The City of Johannesburg hopes to conclude a near-term feasibility study on the use of battery electric and fuel-cell buses by the end of 2019.

On completion, it could be possible to introduce an electric bus to the city’s bus fleet in a pilot implementation project in 2023, says City of Johannesburg green transport strategic support adviser Alex Bhiman.

Another possible step towards new, cleaner transport technology within the city is linked to the metro’s investigation of biogas production from its biowaste.

Bhiman notes that about 40% of commuters in Johannesburg travel to work by private car, 35% by minibus taxi, 6% by train and 5% by bus, with about 11% walking to work.

He says previous attempts to clean up the city’s bus fleet, through a diesel dual-fuel (DDF) initiative, did not entirely delivered the desired results.

DDF buses use both cleaner diesel (50 ppm) and compressed gas. This gas can either be natural or biogas.

The City of Johannesburg has 150 Euro V DDF buses. However, because of a lack of gas fuelling infrastructure, only about 25% of the DDF fleet runs on dual fuel, says Bhiman.

In order to be more efficient, two more gas filling stations have to be installed (at Roodepoort and Village Main), or most of the bus fleet has to be allocated to the Milpark depot.

Bhiman says the DDF fleet is not cost effective under the current operational conditions.

“Processes have to be implemented and improved to make operation and maintenance more effective.”

He adds that City of Johannesburg staff are currently being trained to take over maintenance of the DDF fleet from the bus manufacturer.

Bhiman regards the Euro V DDF fleet as a stepping stone from old to new technology. He says it is possible to fall back on the “cheapest options available”, which will, however, not reduce pollution. He regards it a better choice to move to newer technology, such as Euro VI engines, natural gas and electric buses, for example.

Considering the lessons learned from the introduction of DDF technology, Bhiman says investments in engines are not a complete solution, as the fuel and the engine are a single system.

He says the fuelling requirements of any technology must always be considered.

“This was a mistake from the DDF roll-out and we learned from this.”

Bhiman adds that any technology transition requires an investigation into the systems in place to support the technology and its fuels. This includes people, tools and infrastructure.

“We must consider the bigger picture and not only focus on the vehicle itself. “Ensure adequate planning and processes to engage all stakeholders to support a smooth transition.”

Bhiman also advises that it is best to choose well-established, well-supported and widely commercialised technologies.