American electric bus manufacturer Proterra introduced its new high-power charging solutions this week at the American Public Transportation Association (APTA). The three new solutions were introduced under Proterra’s Power Control Systems line. They range from 60 kW to 500 kW, opening up new use cases for fleet operators around the world.
A fleet of buses charging at night represents both a significant electrical draw on the grid and a large source of energy storage. Just take a look at the image above and imagine 20 … 50 … 100 electric buses with ~400 kWh of storage on board all charging at 125 kW to get an idea of the early scale bus depots will be working with.
It was with that in mind that Proterra built vehicle-to-grid (V2G) capability into its new chargers, which allow them to not only pull power from the grid to charge the bus, but to also feed power back into the grid, if needed. Taking the 100 x 400 kWh buses in the example above, that fleet has the potential to be used as a 40 MWh battery for the transit operator, city, or electrical grid to draw from as they see fit, opening up new potential sources of revenue for fleet operators, disaster response for cities and first responders — to name just a few possibilities.
Importantly, all of Proterra’s new solutions were designed to be compatible with the J1772 CCS plug-in charging standard and the emerging J3105 inverted and roof-mounted overhead charging standard. Building standards-based charging into its chargers and its buses give fleet operators confidence that investments in hard-wired charging stations and buses will last far into the future and not be obsoleted based on changes to the fleet in the future.
“With vehicle agnostic charging, we have peace of mind that our electric bus fleet infrastructure investments are future-proof,” said David Carr, Facilities and Fleet Manager at RTC Washoe in Reno, Nevada. “Scalable, interoperable charging infrastructure supports our long-term mission to sustainably serve Reno and our neighbors, by providing innovative and cost-saving solutions that ensure clean, reliable transit today and for years to come.”
Building on the hardware standardization, Proterra’s new chargers also take advantage of standardized communications protocols, using the Open Charge Point Protocol (OCPP), version 1.6. Much like a hardware standard, the OCPP standard provides for a common language that enables the chargers to speak in a hardware-agnostic language with other chargers, central network servers, and dashboards.
The new offerings also add pantograph-style charging options. They represent the de-facto standard for overhead transit bus charging. These are most commonly implemented with high-speed chargers installed along routes to allow for opportunity charging on-route or at bus depots. The new overhead chargers were designed in collaboration with industry-leading Schunk Carbon Technology.
“We’re thrilled to collaborate with Proterra and bring large-scale fleet charging for electric vehicles to market in North America. We’ve had strong traction in Europe to date equipping the largest electric bus fleet with our roof charging pantograph technology,” said Robert Averkamp President Schunk Carbon Technology US.
Ultimately, the new family of chargers introduced by Proterra this week reinforce its commitment to leveraging industry-standard charging protocols and communication protocols to enable fleet operators to migrate legacy fleets to electric vehicles without having to worry about being locked into a proprietary charging standard that might not work with future purchases.
“As more fleets embark on 100 percent electrification, we’re committed to providing a seamless transition that leverages open and universal standards and empowers our customers to effectively scale with confidence,” said Ryan Popple, Proterra CEO. “By leveraging common charging standards for electric buses, the transit industry will avoid vendor lock-in and de-risk infrastructure investments, ultimately accelerating mass adoption of EVs.”