Porsche, Toyota: '1km LMP1 electric' rule is no gimmick

The two P1 factories competing in the WEC at present believe the rule, scheduled to come into force in 2020, fits with developments in the automotive industry.

Toyota Motorsport GmbH technical director Pascal Vasselon told Autosport: "This will be very similar to the plug-in hybrid technology in road cars where you use electric mode in the city and then go onto the internal combustion engine when you move onto the highway.

"Therefore, it is very relevant."

Porsche LMP1 team principal Andreas Seidl described the rule demanding zero-emissions running as "a natural move for the championship".

Vasselon stressed the importance of the WEC maintaining its road relevance in the face of a major cost-cutting drive for 2020 when a new rulebook will come into force.

He said it was important that LMP1 did not become a "super-Daytona Prototype international", a reference to the LMP2-based class for manufacturers competing in the IMSA SportsCar Championship in North America.

"Manufacturers such as Toyota have come into the WEC because it is an opportunity to showcase high-level technology that is relevant to road car development," he said.

"Everyone wants to save costs, but not at the expense of emptying the technological tank.

"We don't want a super-DPi, because then we would stop."

The so-called "one-kilometre rule" will go hand in hand with plug-in rapid charging for the P1 hybrid's batteries at pitstops.

There will also be a requirement for the P1 hybrids to finish all WEC races in electrical mode.

The rulemakers, the FIA and WEC promoter the Automobile Club de l'Ouest, intend to limit development costs by introducing a common charging system to be used by all manufacturers.

The road map for 2020 was announced ahead of last weekend's Le Mans 24 Hours.

It includes the introduction of moveable aerodynamics and strict limits on development.