Healthier diesel coming to a pump near you

Healthier benefits of a $180 million upgrade at the Marsden Pt oil refinery are starting to flow through the fuel system as new low-sulphur diesel is pumped into gas tanks.

The upgrade has cut the sulphur content in diesel from 500 parts a million to 50 parts a million and the benzene content in petrol refined at Marsden Pt has also been cut from 3 per cent to 1 per cent.

All diesel sold in New Zealand from next January 1 must meet the new standards. Sulphur in diesel can increase the amount of the tiny particles (called particulates) that vehicles emit. These can cause respiratory illness.

Shell NZ fuels technical manager Dave Jacobson said introducing the fuels was a complex logistical task. Tanks at terminals and service stations were usually topped up regularly, but were now being run down to near empty, ready to take delivery of the new-spec fuel.

Over the next few months, the sulphur content of diesel would be reducing.

"You don't really want to operate the network down at the bottom of the tanks," said Jacobson.

Running tanks very low ran the risk of supplies at service stations drying up completely.

The new fuel has been produced at Marsden Pt since September 1. It is sent around the country by coastal tankers or by pipeline to Auckland.

Low-sulphur diesel is more expensive to refine, but the price of the new fuel at the pumps is not going to increase suddenly because of the new specifications. Prices of different fuels are based on benchmark prices, in New Zealand's case, at Singapore.

Owners of older diesel vehicles may have some trouble with the new fuel. Those affected will primarily be pre-1995 Japanese light-duty vehicles. This includes SUVs, courier vans and small trucks.