Big batteries, green hydrogen and range extenders: The big plan to decarbonise rail fleet

Australian freight giant Aurizon has chosen battery and hydrogen power over renewable fuels to decarbonise its rail fleet in Australia.

CFO George Lippiat said in an investor day presentation last week that renewable fuels remain part of the plan to reach net zero by 2050, but high prices and a scarcity of feedstock predicted by the International Energy Agency in the coming years mean it may not be the best option if alternatives are available.

“That is part of our plan, but it’s reliant on the fuel being available at an affordable price,” Lippiat said.

Instead, Aurizon has signed up Caterpillar-owned Progress Rail in May to retrofit a battery into an existing 4000-class diesel locomotive, to see if it might be a cheaper way of transitioning locomotives with a 30-40 year lifespan away from fossil fuels.

The battery locomotive is expected to be finished by early 2025 and doing on-track trials in the first half of that year, with charging infrastructure being built concurrently.

Lippiat says of the company’s 700 locomotives, 150 are electric. But with shareholders, employees and other stakeholders demanding faster change, it has to be proactive.

“Our first platform is the battery electric locomotive or BEL. We think it can be deployed on hauls up to 400 kilometres on a single charge, and therefore cover about 30 per cent of our FY22 hauls, excluding bulk central and containerised freight,” he told investors.

“The concept is to reuse the parts of our assets that have remaining life and are well suited to our existing hauls.”

These will have 7 megawatt hours (MWh) of battery capacity.

Retrofitting may be cheaper than buying new locomotives, but it isn’t a simple process.

Progress Rail will need to strip the insides of the locomotive and remove the diesel engine, fuel tank, radiators, alternator, two traction inverters and other components.

It then needs to overhaul the drivers cab, the chassis, and bogies and traction motors in order to install lithium-ion battery packs, a control system, inverters for each axle, and an air compressor.

The next ideas are “range extenders” which could extend emissions-free haulage distances beyond 1500 kilometres.

The first option is to pull a second containerised battery pack to create a total capacity of 13.8 MWh behind the locomotive which would decarbonise another 50 per cent of routes.

The last option is to pull a hydrogen storage and fuel cell tender behind a battery-fed locomotive, which would allow Aurizon to use fossil fuel-free trains on its longest routes — the last 20 per cent of its haulage network.

Beyond 1500 kilometres, the company would look to modularise these units, for example by having battery transfer stations at key points to swap charged units in for depleted ones.

Aurizon has also commissioned the University of Queensland and Central Queensland University to model and research what emerging battery technology, network infrastructure and charging facilities will be needed to provide the renewable power for locomotive batteries.

Aurizon isn’t the first rail operator to test battery electric trains in Australia.

BHP ordered four 7MWh FLXdrive locomotives last year for delivery later this year, two from Progress Rail and two from American rail giant Wabtec.Around the same time Fortescue announced it was working on what it called the ‘infinity train’, powered by the gravitational energy created on downhill stretches. Little has been heard of this project since.