Currently, the emissions produced by the shipping industry are the same as the aviation industry. Put into context, this is roughly equivalent to the entire output of Germany. More worryingly, this set to rise along with increasing demand for global merchant shipping.
At current growth rates, shipping could be responsible for as much as 10% of greenhouse gas emissions by 2050. At the same time, the decreasing availability of light crude oil, and stricter marine fuel regulations around sulphur content in cheap 'bunker fuel' oils have produced even more incentive to find cleaner, competitively priced marine fuels.
WHAT PART CAN BIOFUELS PLAY TO GIVE SHIPPING A GREENER FUTURE?
Biology may hold the key to satisfying the need for cleaner marine fuels. Biofuels have several distinct advantages. So called 'drop-in' biofuels can be used as a like for like substitution for fossil fuels, with no or minimal modification to the ship's engine, and can use existing infrastructure.
This is important because the typical lifespan for container ships is 20-30 years which means about 2% of the fleet is replaced every year. Whilst expansion and replacement of the fleet with new vessels with cleaner propulsion systems from the get-go, there remains a need for like-for-like whilst alternative technologies and their supporting infrastructure are developed.
First generation or conventional biofuels) are produced from agricultural crops, vegetable oil or food waste, in much the same way as biodiesel. These can be used blended with existing fuels, or as a complete replacement.
By processing plant-based oils, it is possible to improve their efficiency and handling properties. For example, established fuel provider Peninsula recently launched a Biofuel Supply business, fuelling ships from used vegetable oils. The main challenges for uptake here are availability of suitably clean feedstocks, that don't displace acreage currently used to grown food. Innovators that can develop and protect new processes to convert unusably dirty feedstocks into viable fuels may therefore be able to leverage this advantage into an enviable position in the market.
Second generation or advanced biofuels are made of non-food biomass feedstocks like lignocellulosic biomass – residual feedstocks from forestry or crops. In particular, waste lignin, a waste product from paper pulp production, can also be a viable raw material for biofuel production as it has the highest energy density of all biomass components. This is the focus of the EU's IDEALFUEL project, and may be of particular interest in countries with established logging industries and infrastructure.
Going beyond lignin, Danish startup Kvasir Technologies have developed a feedstock-agnostic process, capable of processing not only lignin, but wood residue, sawdust, or any other biomass waste. Having this flexibility may help the technology to scale to different markets, based on the availability of feedstocks.
WHAT IS THE FUTURE FOR BIOFUELS IN THE MARITIME MARKET?
Looking ahead to the future, we expect to see third generation biofuels produced from algae and microbes without the need for a feedstock. This replicates the natural process through which oil accumulates but on an accelerated timeline – algae fix carbon dioxide through photosynthesis and are processed into oil-like hydrocarbon fractions.
For example, Cambridge-based HutanBio utilise microalgae to produce bio-oil from nothing but sunlight and carbon dioxide. The green credentials of this approach are supercharged when the CO2 is sourced from industrial flues and where the algae are grown in seawater. This reduces pressure on dwindling fresh water supplies, and actually converts this into water suitable for use in industrial processes. In this way, it may be possible for biofuels to not only reach carbon neutrality but have a positive or regenerative impact on the climate.
These technologies, however, are not without their challenges.
Marine biofuels are not currently cost competitive with fossil fuels. Unless oil prices remain between $60-100 a barrel this is likely to remain the case in the short-to-medium term. Additionally, the scale of production is potentially staggering. Even a pilot run in a small cargo ship will require thousands of tonnes of fuel. This may lead innovators to begin developing for the leisure and coastal markets, providing early profitability and a smaller scale proving ground ahead of expanding to oceangoing cargo ships.
BEWARE THE RISK OF GREENWASHING!
Finally, proving the environmental credentials and avoiding accusations of greenwashing or carbon double-accounting will be a challenge for any company wishing to position themselves as 'cleaner' or 'greener' than their competitors, or hoping to take advantage of future legal obligations for shipping to reduce carbon emissions.
The future of shipping propulsion seems hard to predict. Nuclear, electric, and wind are all poised to replace existing fossil fuels in the long term, but we cannot defer decarbonisation of existing shipping until these technologies come to fruition.
Technologies "twenty years away" may be too little, too late. As in every area of clean tech, a multifaceted, "yes-and" solution is necessary if we are to decarbonise in time. At least for the time being, a multifuel future appears the most likely way of keeping the flow of international trade moving.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.