IMO likely to target NOx emissions: Chevron

The International Maritime Organisation (IMO) will "rapidly" expand nitrogen oxide (NOx) emission regulations, according to Chevron.

The IMO, which has already introduced a measure to control global sulphur emissions, has agreed to introduce two NOx Emission Control Areas (NECAs) in the North Sea and Baltic Sea from January 2021. These will apply to vessels built after the start of 2021.

"We now expect several other parts of the world to follow shortly," said Chevron Marine Lubricants' senior engineer Luc Verbeeke. With NECAs for diesel engines already in place in US and Caribbean waters, shipowners may be unable to avoid all these areas.

"Today when you build a new ship you could say that you will avoid the US, although this would be limiting and reduce vessel flexibility," Verbeeke said. "But can you afford to say you will avoid the US and Europe for the lifetime of your vessel?"

Shipping classification society DNV GL in July said the EU is concerned about NECAs and whether they will be sufficient to combat emissions. The IMO in May 2019 said that talks had begun over a potential Emission Control Area (ECA) in the Mediterranean covering NOx and sulphur emissions. This year the European Parliament's environment committee demanded proposals to extend NECAs to all European waters, including the Mediterranean.

Chevron said that the shipping industry has dealt with the IMO sulphur cap fairly well and noted 0.5pc sulphur fuel oil is normally a high-quality product. But some older engines struggled with new 0.5pc blends because of the calculated carbon aromaticity index (CCAI), a measure of fuel ignition quality. Most 0.5pc fuel oil has a lower CCAI than 3.5pc sulphur fuel oil (HSFO).

Chevron said vessels will have to keep engines in better shape than before the sulphur transition to be able to burn 0.5pc fuel oil efficiently, which can improve fuel economy. Engine cleanliness and efficiency can be diagnosed by monitoring changes in the composition of the marine lubricant using iron testing on-board.

A higher iron content in cylinder oil would point to engine corrosion caused by use of a lubricant with too low a base number (BN) to neutralise acids formed during combustion. Higher magnetic iron would point to abrasion of the engine and a high concentration of cat fines in the marine fuel of choice.

Most issues with 0.5pc fuel oil have not been to do with quality of the fuel or cylinder lubrication, Verbeeke said, but by incorrect fuel handling, cleaning or non-compliance with original equipment manufacturers (OEM) guidelines.

By George Collard and Catherine Caulfield