When Renault Trucks brings diesel hybrids to the world, they won't run on electricity alone, even though customers would like them to. “We propose a hybrid that will never be purely electric,” said Robert Desportes, director of alternative fuel projects for the company. “The best answer is to have the electric motor boosting the acceleration.”

One client has asked Renault to develop a hybrid that would have an electric-only range of 50 km, but for that, said Desportes, “you need an electric truck or a bi-mode.”

There were examples of both at the Michelin Challenge Bibendum in France June 8-11. Renault Trucks displayed its 10-ton electric Midlum delivery truck with a range of 60 km on lead acid batteries that it makes with a partner for L'Oreal, the luxury goods company.

A small Italian company, Micro-Vett, presented its converted 3.5-ton Iveco Daily that can switch between the normal 2.4-liter diesel and a lead-acid battery pack that gives a silent running range of 25-30 km.

Customer interest in alternative powertrains is based mainly on silence. L'Oreal, which makes perfumes, wants to distinguish its delivery fleet in Paris with quiet delivery, even though the trucks cost twice as much with their 3 tons of batteries and electric motor. Micro-Vett has sold 10 trucks in Milan as ambulances that pick up their patients on diesel power but deliver them into the hospital quiet zone running on electricity.

The problem for Renault Trucks, and its sister brands Mack and Volvo, is a hybrid running on pure electricity would require two sets of controls for the steering and brakes — and if it were to have 50 km of range, would need 3 tons of battery. All that adds cost, said Desportes, and in the truck business “it is good to have it not too costly.”

Renault Trucks, AB Volvo and Mack Trucks will get a boost in their diesel hybrid development from Nissan Diesel, said Dany Boulanger, head of global marketing for Renault Trucks. Nissan Diesel has agreed to furnish trucks in the 7.5-18 ton Midlum class. AB Volvo and Mack Trucks have shown prototypes of heavy trucks using a hybrid system called I-SAM consisting of a combined starter, drive motor and alternator.

Aside from L'Oreal, only government units are supporting the cost of developing cleaner powertrains. The City of Paris is behind a Renault Trucks project — a garbage truck powered by natural gas — that adds 30,000 euros to the cost. Renault has delivered 200 of the trucks, and will deliver 200 more.