Assessment of the OSPAR Report on Discharges, Spills and Emissions from Offshore Installations, 2009 – 2019
This report presents the discharges, spills and emissions data from offshore installations in the OSPAR maritime area for the period 2009-2019 and provides an assessment of that data. The assessment is based on the data provided to OSPAR by Contracting Parties and published in the annual reports on discharges, spills and emissions from offshore oil and gas installations.
An assessment period of eleven years has been chosen for this report in order to support the OSPAR Quality Status Report due for publication in 2023.
a. Level of Activity
The OSPAR maritime area is a mature oil and gas region with the majority of Contracting Parties experiencing declining production. The total production of hydrocarbons in OSPAR’s maritime area has decreased by 28 % over the last eleven years, though there was an increase between 2014 to 2016 before starting to decline again. Despite this, oil and gas exploration and development activities continue in order to maximise economic recovery of reserves. The number of wells drilled during the period has varied from a peak of 490 in 2017, to 366 in 2014 and 443 in 2019. Despite the long-term production decrease there had been a 14 % increase in the number of oil & gas installations reported from 2009 up to 2015, with the greatest increase in the number of subsea installations used to recover hydrocarbons from marginal fields. The number of installations subsequently declined by 12 % from 2015 due to an increase in cessation of production and decommissioning with the drop in the oil price. The number of installations reported in 2019 (676) is nearly the same as in 2009 (674). It should be noted however that reporting of the number of installations has changed for some Contracting Parties during this period with the UK amending its approach in 2010 which resulted in an increase in the numbers reported by approximately 70 installations between 2009 and 2010.
b. Discharges & Spills of Oil
Discharges of oil continue to decrease
The amount of dispersed oil discharged in 2019 is 16 % below that discharged in 2009. While there was not a year on year decrease the total quantity of dispersed oil (aliphatic oil) discharged to the sea from produced water and displacement water decreased from 4 890 tonnes in 2009 to 4 096 tonnes in 2019. There had been a notable increase in dispersed oil discharged in 2015 as a result of an increase in the amount of produced water discharged and average dispersed oil concentrations.
As in previous years, produced water and displacement water are the main contributors to the oil discharges from offshore oil and gas activities, representing 95-99 % of the total amount of oil discharged to the sea during the 2009 - 2019 period. The exception was in 2011-2012 where a single large spill event accounted for 11-12 % of the total oil to sea. Flaring is a minor source of oil discharges and is not covered by OSPAR measures.
It should be noted that dispersed oil in displacement water contributes less than 1 % to this total.
As might be expected, the quantity of oil spilled has varied over the period, ranging from 44 tonnes in 2016 up to 541 tonnes in 2012, the later due to a single large incident in which 400 tonnes were spilled. There has been a downward trend in the number of oil spills over the period.
The concentration of dispersed oil in produced water is below the performance standard for most installations
The annual average dispersed oil content in produced water ranged from 12.4 mg/l to 14.1 mg/l over the period, well below the current performance standard for dispersed oil of 30 mg/l for produced water discharged into the sea.
In 2019, 17 installations exceeded the 30 mg/l performance standard for dispersed oil in produced water. The amount of oil discharged from six of these installations is less than 2 tonnes annually. In total, the discharge of dispersed oil in excess of the performance standard is less than 2 % of the total discharge of dispersed oil in the OSPAR region.
Most chemicals used and discharged offshore are considered to pose little or no risk
Since 2001 the use and discharge of chemicals have been regulated by OSPAR measures. The first reporting year for which all major contributors provided data was 2003. The total quantity of chemicals used offshore decreased from a peak of 838 111 tonnes in 2009 to 733 598 tonnes in 2019. In 2019 less than 1 % (by weight) of the chemicals used contain either substances on the OSPAR List of Chemicals for Priority Action (LCPA) or substances which are candidates for substitution.
The total quantity of chemicals discharged into the sea decreased from a peak of 293 402 tonnes in 2009 to 204 570 tonnes in 2019, 84 % of which were chemicals on the OSPAR PLONOR list. Less than 0,5 % (wt.) of the discharged chemicals contains LCPA substances or substances which are candidates for substitution.
OSPAR Recommendation 2005/2 set environmental goals for the reduction of substances on the OSPAR LCPA such that discharges were to be phased out by 2010. The discharge of LCPA was phased out by 2014, and other than a 3 kg accidental permitting of an LCPA discharge in 2016 in the UK and a 0.5 kg unpermitted discharge in Denmark in 2019 there have been no other discharges of LCPA.
OSPAR Recommendation 2006/3 sets out environmental goals on the phasing out of discharges of offshore chemicals that are, or which contain substances, identified as candidates for substitution by 2017 (the deadline has been extended to 2026). There has been a 42 % reduction in the discharge of such substances over the last 10 years.
The phasing out of the discharge of LCPAs and reductions in quantities of substitution chemicals discharged are indicative of the success of the OSPAR measures.
d. Atmospheric Emissions
Atmospheric emissions are stable or decreasing
Atmospheric emissions are not regulated by OSPAR measures, nonetheless, atmospheric emissions from offshore oil and gas activity are reported annually by operators. Emissions to the atmosphere have generally decreased or remained relatively stable for the period 2009-2019, with a 35 % decrease in methane emissions, 33 % decrease in SO2, 9 % reduction in NOx, 8 % decreases in CO2 and 7 % decrease in nmVOC’s.