Electrifying Public Transit: Scale Microgrids Building Renewable Energy Microgrid for Santa Clara Valley Transit Authority

A renewable energy microgrid is poised to power nearly three dozen electric buses for the Santa Clara Valley Transit Authority (VTA).

Located in the heart of California’s Silicon Valley, the Cerone Microgrid project is expected to save VTA more than $1.2 million annually on energy costs.

Scale Microgrids, a distributed energy company and microgrid developer that was recently acquired by EQT, began construction on the solar and energy storage project at the VTA’s Cerone Bus Depot in San Jose last month.

The system will include 500 kW of solar canopies, 4 MWh of battery storage capacity and 3 MW of electric vehicle fleet chargers.

Buses will charge overnight to minimize energy costs and ensure availability for their morning routes.

"By integrating on-site solar and battery storage, our microgrid will help VTA serve the region's public transit needs while reducing their electricity costs by over a third," Neil Maguire, chief technology officer at Scale Microgrids, said in a statement.

PG&E to upgrade infrastructure

The VTA expects to take delivery of 35 battery electric buses in 2026. While the microgrid will supply much of the energy required to charge the fleet, the facility will not operate off grid.

To meet VTA’s increasing demand, Pacific Gas & Electric (PG&E) is upgrading its utility infrastructure and adding 3 MW of additional capacity.

“This is the kind of collaboration that moves clean energy forward,” said Jeremy Howard, senior regional manager at PG&E. “By supporting EV charging infrastructure, we’re helping VTA build flexibility and resiliency into their operations.”

Making progress on California’s zero-emissions bus mandate

The microgrid and pending EV bus delivery bring the VTA one step closer to satisfying California’s mandate that all public transit agencies transition to 100% zero-emission bus fleets by 2040.

“Expanding our zero-emission bus fleet reflects my priority to modernize VTA’s operations while improving air quality and reliability for the communities we serve,” said Sergio Lopez, VTA’s board chair.

Lopez, who is also mayor of Campbell, a city of roughly 43,000 people southwest of San Jose, added, “It also advances our commitment to equity. These new buses will serve eastern and central San Jose—areas with high transit use and historically high pollution.”

Resilience, even during grid outages

The microgrid’s onsite solar generation and energy storage systems will ensure the VTA’s electric fleet is able to operate and serve the community, even when the grid is stressed or there are outages.

VTA will also have the option to connect a temporary generator for additional backup power during extended outages, according to Scale.

Supporting the future of public transit

Cerone Microgrid was designed with the future growth in mind. The switchgear and microgrid controls can scale as VTA’s electric fleet grows.

VTA is also working with Lehigh University’s Institute of Cyber Physical Infrastructure to optimize its electric fleet rollout.

“Our researchers and students have been working alongside VTA to develop ways to use local energy storage and solar generation, schedule bus charging, implement routes, assign bus operators and coordinate with the main grid," said Shalinee Kishore, Iacocca Chair and professor of electrical and computer engineering, and director of Lehigh's Center for Advancing Community Electrification Solutions.

The Santa Clara Valley Transit Authority is not alone in its desire to scale sustainable, electric public transit.

On the other side of the country, the Brookville Smart Energy Bus Depot microgrid in Maryland, which came online in 2022, is perhaps one of the nation's best known public transit microgrids.

The 6.5-MW microgrid in Montgomery County was built by AlphaStruxure, a joint venture of Schneider Electric and the Carlyle Group, a global private equity firm.

The installation can accommodate 70 electric buses and includes 1.6 MW of solar photovoltaic canopies, 3 MW of battery energy storage, renewable natural gas-ready on-site generation and more than 4.14 MW of charging capacity.

In 2024, AlphaStuxure began construction on a solar, energy storage and hydrogen microgrid at Montgomery County’s David F. Bone Equipment Maintenance and Transit Operation Center in Rockville, Maryland.

That installation will include 5 MW of solar and 2 MW/7.4-MWh of battery storage, part of which will charge electric buses. A 1-MW electrolyzer will create carbon-free hydrogen for fuel cell buses.

From Grid to Garage: Smarter Energy Systems for EV-Ready Dealerships

Oct. 23 EnergyTech Webinar with Schneider Electric and Sprocket Power