Island Transitioning To All-Electric Bus Fleet, Microgrids
Martha’s Vineyard is well known as a summer vacation destination for travelers attracted to the Massachusetts community’s beaches, harbors, villages, and scenery. The island’s population can swell to 200,000 or more during the height of the tourist season when normally, the full-time resident population is less than 14,000 people.
Seasonal fluctuations in population have always posed challenges in terms of meeting electricity demand, and those challenges became even greater a few years ago when Martha’s Vineyard Transit Authority (VTA) decided to transition its bus fleet to all-electric.
As PV Magazine reported, the VTA partnered with the Vermont Energy Investment Corporation (VEIC) to make a move to an all-electric bus fleet. The first electric buses were purchased in 2018, and a solar canopy at the charging station started operating three years later.
Photo Courtesy Vineyard Transit
Because of the extra electricity needed to power the bus fleet, Martha’s Vineyard leaders decided to install a microgrid powered by the VTA’s solar photovoltaic (PV) array, which includes battery energy storage.
One advantage of a microgrid is that it gives Martha’s Vineyard an independent source of clean power, meaning it doesn’t have to depend on outside sources that might involve fossil fuels.
According to the Microgrid Knowledge website, another advantage is that it “helps offset the high cost of power” on the island because it generates its own electricity through the solar PV array.
A lot of technology and expertise goes into ensuring the microgrid works properly. To help manage the system, the VRA called on PXiSE Energy Solutions. As part of its work, PXiSE provided a microgrid controller to automate the integration of various energy generation sources, according to PV Magazine. Those sources include a 466-kilowatt solar array, a battery storage system, and 16 bus charging stations.
Photo Courtesy PXiSE Energy Solutions
Microgrid controllers enable charging centers to keep running for several hours in the event of a power outage. PV Magazine reported they can also connect to “virtually any device” on the grid and aggregate power from solar and battery systems, creating a “single virtual power plant” that can operate off the grid.
Another cool feature of the controller is that it can plan 24 hours ahead. As Microgrid Knowledge noted, this means the controller can optimize the “powering up and down of the microgrid’s assets while adjusting for real-time data and running the microgrid autonomously so the VTA doesn’t require specialized staff.”
Maybe the most important aspect of the system is that it is scalable, which means it can grow as the VTA expands and installs more microgrids on the island.
According to Microgrid Knowledge, when additional ones are added, “each will operate independently and primarily remain connected to the main grid.”
Photo Courtesy PXiSE Energy Solutions
Meanwhile, the microgrid system allows the VTA to reduce its demand on the main grid during peak hours. It also lets the agency charge electric buses overnight without interrupting service, according to a 2021 report from the Intelligent Transport website.
The VTA estimates that the all-electric bus fleet will eliminate 36,000 tons of carbon dioxide over the course of a decade.“Now more than at any time in the past, our focus is on the future, and that future is electric,” said Angie Gompert, VTA 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.”
