Martha’s Vineyard Transit Authority (VTA) has teamed up with Arup to launch a microgrid that uses on-site solar power and battery energy storage for the agency’s growing fleet of electric buses.

Located at VTA’s existing depot in Edgartown, the microgrid supports a more reliable and environmentally responsible public transportation network for Martha’s Vineyard Island, off the coast of Massachusetts.

The single-user microgrid, designed by Arup, PXiSE, and Vermont Energy Investment Corporation, includes a new 700 kW DC solar PV array, battery energy storage, and a diesel generator as back-up, as well as 16 vehicle charging stations, with 20 more to be added in the coming years. The system can be disconnected from the main grid during power outages to then tap into its own stored electricity and solar-generated power. The system also allows the agency to reduce its demand on the grid during peak hours and enables it to charge vehicles overnight through its energy storage infrastructure without interrupting service.

“Now more than at any time in the past, our focus is on the future, and that future is electric,” said Angie Gompert, the VTA’s Administrator. “Our overriding priority is to provide a fleet that will serve the Island for years to come with buses that are the most reliable, emission-free, fuel-saving vehicles available. In order to do this our infrastructure needs to support and reflect this commitment.”

Seeing the promise of electrifying its bus fleet, in 2018 the VTA began to transition from diesel to battery-electric vehicles to better serve its 17,000 year-round residents who live in six towns connected by the bus service.

The microgrid will establish a resilient independent energy source while significantly reducing carbon emissions. According to the VTA, the electric bus fleet will reportedly eliminate 36,000 tons of carbon dioxide over 10 years of driving 1.4 million miles annually.

The network will also include induction charging stations that recharge the buses on route, allowing them to stay in service for their 200 to 300 miles-a-day circuit without detouring to recharge.

Planned for operation in Fall 2021, the stations are wireless charging plates embedded in the ground at bus stops. The vehicles will drive over the charging stations as passengers board and exit the vehicle, enabling buses to be partially charged numerous times throughout the day at each stop. With on-site battery storage systems to provide energy cost reduction, and emissions free backup power, these charging stations easily blend in with Martha’s Vineyard’s natural landscape.