GUARDIAN NEWS SERVICE

By James Randerson

Steam power is poised to make a comeback as a way of using heat wasted by car exhausts. A British firm is developing steam hybrids in an effort to make engines more efficient.

Clean Power Technologies (CPT), based in East Sussex, in the south of England, aims to build a car engine that runs partly on steam power. "When you talk of steam people think you are going backwards," said Abdul Mitha, the company's president. "[But] anywhere where you are wasting a lot of heat, we can go in, capture the heat and turn it into energy savings.

"Steam has tremendous power. If it can drive a steam locomotive, why can't it drive an automotive engine?"

Of the energy in a car's petrol tank, just 27% is converted into forward motion, while 36% is lost as exhaust heat. CPT aims to recover 40% of this heat energy.

Dr Ralph Clague, a mechanical engineer at Imperial College London, says there has been little incentive to improve the efficiency of car engines in the past: "A tank of petrol or a tank of diesel is such an incredibly good energy store that we have been able to afford to throw some of it away up until now."

Ultimately, the aim is to pipe the steam back for use in the engine, but the first step for the company is using it to run refrigeration units on trucks that transport frozen goods. The firm has interest from the Safeway supermarket chain in the US - currently each of the supermarket's trucks uses up to $15,000 of diesel a year to power the refrigeration unit.