Environmental Sustainability

Atmospheric Emissions – Introduction and Background

Atmospheric emissions are gases released to the atmosphere through combustion processes and are an unavoidable by-product of oil and gas exploration and production. However, good regulation and legislation means that these emissions are as low as possible and gases are only released when necessary. The UK oil and gas industry keeps in-depth records of annual emissions to the atmosphere through EEMS (Environmental Emissions Monitoring System).

The majority of emissions from the UKCS are from those installations that produce oil and gas, and are generated by regular operation of the installation. Flaring also releases CO2 to the atmosphere, and is used offshore predominantly as a safety measure for burning off unusable waste gas or flammable gas and liquids released by pressure relief valves. Offshore flaring releases more CO2 than onshore flaring applications, however even when on- and offshore emissions are combined, less than 2 million tonnes of CO2 is released through this route each year. In comparison to the UK’s overall emissions of almost 600 million tonnes CO2 per year, the 2 million (0.33%) tonnes released from flaring is a relatively insignificant amount.

Atmospheric Emissions – Key Statistics and Commentary

NOx, SO2, CH4 and VOC’s (Volatile Organic Compound) all report a decrease in emissions whereas CO emissions have increased by 5000 tonnes. The data suggests an overall decreasing trend in atmospheric emissions for the Offshore Sector within the 5 year rolling period although as previously stated, the UKCS is a mature province; energy consumption relative to net production can be expected to increase as fields mature.

As reservoir pressures fall, production needs sustaining through pressure support and lifting methods, all of which require considerable energy input. This is compounded by the need to comply with other environmental legislation, such as reductions in oil-in-produced-water through use of energy-intensive re-injection.

UKCS Atmospheric Emissions of named gases 2001-2005

CO2 emissions for 2005 of 21,603,101 tonnes show a significant reduction of 1,292,835 tonnes from 2004;

UKCS Atmospheric Emissions of Carbon Dioxide 2001-2005

The quantity of gas flared during 2005, both onshore and offshore, rose by 160,955 tonnes to 1,617,140 tonnes hydrocarbons. 2005 flaring associated CO2 emissions were compensated by the overall reduction of CO2 totalling in excess of 1 million tonnes.

UKCS Flaring and Venting Levels 2001-2005

Atmospheric Emissions – Supplementary Statistics and Commentary

For more information, see the Supplementary Statistics Section.