Transit agencies are putting solar panels on bus depots to charge electric buses, and paying for them in 2 different ways

How transit agencies use solar power to charge electric buses

Solar panels on bus depots are how a growing number of transit agencies use solar power to charge electric buses. At least 4 United States transit agencies, in Montgomery County, Maryland, Santa Clara County, California, Austin, Texas, and Anaheim, California, have each built or are building one. Some own the panels outright. Others sign a contract that lets a private company build and own the panels instead, paying for the power over many years rather than upfront, under a deal called energy as a service or a power purchase agreement.

The largest project pays nothing upfront

The newest bus depot in Montgomery County pairs 5.65 megawatts of solar panels with a 2 megawatt, 6.88 megawatt hour battery that stores solar power for buses charging at night, according to the joint groundbreaking announcement from the county and AlphaStruxure, the company building and owning the system. The depot also gets a 1 megawatt hydrogen electrolyzer, a machine that uses spare solar electricity to split water into hydrogen fuel and store it, the same announcement states. The county pays nothing upfront, and the depot is expected to run 200 zero emission buses by 2035, part of 335 buses planned across 2 depots in the county.

This project is the largest renewable energy powered transit depot and transit depot microgrid in the nation.

Marc Elrich, Montgomery County executive, speaking at the groundbreaking for the newest depot. Source 1.

An earlier depot in the same county proved the model first

Montgomery County already tested this approach once. Brookville, an earlier and smaller depot in the same county, opened on November 1, 2022 with 1.6 megawatts of solar panels, a 3 megawatt battery and 1.8 megawatt gas fired backup generators, making a 6.5 megawatt microgrid, according to Canary Media. The county paid nothing upfront, and Brookville was built to run 70 electric buses by 2026.

Austin and Anaheim chose 2 more financing paths

CapMetro, the transit agency in Austin, Texas, is paying its own money instead of signing a service contract, 34 million dollars, funded locally, for a 12 acre canopy of more than 7,000 solar panels over its North Operations bus yard, according to HOLT Renewables, the company building it. Construction started in October 2023, and the canopy is meant to support more than 200 zero emission buses that charge through pantograph chargers, arms that lower from an overhead structure onto a bus roof to charge it fast between routes.

This revolutionary project represents one of the largest deployments of pantograph bus chargers in North America.

David Carr, director of zero emission vehicles at CapMetro. Source 4.

Anaheim Transportation Network took a third path, a 20 year power purchase agreement with bp pulse and REC Solar, who built and still own a 514 kilowatt solar canopy and sell the agency its power. The canopy is stated to cover 25% of total expected energy use and is projected to save 4.8 million dollars in fuel costs over 20 years, according to a joint statement from the 3 companies. The agency runs 80 battery electric buses from the site.

The pattern is about depots, not passenger stations

None of the 5 projects examined puts solar panels at a passenger station. Every one sits at a bus depot or a maintenance yard, where buses charge overnight or between routes. For other agencies weighing the same move, the finding is not whether to add solar power, but which of the 2 payment models fits the budget, own the array and its upfront cost, or pay a service contract over time instead.