Tranzit operates more than 100 BCI Diesel single- and double-decker buses in New Zealand. By successfully converting one to be 100 percent electric, they’ve found a way to keep the fleet running, even when diesel-powered public transport is phased out.

Tranzit received co-funding of $484,708 from the Low Emission Transport Fund(external link), which they matched with their own investment, for the project. The idea to convert diesel buses was born at the company’s Masterton headquarters during a conversation about alternative ways to decarbonise public transport.

Twenty months on, the electric bus has made its way from the Masterton workshop to Auckland, to begin trials on several routes with Auckland Transport.

The government announced in 2021 that it would phase diesel buses out of the public transport network, with councils only purchasing zero emissions buses by 2025, and decarbonising the entire fleet by 2035. Converting diesel buses ensures operators won’t be stuck with stranded assets, as they can have a second life as electric buses.

This project is a great example of what we can achieve and enable through the Low Emissions Transport Fund – it removes a fossil fuelled vehicle from the fleet and replaces it with electric.

Richard Briggs, Manager Transport Portfolio, EECA

Tranzit had a number of goals for what they’ve dubbed the “Repower Project”:

  • Demonstrate that repowers are technically feasible for single deck and double deck buses.
  • Achieve at least 230 kms of range on a repowered double deck bus.
  • Enable the bus to achieve dual plug charging at 300kwH (close to 400amps) which enables a charge time of 35-40 minutes.
  • Use the highly experienced Tranzit team to deliver this project so they continue to upskill their workshop team members and retain the intellectual property.

The conversion took a year to complete using a core team of five Tranzit mechanics with specialist training on electric vehicles. It proved to be extremely complex: Tranzit Project Manager James Howard says, “We completely stripped the bus of all its parts including the engine and wiring – leaving behind only the seating. Our team looked at the best location to install and fit the batteries and built special bracing to hold them, fit the electric engine as well as redesign the air conditioning and brakes systems and conduct general engineering.

“It was like a super brainy LEGO project – but with no instructions. After we built the bus, we pulled it apart and then rebuilt it with improvements. Then we pulled it apart again and rebuilt it with all the right blocks in the correct place whilst simultaneously writing the instruction manual for future conversions.”

A robust testing phase was carried out while the team ensured charging infrastructure was compatible with the Bus.

In January 2022, the bus entered regular service on the Metlink network in Wellington, but in early July, made the trip up to Auckland to drive test routs on Auckland Transport’s network.

Tranzit is planning a second conversion this autumn and gathering support for further conversions.

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