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The Trends with Marine and Aviation Fuel

  • 15 March 2021 15 March 2021
  • Aviation

The final article in our series, “The Energy Transition – Post-COVID 19”, considers some of the recent developments in sustainable fuels for the shipping and aviation sectors in the wake of the COVID-19 pandemic.

The state of sustainable marine fuels

The current leading options for clean maritime fuel are: ammonia, hydrogen, biofuels and methanol. However, most of these options are not yet cost-efficient and still present storage or safety issues for ship designers. Further, electrification of long-haul vessels is not yet commercially viable, as battery technology has not yet developed enough capacity to carry a 200,000 tonne vessel across an ocean without having to recharge. On a whole, developments thus far have yet to offer a complete solution to power large vessels across long distances while being economical, transportable and storable at the same time.

A recent study by Ricardo Energy & Environment, produced on behalf of transport campaign group Transport & Environment, indicated that for decarbonisation of the shipping sector, due to variety of vessel size, application and typical voyage length, the initial solution would likely be a combination of electrification, hydrogen, ammonia and synthetic hydrocarbon fuels such as e-diesel and e-kerosene.

According to the United Nations Conference on Trade and Development, shipping carries about 80% of trade goods globally. At the same time, based on a report by the Washington Post, shipping accounts for close to 3% of all energy-related carbon dioxide emissions. Despite these emissions being much lower than that of for land transport – discussed in the previous article in our series – the shipping industry appears to have recognised the limitations of reliance on fossil fuels in view of rising global demand for maritime services prior to the Covid-19 pandemic.

Particularly, the International Maritime Organisation (IMO), which is the division of the United Nations that regulates shipping, has committed to ensuring that the industry contributes to decarbonisation. It has adopted targets to, among others, reduce the carbon intensity of international shipping by 40%, from 2008 levels, by 2030 and to reduce greenhouse gas emissions by at least 50%, again from 2008 levels, by 2050.

In order to meet the IMO targets, given the forecast for growth in global trade, according to the Getting to Zero Coalition, zero-emission vessels will need to hit the water by 2030, and based on reports by Bloomberg, vessels would need to reduce carbon intensity by about 85% by 2050.

The state of sustainable aviation fuels

Considering the need for fuel to be lightweight yet having sufficiently high energy density to power long distance flights, the most viable option today for renewable aviation fuel is that of carbon-neutral biofuels. Biofuel technology has become well established and can be blended and used in existing jet engines without modifications. Some countries like Norway have already begun to implement biofuel blending obligations for the aviation industry similar to those being implemented for the road sector. However, biofuel production does have its issues such as scarce feedstock and the potential for encouraging deforestation where food production is displaced to grow feedstock.

Like with shipping, electrification for aviation does not seem to be viable, as current batteries are still too heavy for commercial flight – by some estimates, a Boeing 747 aircraft would require 10 times its weight in the most advanced batteries made today. According to the Energy Post, we are still a few decades away from fully electric aircraft.

Another option is that of hydrogen, which high energy density and low weight makes it a prime candidate for decarbonising air travel. However, the technology is largely in its infancy, with hydrogen-powered aircraft costing an estimated three times more to produce than the equivalent from fossil fuels based on current designs and technology, and actual hydrogen combustion aircraft engines still largely conceptual.

From the same above-mentioned study by Ricardo Energy & Environment, it was found that synthetic hydrocarbon fuels like e-kerosene – together with limited contribution from advanced biofuels – would be the most viable option for renewable aviation fuel in the next 20 to 30 years. However, synthetic fuel production, currently processed by electrolysing hydrogen and carbon dioxide using renewable electricity, is still highly energy-intensive and therefore prohibitively costly.

Figures provided by the Air Transport Action Group indicate that the global aviation sector produces about 2% of all human-induced carbon dioxide emissions, but that air transport carries only 0.5% of world trade shipments. Although aviation emissions are comparatively less than those from power generation or road transport, from an article by Frontier Economics, the rise of global air traffic in the long run – projected to double within the next 20 years – is estimated to bring the aviation sector’s share of carbon emissions to as high as 25% of the world’s carbon budget as anticipated by the Paris Accord.

Although airlines and aircraft manufacturers have always been incentivised to consume less fuel and improve jet engine efficiency, it appears to be some way off before the industry is able to look to renewable jet fuels to substantially reduce emissions.

The impacts of COVID-19 and going forward

The effects of the COVID-19 pandemic on the shipping and aviation sectors need not be overstated. As vaccines are rolled out and social distancing as well as lockdown measures are relaxed going forward, it is widely expected that both industries will see a recovery in the next two years.

Given that many renewable fuel options for shipping and aviation are still not commercially viable, it is likely that government regulations would have to play a major role in reducing emissions for the near future. With many countries choosing to implement stimulus policies to drive economic recovery post-pandemic, it could be an opportunity to kill two birds with one stone – for stimulus to be directed towards investments in green policies and technology. Nonetheless, the road to truly zero-carbon marine and air transportation seems to be a long one at this stage.


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