Petrol and Diesel - Delivering Quality
Regulations for petrol and diesel quality are being reviewed for the first time in 13 years, and the Ministry of Economic Development (MED) has released a discussion paper that seeks your feedback.
The quality of NZ's petrol and diesel is governed by the Petroleum Products Specifications Regulations. They include limits for components that could be harmful to the environment or to people's health, such as sulphur and benzene. They also specify standards for properties that affect the performance of fuel, such as the cetane number1 and cold weather performance measures.
Since the regulations were first issued in 1988, there have been developments in engine technologies, innovations in refining petrol and diesel, and changes in international petroleum standards - which haven't necessarily been matched by changes in the regulations. Any new regulations would aim to ensure that consumers can access petrol and diesel that complies with up-to-date quality, safety and environmental standards, as well as ensuring that we have fuel that suits modern engine technologies.
Changes to the regulations would potentially enable NZ to obtain newer technology vehicles, which are being made according to higher and more up-to-date international standards. However, several proposed changes to the fuel specifications would have costs as well as benefits and these need to be taken into account.
Proposed amendments to the diesel specifications include narrowing the density range, increasing the cetane number and reducing maximum sulphur levels2. Proposed changes for petrol specifications include reducing maximum benzene levels, reducing maximum sulphur levels and restricting the use of the petrol additive MTBE3.
Some Terms Defined
1Cetane Number. This number is a measure of how easily diesel fuel ignites in an engine. In diesel engines, fuel ignites of its own accord as the air/fuel mixture in the cylinder is compressed - there are no spark plugs. The higher the cetane number, the shorter the delay period from the start of fuel injection to the start of combustion. This results in smoother combustion, lower engine noise, and improved starting, particularly in cold conditions.
2Sulphur. This element is present in all crude oils. When crude oil is distilled into petrol and diesel fuel blending components, some sulphur finds its way into those components. The amount of sulphur allowed in petrol and diesel is limited because of the undesirable effects it causes during combustion, such as its odour, its corrosiveness, and its tendency to produce acidic by-products. In addition, sulphur in diesel contributes to the formation of particulate matter, a component of engine exhaust that is linked to health problems. Advanced technologies that are used to meet stringent emissions limits in both petrol and diesel vehicles generally require very low levels (less than 50 parts per million) of sulphur in order to operate effectively.
3MTBE. Methyl tertiary-butyl ether (MTBE) is sometimes blended with petrol to boost octane and improve combustion. MTBE and most other oxygenates, including ethanol, have an affinity for water. If water is present in a fuel (or the storage vessel), oxygenates will preferentially blend into the water and out of the petrol. In recent years, leaks from underground storage tanks in the US have tainted groundwater supplies. The levels of MTBE found in groundwater are not thought to be a health risk, but MTBE is persistent and imparts an unpleasant taste and odour, even at very low concentrations. As a result, many jurisdictions have banned the use of MTBE and other ethers in petrol. Australia has recently announced that MTBE will be limited to 1% by volume in its petrol.
Submissions close 15 October 2001. For more information on the review, or to get a copy of the public discussion paper, write to Fuel Quality, Resources and Networks Branch, Ministry of Economic Development, PO Box 1473, Wellington, or check out MED's website at www.med.govt.nz |
Contact for Enquiries
The Ministry of Agriculture and Forestry
Pastoral House
25 The Terrace
PO Box 2526, Wellington
Tel: 0800 00 83 33
Fax: +64 4 894 0720
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