"Hybrid technology has been used for cars for five or 10 years now. The oil price, technology and the lower cost of batteries now makes it an efficient option for trucks and buses, too," Volvo Technical Director Lars-Goeran Moberg told AFP.

The development of hybrid technology has been hampered by the cost of batteries, but Volvo said that improved battery know-how, as well as predictions that the oil price would rise even higher, had made the technology viable and cost-effective.

"Within a few years we will show you a real vehicle that really works with hybrid technology for trucks and buses," chief executive Leif Johansson said at a presentation.

"This makes us weep with pleasure," he said.

The fuel bill for city buses, for example, could be cut by a third, which would allow operators to recoup the higher costs of buying hybrid engines within two years, he said.

More stringent emission rules in many countries added to the case for using hybrid technology for heavy vehicles, which would run pollution-free and virtually silently when powered by electricity, he said.

The US Air Force had already ordered five trucks, and Volvo said it hoped to launch production in partnership with its customers, notably city transport companies.

In hybrid technology, energy released during braking is stored in a battery, which powers an electrical engine that it typically used at low speeds. Once speed picks up, the diesel engine kicks in.

In addition to trucks, city buses and garbage trucks, the new generation of engines could also be used in construction and farm vehicles, as well as heavy machinery, Johansson said.

Volvo was currently spending 450 million kronor (57 million dollars, 48 million euros) per year on the development of the technology, rising to "several billion" once the production stage was reached.

Johansson said the technology was promising enough to attract competitors also, but he believed "that we are way, way ahead".

Related Links
Volvo