One of the biggest limitations of electric buses is range. Now, though, a US company has eked out over 250 miles (402 km) from one of its electric buses. The Proterra Catalyst XR is said to afford the best efficiency rating ever for a 40-ft (12-m) transit bus, at 22 mpg (12.8 l/l00 km) equivalent.
Electric buses are already in use in, or due to roll out to, a number of major cities around the world, including Gothenburg and London. Despite this, the technology is still relatively embryonic and so continues to be developed apace.
In developing its own such technology, Proterra says its ultimate aim is to deliver an electric bus that can serve any typical transit route in the US. It points out that General Transit Feed Specification data shows that typical US urban and rural bus routes cover less than 200 mi (322 km) a day. This means that the most routes in the country are now within the range of the Catalyst XR.
The bus tested was fitted with a new generation of storage technology comprising eight battery packs and providing a total energy capacity of 257 kWh. Not only was the storage technology developed to achieve an increased range, but the bus itself is said to have been designed entirely with range and efficiency in mind, with an aerodynamic body made from carbon fiber and advanced composite materials among its features.
"They really are the only transit vehicle that's been designed, engineered and built from the ground up to be an electric vehicle," explains CEO of Proterra Ryan Popple. "All of the previous attempts in this market have started with a steel vehicle that was designed to be a diesel or a natural gas vehicle."
The aim of the test was to achieve as high a mileage as possible on a single charge, with Proterra expecting to maybe achieve 200 mi (322 km). Being driven at an average speed of 30 mph (48 km/h), the Catalyst XR achieved an eventual distance of 258 mi (415 km), with an average energy consumption of 0.8 kWh/mi (0.5 kWh/km).
That distance is significantly larger than 155 mi (250 km) range of the BYD electric bus, which seems to be regarded as having the highest range otherwise. Furthermore, based on these results, Proterra believes its 10-pack XR configuration, which provides a total energy capacity of 321 kWh, could achieve 300 mi (483 km) on a single charge.
The Proterra Catalyst XR was tested at Michelin’s Laurens Proving Grounds.
The video below provides an insight into the test.