Sydney has recorded its hottest August day since 1995 as parts of Australia swelter through a warm and windy end to winter, and what is almost certain to be the country’s hottest August on record.
The city’s official weather station at Observatory Hill recorded a maximum of 30.2C at 2.30pm. The city’s overall record August temperature set in 1995 was 31.3C.
Studies show electrifying passenger vehicles and trucks will greatly reduce greenhouse gas emissions. But the switch to electric vehicles is slow. It won’t be enough to reach net-zero by 2050.
Other strategies are needed. That’s where the concept of “mode shift” comes in. It involves shifting passengers and freight to lower-emission forms of transport such as electric rail and shipping.
In two new research papers, a colleague and I show what a big impact this could have on Australia’s emissions. We used the Inland Rail project linking Brisbane and Melbourne as a case study of the potential impacts of shifts between land-based transport, shipping and aviation. (The route comprises 12 sections, some already operational, some being built and others in the planning phase.) We modelled the total emissions of these modes for three years: 2019, 2030 and 2050.
We found electric rail is hands down the land transport mode with the lowest emissions intensity (the amount of greenhouse gas produced per kilometre travelled) for both passengers and freight. When we included air and sea transport, we found electric rail and shipping have the lowest emissions. Air transport in Australia is in a class of its own as its emissions performance is so much worse than other modes, particularly for freight.
It will be very hard to reach zero emissions in the transport sector in a timely fashion. To get there will require all hands on deck for the freight sector but also for personal travel and the choices we make.
Current domestic emissions by transport mode are skewed. The vast bulk (85%) of total annual carbon-dioxide-equivalent (CO?-e) emissions comes from road transport. It’s followed by air (8%), rail (4%) and sea (2%) transport.
To fairly assess performance, we used the well-to-wheel/wake approach. It includes both direct and indirect emissions from producing, distributing and using fossil fuels, hydrogen and electricity. We calculated these emissions for 2019, 2030 and 2050.
These figures do not yet include non-domestic emissions created by Australian aviation and shipping activities overseas. Including these will greatly increase total emissions from these modes.
For passengers, air transport had the highest emission intensity. It is an energy-intensive mode of transport and has climate effects in addition to those caused by its CO? emissions, as I outline below. Including these effects, we estimated air transport’s emission intensity to be 1.7 to 2.8 times higher than for road transport.
From an emissions perspective, high-speed electric rail is a great alternative to road and air transport for travel between capital cities. It would result in deep emission cuts varying from 75–95%.
Average well-to-wheel emission intensity for passenger transport. (Dashed line = mean, shading = 99.7% confidence interval, ‘Air’ = aircraft, ‘RF’ = radiative forcing, ‘Rail E’ = electric trains)Author provided, Transport Energy/Emission Research (TER)
For freight in 2019, ships performed much better than any other mode. This included electric rail, due to the relatively high emission intensity of grid electricity at the time. As renewable sources replace fossil fuel generation, electric rail’s emission intensity will improve.
By 2050, bulk carriers and electric rail were estimated to have the lowest emission intensity of all modes. Shifting freight to these modes would deliver deep emission cuts varying from 50–99%.
Air transport performed particularly poorly for moving freight. Its emissions intensity was, on average, 96 to 265 times higher (including the non-CO? climate effects of aircraft) than that of electric rail, for instance.
Average well-to-wheel/wake emission intensity for freight transport. (Dashed line = mean, shading = 99.7% confidence interval, ‘Rail D’ = diesel trains, ‘Rail E’ = electric trains, ‘Sea B’ = bulk carriers, ‘Sea C’ = container ships. Please NOTE that aircraft are not included due to the impact of its high emissions on chart readability.Author provided, Transport Energy/Emission Research (TER)
How did the study reach these conclusions?
Modelling the impacts of transport mode shifts on emissions is complex, country-specific and changes over time. It involves a broad range of inputs and information. Each mode has its own challenges and specific details to be considered.
For instance, aviation and shipping operate in the air and water. This means the modelling must account for winds and currents.
As another example, the practice of “slow steaming” – when cargo ships reduce their speed to cut fuel use and emissions – was considered for shipping.
For aircraft, there are additional net radiative forcing effects. (Radiative forcing is a measure of the influence a climatic factor has on the radiant energy impacting Earth’s surface.) These effects are complex and include the formation of contrails (condensation trails), aircraft-induced clouds and ozone formation (secondary air pollutant).
The analysis was based on statistical modelling. That is, instead of estimating single emission values, we quantified the most likely value and a plausible range in emissions performance.
It is also very important that the estimates reflect Australian conditions. For instance, we specifically modelled emissions from ship types and sizes (bulk carrier and container ships) and aircraft (A320 and B737) commonly used in Australia.
The modelling included mode-specific aspects such as vehicle weight and capacity, passenger occupancy, payload, annual passenger and freight volumes, operational profiles, future efficiency improvements and travel distance.
Travel distance can be surprisingly different between modes, as the map below shows. Air transport generally has the smallest travel distance. Sea transport routes can be much longer (about 60%).
What does this mean for policy and people?
Mode shift from road and air to rail and shipping has unused potential in Australia. Our findings suggests governments should, where possible, promote this shift for environmental and climate change reasons.
Clearly, other aspects such as costs and practical barriers need to be considered. But, from an emissions perspective, mode shift could get the Australian transport sector much closer to net zero.
And, as individuals, we can often reduce our own impacts by choosing not to travel or using lower-emission transport modes for our personal travel and the products we buy.
Robin Smit is the founding Research Director at the Transport Energy/Emission Research (TER) consultancy.
Like the petroleum industry itself, households are heavily invested in existing transport technologies. Getting oil and gas companies – and consumers – to switch to zero-emissions transport is a huge challenge.
