Karl Orton et Jonathan Anderson answer our questions

Pulse : Karl, Jonathan, can you start by outlining the energy mixes in the networks you help to run ?

Jonathan − Here in Australia, we are working with a broad mix. In Melbourne, for instance, we run the world’s largest tram network on electricity purchased from 100% renewable sources. At the other end of the scale, in Sydney, Brisbane, Perth, and Adelaide, we have whole bus networks which are still almost entirely fossil-powered. And there’s everything in between: we run rail services in South Australia, some on electrified lines, the rest diesel; and in Newcastle, the ferries and buses are diesel, but the light rail line uses an innovative catenary-free electric system…

Karl − In Sweden, we generate around 45% of our electricity from hydroelectric power and another 45% from nuclear. At Keolis, we have just over 1,700 buses on the road in the Stockholm, Gothenburg, and Borås urban areas, as well as the region of Dalarna, and all vehicles are running on alternative low-carbon fuels such as biogas (555) and biodiesel (over 1,000) and all electricity is procured from renewable sources.

Pulse : So you don't run electric buses ?

Karl – Currently, we have 59 in service – and they’ve proven quite complex to use. The operation is far more complicated than many people assume: not only do you have to refit the depot, you have to digitise it! Then there are all manner of changes to ways of working to take into account. It’s more straightforward to use biofuels: in many cases, you can simply convert existing diesel vehicles and then run them like usual.

Jonathan − Here in Australia, some PTAs are now stipulating that diesel buses be replaced with battery-electrics on retirement, but, to date, electrification has happened in the depots which are best suited: i.e. with the capacity for megawatt loads and the space for charging berths. Electrifying other sites is more challenging, although solutions have been found, like in Sydney, where we’re using pantographs to overcome space constraints. Not only does this allow for quicker charging than plug-in, it also increases the ratio of buses to berths from 2:1 to around 10:1 or more.

Pulse : So are PTAs wrong to specify electric traction as a way to reduce emissions ?

Karl − In Sweden, decarbonisation has been happening for decades now across the board. So when people ask about electric vehicles, I always ask them what specific problem they’re trying to solve. If you want to reduce carbon emissions, biofuels are often the simplest way of doing this quickly. That is, if you have access to large volumes of biofuels, which is not the case everywhere. Then again, biofuel buses still have combustion engines, so they produce other gaseous emissions, as well as noise: if you’re looking to improve here, electric might well be the better bet.

It also depends on what kind of service you need to run: short routes with high frequencies in urban areas like Stockholm are easier to electrify than trunk routes out in rural Dalarna. On the other hand, electricity is cheaper in northern Sweden, and biofuels are priced locally, too. So essentially, PTAs need to do total cost of ownership analyses based on their own regional structures first – and then decide.

Jonathan − I totally agree: energy-mix questions are always highly context-specific. Let me give you an example. Newcastle is at the centre of Australia’s coal industry, so decarbonisation will mean changes in the city’s economy. Luckily, the region has excellent possibilities for hydrogen: sun and wind for green electricity and, thanks to existing industrial infrastructure, storage and export facilities. So we’re pushing for a trial of 5-10 fuel-cell buses: hydrogen has a higher energy density than lithium batteries, giving equivalent ranges for less weight, but with all the benefits of electric drive-trains including better efficiency and less noise and maintenance requirements. I’m also talking to the PTA about trialling electric ferries: the Stockton service shuttles back and forth across 500 metres of quiet water and doesn’t run at night, so it would be absolutely perfect for light-weight electric boats.