Skip to main content
Please Note: This is an archived snapshot of the latest published version: 1.0.0 Click here for the most recent published version

Ireland Assessment of Discharges, Spills and Emissions from Offshore Oil and Gas Installations in 2013 -17

Executive Summary

This report presents the discharge, spill and emission data for Irish offshore oil and gas operations during the period 2010 - 2017 and provides an assessment of those data. The data on which the assessment is based are provided in Appendix 2.

Level of Activity

Levels of oil and gas drilling and production activity offshore for Ireland have historically been low. Up to 2015 there was just one gas production installation, though with multiple well inputs from three gas fields. An additional gas production facility began operations at the end of 2015 but did not discharge produced water to sea over the period of this report. There is currently no oil production in Irish waters.

Full Report

The total production of gas from offshore Ireland during the period 2010 – 2015 decreased by nearly 30%, however production has increased approximately five-fold since then due to the coming on-line of the second installation.

Discharges and Spills of Oil

The total quantity of dispersed1 oil (aliphatic oil) discharged to the sea from produced water and displacement water has remained stable at around 0.02 tonnes per year.

The quantity of dispersed oil discharged by produced water in Irish waters is both relatively low and stable, therefore the main contributions to the total oil discharged remained relatively low but varied from year to year, depending on the quantity of oil spilled in a year. There is no apparent trend.

The annual average dispersed oil content in produced water had remained relatively stable from 2010 to 2013 at approximately 15 mgl-1. In 2014, the concentration of oil in produced water rose to 27 mgl-1 but  levels in  2015  were back down to previous concentrations. All levels were below the current performance standard of 30 mgl-1 dispersed oil in produced water discharged to the sea and so the OSPAR performance standard was consistently achieved over the reporting period. 

Quantities of oil spilled were low, ranging from 0.0 to 0.01, with one incident in 2012 of 0.7 tonnes. Amounts varied over the period, as might be expected. There is no trend in the data.


The total quantity of chemicals discharged into the sea during the period 2010 – 2017 remained in the same order of magnitude, increasing some years and decreasing others depending on the level of drilling activities. On average about 90% (by weight) of the chemicals discharged over the assessment period were on the OSPAR PLONOR list, while an average of less than 1% (by weight) of the total amount of chemicals discharged contained substances which are candidates for substitution.

OSPAR Recommendation 2005/2 set environmental goals for the reduction of discharges of LCPA substances, and discharges were to be phased out by 2010. This was achieved by Ireland, with no LCPA discharges in the assessment period.

OSPAR Recommendation 2006/3 set environmental goals on the phasing out of discharges of chemicals that are, or contain, substances identified as candidates for substitution  by 2017. In Irish waters, quantities of such chemicals used generally decreased during the period from 2010 - 2016. Discharge of such substances increased in 2017 due to hydraulic valve operations. As no other activity was underway in 2017, this increase has more relative impact.

Atmospheric Emissions

Atmospheric emissions from offshore oil and gas activities are not regulated by OSPAR measures, but are reported annually by operators. Emissions to the atmosphere had generally decreased or remained stable over much of the period, apart from 2013 where increases were attributed to the increased diesel consumption required for dynamic positioning (DP) during drilling of a deep-water well. A slight increase also occurred in 2017, again due to DP drilling operation.

Concluding Comment

The level of activity from offshore industry in Ireland is considerably lower than in most other OSPAR Contacting Parties. As a result of this low level activity, any additional activity impacts significantly on the data and thus impacts on any trends within.

The industry in Ireland is currently immature and therefore possibilities for further exploration or production activities in the future cannot be discounted.

1. “Aliphatics” and “aromatics” are defined by the reference method set in OSPAR Agreement 2005-15 (Solvent extraction, Infra-Red measurement at 3 wavelengths). In that context, “aliphatics” and “dispersed oil” mean the same thing