Demonstration Of A Comprehensive Approach To Monitoring Emissions From Oil and Gas Installations (AEOG)

Lead Research Organisation: University of Leeds
Department Name: NCAS

Abstract

Atmospheric concentrations of methane (CH4) and carbon dioxide (CO2) have increased significantly over the past century due to anthropogenic activity, with the UK offshore oil and gas sector is estimated to produce around 13.2 million tonnes of CO2 and 1.2 million tonnes CO2 equivalent of CH4. Offshore atmospheric emissions reporting are partly industry-led, from the initial permit through to the self-regulatory reporting using EEMS (Environment and Emissions Monitoring System). BEIS (Department for Business, Energy and Industrial Strategy), regards EEMS as a key element in its environmental regulatory function and data within is used for government reporting requirements and policy development and application. Emissions are self-regulated and there is no independent check on how the emissions reported in EEMS relate to the actual emissions. This proposal offers a new methodology whereby the EEMS and initial permitting can be validated using observations from research aircraft.
Currently offshore "atmospherics" permitting and reporting includes the emissions of carbon dioxide, nitrogen oxides, nitrous oxide, sulphur dioxide, carbon monoxide, methane and non-methane volatile organic compounds. Energy generation emissions are calculated from measured fuel use using emission factors based on total fuel combustion and / or stack sampling data. Flaring emissions are calculated based on total measured fuel combustion using emission factors. Venting emissions are based on total measured or estimated release volumes. Fugitive emissions are based on estimates relating to any recorded accidental release, and calculated losses based on the number of components and connections (thought to be the primary source of leaks) within an installation and its age. However, the methodology uses an age-related scale factor which becomes applicable when if the installation was built pre-1988. All of these approaches necessarily assume that there is a common set of standard factors, or installations can use their own factor from stack monitoring, that are universally applicable to all offshore oil and gas operating companies and their installations.
Direct measurement or monitoring of emissions offshore is limited because of significant logistical, health and safety and cost issues. It is therefore restricted to major combustion sources such as gas turbines. For most sources, emissions are calculated, based on activity data, for example using fuel consumption data or measured flare volumes allied with standard or installation specific emission factors, using measured or estimated venting volumes, or using industry standard estimates for fugitive losses. These methodologies carry a substantial risk that significant emissions may be missed, and any additional monitoring tool is of considerable interest to the industry, the regulator and the body responsible for compiling UK atmospheric emissions data.
Techniques developed by NCAS for monitoring gas plumes during the Elgin gas release, have demonstrated that airborne monitoring, coupled with innovative atmospheric modelling, can comprehensively survey large areas and many individual installations within hours (800 nautical miles covered in 4 hours at one altitude). This approach to emissions assessment estimates the total emission loads calculated from the elevation of various gases in the downwind plume. This approach has the potential to provide the regulator, BEIS, with new tools to validate emission levels, and has the potential to provide a monitoring method that is lower cost to the industry then regular stack monitoring surveys and more relevant to impact assessment.
The project will work together with BEIS and RICARDO to demonstrate how an airborne methodology can aid existing regulatory approaches, provide data that supports improved emissions estimates and give BEIS the confidence that that operators are reporting sensible and achievable estimates in their permits and EEMS reporting.

Planned Impact

Impact of future emissions.
This project will collect baseline atmospheric pollutant load data for the west of Shetland area, where a number of large developments are due to become operational during 2018. The baseline data set will provide a means of assessing the potential impact of emissions from the new developments (and other potential developments in the future) on regional atmospheric pollutant levels, and provide direct measurements for the relevant new installations. This is a unique opportunity to collect baseline data at a regional level.

Scale of atmospheric pollutant loads from specific installations.
The comprehensive data sets from specific northern North Sea installations will allow BEIS to directly compare atmospheric pollutant loads with operational activity reports made at the time of the airborne surveys. The loads can be directly compared with the results of modelling studies undertaken in support of atmospheric emissions permits.

Assessment of current emissions reporting methodologies.
The comprehensive data sets collected for specific installations can be compared with calculated emissions loads relating to the operational activities at the time of the surveys, derived using current EEMS methodologies, to determine whether the methodologies should be reviewed. It may also be possible to use pollutant ratios to discriminate between atmospheric loads relating to combustion activities and atmospheric loads relating to hydrocarbon releases, to determine whether there are issues relating to reporting methodologies for specific inputs (and possible under-reporting by operators). If the comparison indicates potential concerns in relation to the accuracy and reliability of the emission and activity factors used within EEMS, further work will be initiated to review the EEMS methodologies.

Independent assessment of whether current regulatory mechanisms could be usefully supplemented by airborne monitoring.
Current processes are based on annual pollutant loads included in emissions permit applications and permits; modelling of emissions to determine dispersion and potential local and regional impacts; annual reporting of emissions based on EEMS calculations; and stack sampling to confirm compliance with any relevant regulatory standards and to inform the emission factors included in the EEMS calculations. Comparison with the new data sets from airborne monitoring will allow BEIS to assess the effectiveness of existing systems and the benefits of innovative airborne monitoring. This will include estimates of the time, cost and accuracy associated with airborne monitoring. It is worth emphasising here that the airborne techniques to be employed are able to assess large numbers of individual installations and large areas within a short time - perhaps up to 10 in one 5 hour flight. Furthermore, if these techniques were to be fully implemented operationally it would be possible to deploy an aircraft with significantly lower operating costs than those required to do the initial development work (project partner Airtask will input advice on the optimum way to operationalize the developments from this project).

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