What will 'green' cars of the future look like? A clue may be seen in the 24 Hours of Le Mans 2013 where the Green GT will add to a long history of environmental initiatives.

With the creation this year of a 56th pit dedicated to new technologies, researchers now have the opportunity to leave the strict framework of regulations to give free rein to their imagination. Nissan DeltaWing will go down in history as the first car to use this facility.

Even before 2012, the 24 Hours of Le Mans has always encouraged manufacturers to reduce fuel consumption of vehicles. Thus, before the era of environmental awareness, various initiatives have helped to make our cars consume less fossil fuel. These include aerodynamic body of the Adler in 1937 and the fuel injection engine of the Jaguar D-Type 1956.

However, it has only been since the early 80s that resolutely green ideas have been seen on the Le Mans circuit. Here are the highlights.

	Porsche Carburol (1980)
	Panoz Q9 (1998)
	Nazamax Judd (2003)
	Nissan DeltaWing (2012)
	Green GT H2 (2013)

1980 : Fuel prices were hitting a peak. The French government initiated the Carburol project intended to encourage the development of alternatives to hydrocarbons. The ambitious goal was to produce 50% of all fuel for road vehicles. The ACO supported the initiative and Thierry Perrier had the opportunity to enter the first car running with a green fuel, the Porsche 911 SC, powered by a mixture of ethanol and petrol finished 16th of the 24 Hours of Le Mans and won Group 4.

1995 : The Carburol plan has been abandoned and France is far from producing 50% of its energy needs in the transport sector ... This did not preclude the McLaren of  the Giroix Racing team from using a fuel composed of alcohol derived from sugar beet. The car finished 5th in class, which remains to this day the best result of a 'green' car in the 24 Hours of Le Mans.

1998 : Don Panoz launched the first hybrid race car in the history of the 24 hours. The power from the big 6 litre Ford engine was added to by an electric motor. Huge batteries were recharged during braking and returned energy under acceleration. It took more than ten years to see a similar KERS System (Kinetic Energy Recovery System) in Formula 1t. With a lap time of 3.53.199 the Panoz Q9 unfortunately did not qualify for the 24 Hours of Le Mans.

2003 : The British team Nasamax ran their Cosworth V8 on bio-ethanol. The following year the car was powered by a Judd V10, and was very competitive. It should be noted that the ACO allowed the use of a larger tank to compensate for greater fuel consumption. After starting in 14th position on the grid, the car finished 17th at the 24 Hours of Le Mans.

2008 : Biofuels used for all cars at the 24 Hours of Le Mans, through a fuel composed of 10% ethanol. The Diesels run on BTL (Biomass to Liquid). These second-generation biofuels, made ​​from non-edible parts of plants.

2011 : The Oreca of Swiss team Hy Tech became the first hybrid to be on the starting grid of the 24 hours. Equipped with a flywheel that stores energy during braking phases, the prototype retired after having coverd over 1500 km.

2012 : A double green year. On the one hand, the Audi e-tron quattro became is the first hybrid car to win the 24 Hours of Le Mans. On the other hand, the DeltaWing Nissan - with reduced drag coefficient - occupied the 56th pit and was performing well, when its race was interrupted by contact with a wall.

2013 : Second occupant of the 56th pit, the Green GT uses a Hydrogen fuel cell to produce electric power. Weighing 1240 kg, the H2 has two hydrogen tanks either side of the cockpit, while two radiators cool the fuel cell that is expected to produce 544 hp.

Julien Hergault

Illustration : Prototype design by Thomas Clavet and his group composed of Baptiste Viry, Julien Sarremejean, Matthieu Bouis and Romuald Lemoine, modelling in 3D.