The Journey to Making Bus Exportable Power Systems a Reality

By Matt Smith, P.E., and Jacob George | 8/4/2023

THE FEDERAL TRANSIT Administration has a vision to transform public transit buses into emergency electric power backup sources during major power disruptions. This will take advantage of electric power that is stored in the batteries of new-energy buses and direct these “mobile power sources” to public buildings to enhance resiliency in critical situations. This approach could be vital for powering emergency shelters, command centers and other operations housed in small buildings, tent communities or similar.

blueprint of bus exportable power system

In 2013, FTA commissioned a project to investigate whether this concept, also known as Bus Exportable Power Systems (BEPS), was feasible. The study determined that the concept was not only feasible but could be very useful in emergency situations since buses are mobile and can be purposed to serve when and where most needed. This would also lead the way to exploiting secondary uses of a growing fleet of green-energy buses (electric, fuel cell, hybrid, etc.).

As a recommendation of the original study, a key next step was to establish standards for extracting power from a bus and providing it to a building. These standards will enable stakeholders such as manufacturers, transit authorities, communities and emergency management organizations to move forward in developing plans and leveraging resources to tap this potential. Consistent standards will also allow stakeholders and owners/operators of the facilities to work together to rapidly repurpose buildings or power microgrids to enhance resiliency.

With funding allocated by Congress for the development of national standards for BEPS, FTA selected a team led by Inventev (an EV technology start-up in Detroit, MI) and further comprised of SAE International, Proterra, Next Energy, Kimley-Horn and The Engineering Shop. This team is charged with documenting and demonstrating the standard(s) that would enable the export of power from a bus.

In this current effort, a power converter (inverter) will be external to the vehicle; however, there is a future vision of enabling the power export with a system integrated on a bus. The objective is to adapt or incorporate as many existing documented vehicle and building electrical standards as possible and integrate them into a singular approach to enable BEPS. The project will also create a guidebook for local authorities to plan and execute the export of power using the BEPS system.

The project is well under way, with the design of the inverter and the integration of all the devices that are needed to make the BEPS vision a reality. Said Dave Stenson, Inventev founder and CEO, “We are excited to lead this effort with the FTA and have found substantial public- and private-sector interest from transit authorities, communities and manufacturers to advance the technology.”

The next exciting step is to demonstrate that the concept works using real facilities. At least two separate demonstrations are being planned for mid-2024. These are envisioned to use two different new-energy technology buses: a battery-electric bus (BEB) from Proterra and a fuel-cell bus (FCB) from New Flyer. The BEB demonstration is planned to take place under the auspices of the Alexandria Transit Company (DASH), Alexandria, VA; and the FCB demonstration is planned to take place in Flint, MI, with the Mass Transit Authority (MTA).

Both these forward-looking agencies are committed to exploring the potential for rollout of the BEPS technology and working with local emergency management personnel to plan the use of export power in critical situations. Ed Benning, CEO of MTA, said, “We at Flint MTA are excited by these new green technologies, which are flexible and provide a variety of different uses to our residents in Flint and Genesee County, including this use case where our buses can be mobile backup energy sources.” Added Raymond Mui, the chief infrastructure and development officer of DASH, “As one of the leaders in converting a public transit fleet to battery electric, we believe that the benefits of battery-electric buses do not end at the tailpipe. We are eager to demonstrate their additional value as a source for backup energy and part of the solution for emergency management.”

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Part of FTA’s goal for this effort is to broaden general industry awareness of BEPS, with the aim that bus manufacturers, transit agencies and emergency management stakeholders will be able to leverage the project outcomes. For further information on the BEPS project, visit and/or sign up for updates on the project at or scan this QR code.