The tightening of clean air and other environmental legislation means that the refinery industry will have to concentrate on developing hydrogen and fuel additives, according to senior industry experts.

More complex engine technology is also pushing fuel producers to look at new technology.

"Fuel additives are one of the cost-effective ways to get engines to do what they were designed for," said Patrice Bres, head of the special fuels division of refiner Total, according to Reuters.

With the European Union having put great restrictions on sulfur output, now requiring a maximum of 0.005 per cent sulfur, he said that refiners had to look to hydrogen additives as low-sulfur diesel caused a problem with high-pressure fuel injection engines.

"It all requires a lot of hydrogen, more conversion and more investment," said Norm Gilsdorf, senior vice-president of technology firm UOP LLC.

Demand for diesel is growing rapidly in Europe, as the fuel is much more efficient.

According to Reteurs, Mr Bres told a conference that his firm had started marketing a diesel additive that converts around 85 per cent of pollutant nitrogen oxide to water vapour and nitrogen.

Ÿ Adfero Ltd