A Proterra 40-foot Catalyst XR (extended range) electric bus drove 258 miles (415 miles) on a single charge under test conditions at Michelin’s Laurens Proving Grounds (LPG). The Catalyst XR configuration for the max mileage test used 8 NMC Li-ion battery packs, with a total energy capacity of 257 kWh. Average speed was 30 mph (48 km/h); average energy consumption was 0.8 kWh/mile.

Proterra offers both extended-range (XR) and fast-charge (FC) versions of its electric bus, using different battery technologies. (Earlier post.)

Proterra’s TerraVolt FC fast charge battery options (lithium titanate, LTO chemistry) allows for maximum run time with minimum dwell time. This system can be recharged on-route in less than ten minutes with a 500kW charge rate. Fast charge configured buses can also be charged in-depot to take advantage of off-peak charging times. Proterra has demonstrated that this option can travel more than 700 miles in 24-hour period. Proterra’s fast charge vehicle uses a 100 kWh pack.

The new Catalyst XR Extended Range product uses an NMC higher energy density pack, said Horton, allowing flexibility in the deployment of electric buses on routes of all types. The XR is compatible with the fast charging equipment (although the charge will not be as quick as with the FC); full charge recovery can be accomplished in less than 90 minutes.

Based on the new test results, Proterra predicts its ten pack XR configuration (321 kWh) will achieve 300 miles (483 km) on a single charge. According to available General Transit Feed Specification (GTFS) data, typical urban and rural bus routes in the United States run less than 200 miles a day, bringing most routes within reach of Proterra’s current technology.

Beyond meeting a given route’s minimum range requirements, Proterra electric vehicles are poised to make a significant impact on the transit market because of the Catalyst’s low operational cost per mile compared to diesel, CNG, and diesel-hybrid buses. Over the 12-year life of a bus, Proterra customers will reduce maintenance costs, saving around $135K.