Emissions of ozonedepleting gases by the norwegian fishing industry

Atle Kjærvik

Losses of chlorofluorcarbons (CFC gases) from Norwegian ships' refrigeration and freezing systems and from fish-processing plants ashore, come to around 136 tons a year. These are primarily due to a large number of small leakages caused by rust, claim reports from NTH/SINTEF

"Rust attacks are most likely to occur under insulation of this sort", warns Ivar Larssen of SINTEF.

"In addition to the threat that such leaks present to the environment, refilling up systems with refrigerant costs this industry about NOK 6 million a year," estimates Ivar Larssen, a research engineer at SINTEF Refrigeration Engineering. He says that some trawlers with which he has been in contact spend NOK 100,000 a year on refilling CFC gases. Larssen has not calculated the additional costs of down-time, maintenance and spares when cooling systems fail, but he believes that these are at least as great as the costs of refills themselves.

Poor-quality plants

Larssen's study aimed primarily to identify the causes of leaks and offer guidelines for the more environmentally friendly design, operation and maintenance of this type of system. His work was done in collaboration with the Research Council of Norway and is based on figures from a 1991 report written by Marit Sandbakk, another SINTEF scientist. The researchers made use of questionnaires and visited fishing vessels and fish-processing plants in order to survey the emissions. Although their material is not as comprehensive as they might have wished, write the researchers, their conclusions are unambiguous.

Larssen has demonstrated that the emissions are primarily caused by large numbers of small leakages from systems that cannot withstand the hostile, humid environment in which they have been installed.

"Particular parts of these systems, as well as some aspects of design, especially in humid areas, have been poorly thought out by manufacturers. Poor design and workmanship and selection of the wrong materials are the usual causes of the widespread occurrence of rust in these systems, particularly in the fishing fleet," Larssen points out .

"There is every reason to suppose that between 50 and 60% of total emissions are due to small leaks, in and around valves. Together with corrosion in pipes and tanks, these small leaks make the biggest contribution to disapperance over time. Insofar as large acute leakages occur, most of these are due to serious rust damage," he says.

Measures to combat leakages

Releases of HKFK R-22 (Monochlorodifluoromethane), the most usual refrigerant used by the fishing industry, come to about 127 tons a year from that industry alone, according to Sandbakk's study. This is on top of about 8.2 tons of CFC-502 and nearly a ton of CFC-12. Emissions of HCFC-22 are equivalent to about 20% of Norway´s total annual consumption of this gas, which lies at around 640 tons a year. (This figure includes supplies of HCFC-22 to new facilities, around one third of the total).

"Losses from shore-based fish-processing plants come to about 15% a year, while from vessels the figure is around 20%", Sandbakk reports.

Self-imposed tax

At present, the CFC gases are not subject to environmental tax, but according to Monika Ness of the Ministry of Environment, the industry operates under a self-imposed tax that brings the official price of HCFC 22 up to NOK 55 per kilo. This means that refilling this gas alone cost nearly NOK 7 million kroner a year. However, Larssen's sources have supplied an average price of NOK 35 per kilo, which gives an annual "topping-up charge" of NOK 4.5 million a year.

Paul-Gustav Remøy, section manager in the Norwegian Association of Fishing Vessel Owners, does not dispute the scientists' figures. However, he claims that the proportion of catches processed on board is increasing, and that the mean age of fishing vessels in 22 years. Nor does he regard it as remarkable that vessels visiting foreign ports take the opportunity of buying refrigerants at a more reasonable price. "This is simply the effect of special national taxes," believes Remøy.

The Norwegian authorities are currently evaluating the possibility of introducing an environmental tax on HCFC gases, like that of Sweden. This could result in a price of NOK 300 per kilo for HFCF-22, a price that would have major implications for the fishing industry. "The motivation to upgrade refrigeration plants and operate them in a more environmentally responsible fashion will be dramatically strengthened," thinks Ivar Larssen.