The automotive industry faces a long road to fully decarbonize. Switching to entirely new powertrain technologies – electric, hydrogen, or others – takes years of development and even longer for full fleet turnover. Meanwhile, a faster, more immediate solution is gaining traction: “drop-in” fuels, which can drastically reduce emissions without requiring any vehicle modifications.
The Limits of Powertrain Changeovers
Transitioning away from internal combustion engines (ICE) is slow. New models take years to design and deploy, while debates over the “best” alternative (EVs, fuel cells, etc.) further delay widespread adoption. Blending biofuels into existing gasoline and diesel helps, but fossil fuels still dominate. The core problem isn’t just the technology, but the time it takes to replace hundreds of millions of existing vehicles.
Drop-In Fuels: A Near-Term Solution
Drop-in fuels are designed to work seamlessly in existing engines. Major automakers are now approving them for use in their vehicles, some selectively based on model year, others more broadly for newer cars. This is not a marginal improvement; these fuels can offer up to 90% CO₂ reduction compared to traditional fossil diesel.
HVO100: The Leading Drop-In Fuel
The most promising example is HVO100 (Hydrogenated Vegetable Oil), also known as renewable diesel. Unlike biodiesel (which contains fatty acid methyl ester and requires blending), HVO100 is chemically similar to conventional diesel, making it fully compatible with existing engines.
- Stellantis has validated its entire diesel range for HVO100, certifying many Euro 5 and 6 engines as compatible.
- BMW demonstrated how fleet operators could reduce their carbon footprint using carbon-neutral fuels alongside EVs.
- As of January 2024, all diesel BMWs produced in Germany are delivered pre-filled with 5–8 liters of HVO100.
Why Well-to-Wheel Matters
The 90% CO₂ reduction figure isn’t just about tailpipe emissions. It accounts for the entire fuel lifecycle: raw material extraction, refining, transport, and eventual combustion. This “well-to-wheel” analysis is crucial because it reveals the true environmental impact of any fuel source.
Scaling Up: The European Opportunity
With over 250 million vehicles in Europe, even a moderate shift to renewable fuels could have a significant impact. The key takeaway is clear: while long-term transitions to new powertrains are essential, drop-in fuels offer an immediate and effective way to reduce emissions from the existing vehicle fleet.
The adoption of these fuels is not just a technical possibility but is actively being implemented by major automakers, making it a viable near-term solution for decarbonizing transport.