We can’t presume battery electric vehicles (EVs) will displace fossil fuel vehicles any time soon. They are not accessible to most households and don’t offer radically better transport services. They drive on the same congested roads with the same speed limits.
On the supply side, electrifying entire transport fleets requires major infrastructure expansions. Even with strong demand, such infrastructures will struggle to displace Big Oil’s dominant and affordable alternative.
It’s a classic chicken-and-egg predicament. Consumers and vehicle makers won’t switch unless they are confident the required refuelling infrastructures will be available. But those infrastructures won’t materialise without sufficient demand.
Repurposing existing infrastructure to supply clean fuels could convince both consumers and vehicle manufacturers to make the switch. But what would that take?
Clean fuel alternatives
Major economies (including the United States, European Union and Japan) and car manufacturers, such as Toyota and BMW, are actively promoting clean hydrogen-based technologies such as hydrogen fuel cell vehicles. Toyota and some heavy vehicle manufacturers are also investing in vehicles that could combust clean hydrogen.
Whether “green hydrogen” might work for mass transport remains hotly debated. But it’s not the only possibility – biofuels made from renewable feedstocks have the potential to at least partly decarbonise transport (especially aviation).
And so?called “drop-in fuels” could also substitute for fossil fuels. Known as e?fuels, these are synthetic fuels made by combining hydrogen with carbon dioxide.
As such they could decarbonise transport faster and more widely because they can be used in existing vehicles – and supplied via existing infrastructures. A recent EU ban on new fossil fuel vehicle sales from 2035 was softened to allow for this.
As with EVs, vehicles running on clean hydrogen, biofuels or e?fuels don’t revolutionise transport beyond reducing emissions. But they might get a head start on EVs by solving that chicken-and-egg problem: making possible the conversion of entire vehicle fleets to run on clean fuels, while developing the required refuelling infrastructures.
Electric vehicles charging in China: mass electrification requires massive new infrastructure.
Affordability and scale
Repurposing existing fossil fuel infrastructures to supply clean fuels could be faster and cheaper than building new ones, such as the massively expanded electricity systems required for mass EV adoption.
For example, zero-emissions hydrogen can be produced from natural gas, but the process itself produces greenhouse gas emissions. Carbon capture storage (CCS) – removing the emissions and storing them securely in geological structures such as depleted gas fields – is one possible solution.
The Intergovernmental Panel on Climate Change sees CCS as feasible and playing a significant role in reducing greenhouse emissions. This would mean oil companies could adapt to producing zero-emissions hydrogen while renewable hydrogen or e?fuel production develops.
The required geological structures are located near oil and gas infrastructures, which could also be converted to transport the resulting clean fuels.
These technologies might not yet be economically viable. But the same was true of EVs only 20 years ago. Concerted investment – and production at scale – was pivotal in improving their economics.
Repurposing fossil fuel infrastructures also opens the door to converting existing vehicles to run on clean fuels. This requires little or no modification for drop-in fuels, which are substitutable for existing fuels by design. Alternatively, vehicles can be converted to combust clean hydrogen (or dual fuel mixtures).
This could be much more affordable – and attractive to vehicle owners – than buying new vehicles (even assuming suitable options were available).
Putting coal out of business
In the process, Big Oil could avoid its existing assets becoming sunset investments. Critically, it could also profit from repurposing its infrastructures, by decarbonising sectors currently dominated by the other major carbon polluter, coal.
For example, hydrogen is a more credible substitute than electrification in some large coal-consuming industries, such as steelmaking.
However, given the need for scale and co?ordination, it’s unlikely individual oil and gas companies could profitably repurpose their infrastructures on their own.
But industry-wide agreement and co?ordination to produce a particular clean energy (or mix of energies) could substantially reduce investment risks. Laws against collusion would likely prohibit such agreements, so targeted exemptions and close regulatory oversight would be needed.
Relatedly, firms might commit to accelerating the green transition in return for regulated – but guaranteed – rates of return. While not perfect, this strategy has a precedent in the way competing US electricity utilities became regulated monopolies.
This has been used to support the rollout of other natural monopoly infrastructures such as water networks, toll roads, cable TV and fibre broadband. It creates a contest that Big Oil couldn’t afford to lose.
Once dominant but soon displaced: 1897 illustration of an early electric car made in France.Getty Images
Repurposing the past
History offers relevant lessons. EVs were once a dominant automobile technology over a century ago. But they were quickly displaced with the arrival of affordable and convenient fossil fuel vehicles.
Emerging clean fuels hold the promise of fast refuelling and long ranges, combined with zero emissions, meaning the days of EVs could again be numbered.
Recall, too, that 19th-century investors accelerated the transition to rail by buying canals that competed with trains. They then either retired them or repurposed them as rail routes.
Had those investors anticipated motorised vehicles and roads displacing rail, they likely would have invested less. That they didn’t means current generations benefit from access to more railways than would otherwise be available.
The same is potentially true for the fossil fuel industry. Past investment in polluting infrastructures could benefit current and future generations if repurposing those infrastructures accelerates the green transition.
Richard Meade does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
These unseasonal late-winter days of warmth and clear skies, of the sudden necessity of shorts and T-shirts for the morning dog walk, are at once glorious and somewhat disconcerting.
Spring – the season of renewal, of awakening, of birth and perhaps rebirth – demands to be celebrated. But somehow this year, all of its ridiculously early harbingers feel double-edged for their presaging of the realities of climate change and sea-level rise.
After a week of wild weather, some Tasmanians woke on Wednesday to a fresh sprinkle of snow. But as winter comes to a close, the Bureau of Meteorology says the state is on track to record its warmest August.
