Biodiesel, Renewable Diesel, SAF, and Maritime Biofuels: What are they?

The world is shifting towards a lower-carbon future, and biofuels are emerging as crucial to this transition. Not only are they reducing emissions in cars and trucks, but they are also reducing emissions and carbon intensity in jets and ships. But what exactly are biofuels, and how do the different types – biodiesel, renewable diesel, sustainable aviation fuel (SAF), and maritime biofuels – differ? 

Understanding Biodiesel, Renewable Diesel, and SAF

Each biofuel has different characteristics, benefits, and production methods:

• Biodiesel: Derived from vegetable oils or animal fats, biodiesel is typically blended with conventional diesel. While it’s a renewable resource with reduced emissions compared to petroleum diesel, it can have higher NOx emissions and may face cold weather performance issues. Biodiesel was the original biofuel but has been surpassed in volume by renewable diesel in recent years. Renewable diesel has superior benefits to biodiesel.
• Renewable Diesel: Unlike biodiesel, renewable diesel undergoes a distinct production process, often using similar feedstocks. Chemically similar to petroleum diesel, it’s a “drop-in” fuel, which means it works just like diesel fuel in diesel engines without blending or engine modifications. It has better cold-weather performance but comes with higher production costs. Renewable diesel can reduce GHG emissions up to 80% vs. diesel.
• Sustainable Aviation Fuel (SAF): SAF is a game-changer for the aviation industry, significantly reducing emissions, up to 94% according to the EPA. Produced through various pathways like HEFA (hydroprocessed esters and fatty acids) or FT-SPK (Fischer-Tropsch synthetic paraffinic kerosene), scaling up its production and achieving cost-competitiveness remain key hurdles.

SAF is currently being produced at several locations in Texas: Houston, Port Arthur and Port Lavaca.

Maritime Biofuels: Charting a Course for Decarbonization

The maritime industry, a significant contributor to greenhouse gas emissions, is exploring biofuels as a potential solution. The EPA estimates larger ships contribute 3% of greenhouse gases.

• Challenges of Decarbonizing the Shipping Industry: Electrifying large vessels is a complex challenge, making alternative fuels attractive. Some people think because trucks and cars can easily be made to run on electricity, that the maritime industry should have priority for acquiring the feedstocks for biofuels. While battery power is possible for short haul shipping routes batteries are not practical for large ships over long distances.
• Potential of Biofuels in Maritime Transport: Biodiesel and renewable diesel, being drop-in fuels, can be readily used in existing ships, reducing emissions and improving air quality. However, scaling production for maritime needs and ensuring sustainability are ongoing problems without solutions.
• Emerging Biofuel Technologies for Shipping: Bio-LNG and bio-methanol are emerging options for shipping, highlighting the importance of continuous research and development to expand options. Much like renewable diesel and SAF, the scalability, availability of sustainable feedstocks, and the productions cost remain significant challenges.

Addressing the Issues and Charting a Way Forward

While biofuels hold immense promise, they are not without their challenges:

• Sustainability Concerns: Sustainable and cost-effective feedstocks are paramount to avoid unintended consequences like deforestation. Lifecycle assessments are crucial to evaluate the overall environmental impact.
• Scalability and Cost: Meeting the vast demands of industries like shipping requires significant scaling of biofuel production. Technological advancements and supportive government policies are key to reducing costs and increasing accessibility.
• Policy and Regulatory Landscape: Government incentives and global collaborations are essential to drive the adoption of biofuels and establish standardized practices.

Biodiesel, renewable diesel, and SAF each have unique attributes, catering to different industry sectors and needs. Their potential to decarbonize industries like shipping is clear. However, to fully realize this potential, addressing sustainability, scalability, and cost concerns is paramount. As research progresses and policies evolve, biofuels will play an increasingly central role in our journey to a more sustainable future. Without doubt there will not be just one, but many solutions to our climate crisis.