Figures from RNNP-AU show that there was no decline in the number of large crude-oil discharges in the period 2001-2015. The total number of acute oil discharges and the number of near-misses that could have produced acute oil discharges did however fall in the period.
"The downward trend in the number of incidents is not reflected in assessments of the degree of severity. Accordingly, there is still a need to discuss the effect of the barriers in terms of preventing acute discharges and staunching the development of incidents", says Finn Carlsen, technical director at the PSA.
"It is often the same barriers that prevent acute discharges as prevent major accidents and personal injuries. It is therefore important to examine assessments within the RNNP work in the contexts of personal injury, loss of life and acute pollution."
Acute discharges in the Barents Sea
In the last three years, there have been significantly more incidents in the Barents Sea than earlier in the period. This applies to acute crude-oil discharges, near-misses that could have resulted in major acute oil discharges and acute chemical discharges. The increase in the number of incidents coincides with increased activity in the sea area, and relates primarily to exploration drilling. The vast majority of actual acute discharges are chemical discharges and a quarter of these are greater than one cubic metre.
"There is obviously good reason to focus attention on barriers for preventing acute pollution in the Barents Sea. There is also a need to identify which may be area-specific challenges and which are more general ones", says Carlsen.
Chemicals are a concern
Post-2009, the number of acute chemical discharges on the NCS, taken together, has fluctuated around a high level. 2014 and 2015 saw the three largest acute chemical discharges in the period. Two of these concern drilling activities and the third occurred during loading/discharging of drilling fluid.
Chemicals are the clearly dominant type of spill on the NCS in the period, and make up 80% of all acute discharges with a volume of more than one cubic metre.
"We need to ask whether, in general, sufficient attention is paid to the risk of acute chemical discharges and whether barriers to prevent such discharges are adequately monitored", says Carlsen.
Acute discharges from subsea facilities
Petroleum activity on the NCS is characterised by extensive use of underwater technology and a large number of subsea facilities. There is no particular trend in the number of acute discharges from subsea facilities in the period, but some of the acute discharges from such facilities have been large-volume ones.
"This area warrants greater attention. It is important to reduce uncertainty concerning acute discharges from subsea facilities, and the companies must clarify how they are working on continuous improvements in respect of this type of incident", says Carlsen.
"There is a particular need to prioritise the development of technology for detecting underwater leaks at source and barriers that prevent minor acute discharges persisting and producing significant volumes of spill over time."