Michelin Green X Challenge

State of Sustainable Racing 2012 Case Study


The Michelin Green X Challenge is a “race-within-a-race” that aims to reward teams competing in the American Le Mans Series (ALMS) for their attempts to mitigate the environmental impact of auto racing. It is not simply a test of who can cross the finish line first, but it judges teams based on their performance in terms of speed and emissions. Beginning in 2008, the Green Racing Protocols were developed by a collaboration between The Department of Energy, The Environmental Protection Agency, and SAE International to help guide professional racing towards more sustainable practices.

  • Vehicle Type: Le Mans Prototype 1 (LMP1); Le Mans Prototype 2 (LMP2); and Grand Touring (GT)
  • Fuel/Energy Source:  GTL Diesel, E10, E85, Hybrid E10-electric, and Isobutanol
  • Years in Production: 2009 – Present
  • Sponsors: Michelin Tires; Patron Tequila


The ALMS was the first and remains the only U.S. race series to adopt the Green Racing Protocols. Since 2009 all teams competing in the ALMS are judged based on criteria for the Michelin Green X Challenge, and a champion is awarded at each ALMS event in addition to the overall winner of the ALMS event. In 2011, Le Mans vehicles competing in the Michelin Green X Challenge utilized five different types of alternative fuels: GTL Diesel, E10, E85, Hybrid E10-electric, and Isobutanol.


Beginning in 2011, the Michelin Green X Challenge created a new tag line, “Clean, Fast and Efficient,” which guides their calculation of the champion.

Speed is determined quite simply by the vehicles average race speed. Efficiency is also determined during the race by placing a gauge in the vehicle’s fuel tank and dividing the total amount of fuel used by the car’s mass.

The clean factor employs metrics developed by the Argonne National Laboratory, which gives each fuel type a coefficient for its total emissions from “well to wheel” through life cycle analysis. Cleaner fuel types have a more advantageous coefficient, and teams can choose their type of fuel based on these criteria.

The aggregate scores are measured for each lap of the race, and the scores are normalized for speed and distance to match the race leader of each category. This is done to prevent cars that travel less distance or have slower average speed from having an advantage in terms of emissions released.

Learn More

Michelin Green X Challenge Website

Research by Dominican University’s Green MBA Program

Authors: Jake Baker, Robin Carew, Diana Connolly, Jack Decker

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