Exploring Biofuels As A Potential Maritime Fuel of the Future

Introduction

Biofuels are emerging as a crucial alternative to conventional fossil fuels in maritime transport, offering a more sustainable energy source for the shipping industry. As global regulations tighten on emissions and carbon footprints, biofuels—derived from renewable sources like algae, plant oils, and waste products—are gaining attention due to their potential to significantly reduce greenhouse gas emissions.

The maritime sector is currently responsible for around 2-3% of global CO2 emissions and thus exploring biofuels in shipping highlights their promise for greener oceanic transport.

Biofuel types

The EU-ETS and the Fuel EU Maritime Regulations are driving decarbonization in shipping. The EU ETS regulation (REGULATION (EU) 2023/957) mandates an EU-wide target of reducing net emissions by at least 55% by 2030 and achieving climate neutrality by 2050. As per FUEL regulation (REGULATION (EU) 2023/1805), the maritime sector will be mandated to reduce the carbon intensity of fuels by 2% by 2025, increasing to 6% by 2030, all the way to 80% by 2055!

Biofuels are a pivotal part of meeting these targets.

However, not all biofuels are equal in terms of GHG savings. Biofuels, made from renewable biological sources, have emerged as a key alternative to traditional fossil fuels. Apart from a few major grades like FAME, UCOME, HVO, and BTL, various biofuels are being produced and tested for maritime applications.

FAME (Fatty Acid Methyl Esters):

• FAME is commonly used as biodiesel and is made through the transesterification of oils and fats.
• Feedstocks include rapeseed oil, soybean oil, tallow, and used cooking oil.
• FAME has a high oxygen content, which can improve combustion but makes it prone to oxidation and degradation, requiring careful handling in storage. FAME has poor cold-flow properties.

UCOME (Used Cooking Oil Methyl Ester):

• UCOME is produced from waste oils, such as used cooking oil.
• Its primary advantage is a lower GHG (greenhouse gas) intensity as compared to virgin oils. By reusing waste, UCOME offers a lower well-to-wake (WTW) carbon footprint than fresh vegetable oil biodiesel. FAME, with lower energy density, requires a larger storage capacity.
• While UCOME is gaining traction due to its lower carbon footprint, feedstock availability limits its widespread adoption for large-scale shipping.

HVO (Hydrotreated Vegetable Oil):

• HVO is created by treating vegetable oils or animal fats with hydrogen, resulting in a cleaner-burning fuel than FAME. HVO has high energy density & superior cold flow properties, crucial for vessels operating in colder regions.
• Feedstocks for HVO include palm oil, tallow, and Used cooking Oil. The hydrotreating process removes oxygen, giving HVO better stability and energy density.
• HVO has a GHG intensity that varies by feedstock but generally performs well in emissions reduction, particularly when using waste-based sources like UCO.

BTL (Biomass-to-Liquid) Fuel

• BTL fuels are produced through gasification of biomass followed by a Fischer-Tropsch synthesis, creating a synthetic liquid fuel suitable for marine applications. Feedstocks for BTL include forestry residues, agricultural waste, and dedicated energy crops.
• BTL is advantageous due to its flexibility in feedstock use, which can help reduce reliance on traditional agricultural crops and mitigate competition with food sources.
• BTL has a high energy density and good cold flow properties, similar to HVO, making it suitable for long-distance marine routes. It has a relatively low GHG intensity and a favourable WTW emissions profile.

Bio Fuel Feedstocks

Feedstocks—the raw materials used to create these fuels—are at the heart of determining Biofuel sustainability and commercial viability.

Here are some of the major biofuel feedstocks currently in use, along with emerging ones that are likely to shape the future of biofuel production.

1. First-Generation Biofuel Feedstocks (Conventional)

These are primarily food-based crops, which have raised concerns about food versus fuel.

• Corn: Widely used in the U.S. for ethanol production, corn is a leading biofuel feedstock but is often criticized for its environmental impact and high water use.
• Sugarcane: Predominantly used in Brazil for ethanol production, it is more efficient than corn in terms of energy output but also has environmental concerns like deforestation.
• Soybean and Palm Oil: Used for biodiesel, these oils are extracted from crops that are grown in large volumes, though palm oil production has been linked to deforestation.

