Advancing sustainable fuels for aviation and maritime industry

Nearly all fuel used today derives from fossil fuels. In reality, for hard-to-abate sectors like aviation, shipping and heavy road transport, there is limited availability of viable sustainable fuel available at the scale required to undertake a meaningful shift. The small pool of biofuel drawing on used cooking oil and tallow is expensive, variable in quality and difficult to access. Unlike passenger and lightweight vehicles - which can take advantage of advancing battery technology - aircraft and vessels carrying heavy payloads across oceans cannot, and will continue to require the energy density that liquid fuels provide.
The constraint at hand carries severe consequences. Global sustainable aviation fuel (SAF) production is expected to reach roughly 2.4 million tonnes this year - less than one percent of all aviation fuel consumed. The maritime industry, meanwhile, is pursuing wind-assist technologies, efficiency improvements, and dual-fuel vessels, but its transition to sustainable fuels remains problematic. Reaching net-zero by 2050 will require annual SAF output in the vicinity of 500 million tonnes - a more than 200-fold expansion within 24 years. Behind the crunch lie two linked constraints: limited availability of sustainable feedstocks and biocrudes suitable for refining, and insufficient biorefinery capacity. Refiners are, understandably, reluctant to commit capital without assurance of consistent feedstock supply.
While bio-based fuels already exist, their supply base is limited and, in certain respects, contentious. Crop-derived feedstocks - including corn, soy and palm - compete directly with food production and can drive land conversion, including the expansion of large-scale monocultures at the expense of natural ecosystems and, in some cases, primary forest. Used cooking oil and animal tallow belong to the more defensible alternatives, but their available supply is inherently limited and increasingly sought after. The dominant SAF production pathway today relies heavily on these and other lipid feedstocks, making diversification increasingly important. Under EU regulation, this constraint is reflected in policy: waste oils and fats sit in Annex IX, Part B of the Renewable Energy Directive and are capped at 1.7% of the transport fuel mix. Advanced feedstocks such as forestry residues, other lignocellulosic materials and algae can mitigate many of these pressures.
With freshwater already scarce and limited national land suitable for agriculture, balancing food security, energy security, and decarbonisation poses a formidable challenge for countries like Oman. Absent a domestic feedstock, Oman's alternative is longer term reliance on imported fuel, or imported feedstock for domestic refining.
Oman does possess, however, several thousand kilometres of pristine coastline, among the highest levels of solar irradiance globally, and extensive desert land with no competing agricultural value. These conditions offer a strong match for a newly identified marine microalga – Sphaerica - a feedstock with potentially high commercial as well as environmental value. Its cultivation can generate biocrude suitable for conversion into high-quality sustainable fuel, alongside biomass that can be used for other productive purposes.
This particular organism needs no freshwater but thrives in very high salinity seawater, and the water drawn into the system can be recycled through multiple cycles rather than extracted once and then discarded - a meaningful distinction for a country that already directs much of its scarce freshwater to agriculture.
Nor does it require arable soil. Cultivation takes place on land with no food-producing value, leaving soil health undisturbed, within an enclosed photobioreactor system designed not to degrade the land beneath it and using lightweight, modular construction. Genuine diversification means directing future investment towards feedstocks that can grow at scale and achieve acceptable cost structures without reproducing the sustainability problems associated with earlier generations of biofuels. Oman's coastline and sunlight give it the means to lead that shift.
I’m presently visiting the country, leading a delegation from a UK biotechnology company, HutanBio, which is dedicated to innovation in this respect. Taking part in the Oman Climate Week we benefit from conversation with multiple parties, exploring ways our bioenergy platform can be taken forward in Oman, thereby scaling production of a sustainable, quality bio/fuel, to serve Oman as well as international markets.
Oman – along with the wider region – continues to evolve as a vibrant hub for air passengers, air cargo, and maritime transport. The country stands to benefit substantially from switching to sustainable fuels, particularly as new technologies move towards full cost competitiveness. By pushing ahead with the bio-energy opportunities now taking shape, Oman has an opportunity to become a significant producer - and ultimately exporter - of sustainable fuels, produced domestically using resources the country has in abundance rather than those it must import. A rising fuel bill can thus be turned into the foundation for a new export industry, helping to diversify revenue as Vision 2040 intends rather than trading one import dependency for another.

Dominic Emery The writer is Chair of HutanBio and a veteran expert in climate change and the energy transition.