Why F1 Teams Can Use 'Illegal' Fuels in Testing
F1 teams can use non-certified 'surrogate' fuels in testing due to an unintended regulatory gap, a pragmatic move by the FIA to manage the complex rollout of new sustainable fuels. The practice allows suppliers to test chemical recipes without the full sustainable supply chain, with full certification required before the first race.
Formula 1 teams are permitted to use non-homologated 'surrogate' fuels during pre-season testing, a practice that stems from an unintended regulatory loophole. The FIA has adopted a pragmatic approach, allowing this flexibility to manage the complex introduction of new sustainable fuels ahead of the 2026 mandate, despite recent scrutiny over the legality of fuels like Mercedes' Petronas blend.
Why it matters:
This temporary allowance is crucial for managing the unprecedented logistical and technical challenge of sourcing fully certified, sustainable race fuels. It provides essential breathing room for suppliers to validate their complex new fuel recipes and secure the massive volumes needed for testing without risking a team's ability to run, ensuring a smoother transition to F1's greener future.
The Details:
- The 'Surrogate' Fuel: Teams are using fuels mixed to the exact chemical recipe of their intended race fuel. The key difference is that some components can be sourced from outside the mandated sustainable supply chain for testing purposes only, a cost and logistics workaround.
- Regulatory Origin: FIA Single-Seater Director Nikolas Tombazis clarified the rule was not explicitly written to require certified fuel in testing—an initial oversight. Recognizing the certification complexity, the FIA chose to permit this practice pragmatically rather than close the loophole immediately.
- Certification Complexity: The new process is far more rigorous than before. The FIA, aided by certifier Zemo, must now verify not just the fuel's chemistry and performance but also the sustainability and carbon footprint of every single component in a blend that can contain up to 100 different elements.
- The Mercedes Case: Reports questioned if Petronas fuel was illegal, prompting a strong denial from Team Principal Toto Wolff. The fuel in use is understood to be the advanced sustainable blend intended for the season, but in surrogate form during testing, a common practice across the grid.
What's Next:
The surrogate fuel window closes once testing ends. The FIA's firm target is for all fuels to be fully certified and compliant before the season-opening Australian Grand Prix.
- However, the intricate audit process means some suppliers could face a timing lag, having completed their work but awaiting final rubber-stamping from Zemo.
- This year acts as a critical learning phase for five major suppliers—Petronas, Shell, ExxonMobil, Aramco, and BP—as F1 refines its complex new fuel sustainability protocol ahead of the full 2026 regulations.