2. Second-Generation Biofuel Feedstocks (Cellulosic)

These feedstocks focus on non-food biomass, making them more sustainable and less controversial than first-generation feedstocks.

• Agricultural Residues (e.g., corn stover, rice straw, wheat straw): These materials are by-products of agriculture that would otherwise be waste.
• Grasses (e.g., switchgrass, miscanthus): These fast-growing perennial grasses are very efficient at capturing carbon dioxide and can be grown on marginal lands.
• Wood and Forestry Residues: Wood chips, sawdust, and other waste materials from forestry can be converted into biofuels, reducing waste.
• Municipal Solid Waste: Waste-to-energy technologies convert household and industrial waste into biofuel, which is especially useful in reducing landfill reliance.

3. Third-Generation Biofuel Feedstocks (Algal)

Algae are considered the next big thing in biofuel feedstocks due to their high yield and low land use.

• Microalgae and Macroalgae (seaweed): These organisms can produce large amounts of oil suitable for biodiesel or bioethanol. Algae grow much faster than land plants, can thrive in a variety of environments, and don’t compete with food crops.

4. Fourth-Generation Biofuel Feedstocks (Synthetic)

These are at the frontier of biofuel technology, using genetic engineering and carbon capture technologies.

• Genetically Engineered Microbes: Microorganisms, like bacteria, are being engineered to consume CO2 and produce biofuels, creating a closed carbon loop.
• CO2 Capture & Utilisation: This method aims to directly convert captured carbon dioxide into biofuels using biological or chemical processes. It’s still in the experimental stage but could offer a carbon-neutral solution.

Feedstocks of the Future: Emerging Trends

• Waste Oils and Grease: Used cooking oils and animal fats are increasingly being used to produce biodiesel. This has the dual benefit of reducing waste and producing energy.
• Aquatic Biomass: Seaweed farming and ocean-based algae production are being explored as future feedstocks that don’t require freshwater or arable land.
• Energy Crops on Marginal Lands: Plants like jatropha, camelina, and others that can grow on non-arable land are under research to prevent competition with food crops while providing renewable biofuels.

Challenges and Considerations

• Sustainability: Future biofuels must prioritize sustainability by using non-food feedstocks and minimizing environmental impacts like deforestation and water use.
• Technological Development: While first-generation biofuels are established, the second, third, and fourth generations will need further technological breakthroughs to become commercially viable.
• Cost competitiveness: Marine Biofuels are only slowly becoming cost-competitive with fossil fuels due to the supply-demand gap.

Conclusion

In summary, biofuel feedstocks such as used cooking oil, animal fats, and certain plant oils offer promising pathways for sustainable maritime fuel. Waste-based feedstocks like UCO and tallow have the lowest carbon footprint and align well with EU ETS and Fuel EU Maritime regulations, positioning them as ideal options for the industry’s decarbonization goals.

As regulations tighten and technology advances, we at Azolla are constantly looking for ways to reduce greenhouse gas emissions while maintaining operational efficiency onboard. Embracing sustainable feedstocks is crucial to navigating a future where environmental responsibility is a top priority.

You might also like to read:

• Green Fuels For Ships and Their Challenges
• Role of Seafarers in Maritime Decarbonization
• Why and How to Decarbonize the Marine Industry?
• Introduction To Methanol As A Sustainable Fuel For Ships
• Simplifying the Energy Efficiency Existing Ship Index (EEXI)
• Green Shipping COURSES

About Author

Azolla is a leading provider of sustainable solutions that drive decarbonization in the maritime industry. With a firm conviction that maritime professionals are key agents of change, Azolla endeavours to educate and empower individuals to embrace sustainable practices and lead the industry towards a carbon-neutral future. The writing team comprises of:

Kiran Shet, Head of Azolla
Aditya Srivatsava, Manager – Energy Efficiency & Decarbonization
Manav Chidambaran – Decarbonisation Specialist
Jothieswaran – Senior Naval Architect