than 1 building going dark. For a public agency weighing where to place a resilience investment, that is the case for choosing a depot over a passenger station or an office building.