Bioliquids: The Renewable Fuel Reshaping Marine Power Generation
Walk through any engine room retrofit conversation these days and one word keeps surfacing: bioliquids. Shipowners chasing decarbonisation targets, power plant operators hedging against volatile fossil fuel markets, and engine manufacturers racing to future-proof their product lines are all circling the same liquid renewable fuels. Bioliquids aren’t a single product but a broad family of plant, animal, and waste-derived fuels that can replace or blend with conventional heavy fuel oil and diesel in combustion engines, often with minimal hardware changes.
What Exactly Are Bioliquids?
Bioliquids are liquid fuels produced from biomass — organic material of biological origin — intended for energy purposes other than transport fuel, which falls under the separate biofuels classification used in road and aviation sectors. In practice, the category covers vegetable oils like palm, soy, and rapeseed oil, used cooking oil, animal fats, and various processed derivatives such as fatty acid methyl esters, better known as biodiesel or FAME. Pyrolysis oils derived from forestry residues and other lignocellulosic feedstocks also fall under this umbrella.
The appeal lies in chemistry that closely mirrors fossil fuel oil. Many bioliquids can be burned in existing diesel engines and dual-fuel engines with limited modification, particularly when blended with conventional fuel at ratios ranging from a few percent up to full substitution in engines specifically designed or adapted for pure bioliquid operation. Wärtsilä and other major engine builders have spent years testing combustion behaviour, viscosity management, injection system compatibility, and long-term wear patterns to validate these fuels across a widening range of blend ratios.
Unlike fossil-derived hydrocarbons, bioliquids are considered carbon neutral on a lifecycle basis because the carbon dioxide released during combustion roughly equals what the source biomass absorbed during growth. That accounting isn’t universally accepted without scrutiny — land-use change and feedstock sourcing matter enormously — but under recognised sustainability certification schemes, bioliquids deliver genuine greenhouse gas reductions compared to marine gas oil or heavy fuel oil.
Where Bioliquids Are Actually Being Used
The clearest adoption has happened in stationary and marine power generation rather than deep-sea propulsion, though both are converging fast. Island power utilities and remote grid operators have run bioliquid-fuelled engines for over a decade, drawn by energy security benefits and the ability to source feedstock locally rather than importing diesel. Power barges and floating generation units have followed similar logic, swapping heavy fuel oil for palm oil derivatives or used cooking oil blends without needing new vessels.
In shipping specifically, bioliquids are gaining traction as drop-in replacements during port calls, in auxiliary engines, and increasingly in main propulsion trials run by major container lines and cruise operators seeking near-term emissions cuts ahead of stricter IMO carbon intensity rules. Several ferry operators in Scandinavia and the Netherlands have already logged thousands of operating hours on biodiesel blends, reporting comparable performance to conventional fuel with reduced sulphur oxide and particulate output. Bunkering infrastructure remains the limiting factor — availability is concentrated around a handful of European ports — but that footprint is expanding as refiners and traders respond to demand signals from the EU’s FuelEU Maritime regulation and similar policy frameworks pushing fleets toward lower-carbon fuel mixes.
Challenges and Where the Technology Is Heading
Feedstock supply is the industry’s biggest headache. Scaling bioliquid production without triggering deforestation, competing with food crops, or straining waste oil collection networks requires careful sourcing and third-party certification, typically through schemes like ISCC or RSB. Price volatility tied to agricultural commodity markets also complicates long-term fuel contracts in a way traditional bunker fuel buyers aren’t used to managing.
Engine manufacturers are responding by widening fuel flexibility rather than betting on a single bioliquid type. Wärtsilä’s engine portfolio, for instance, now certifies operation on a range of bioliquid blends up to 100 percent in select configurations, reflecting an industry-wide shift toward multi-fuel capable platforms rather than single-fuel dependency. Advanced feedstocks — algae-based oils, lignin residues, and second-generation waste streams — are moving through pilot projects aimed at breaking the reliance on food-crop-derived oils entirely.
Bioliquids won’t single-handedly decarbonise shipping or power generation, but they offer something rarer than a perfect solution: a transition fuel that works in engines already on the water and already turning turbines. As certification standards tighten and feedstock diversity grows, expect bioliquids to remain a practical bridge technology while ammonia, methanol, and other zero-carbon fuels mature toward commercial scale.
