Our Emissions Performance

We combust, flare and vent natural gas from our operations. This results in emissions of air pollutants including oxides of nitrogen, sulphur dioxide, volatile organic compounds, particulate matter and benzene.

Emissions of oxides of nitrogen remained relatively unchanged from 2007 to 2009.

Emissions of volatile organic compounds remained relatively unchanged from 2007 to 2009.

Sulphur Dioxide

Sulphur dioxide is produced when sour gas, which is natural gas containing hydrogen sulphide, is burned. In our Western Canada Gas operations, we burn sour gas in flare stacks as a waste gas. In 2009 we operated 15 facilities that reported sulphur dioxide emissions. Quantities of sulphur dioxide emissions are highly influenced by operating conditions and the concentration of hydrogen sulphide in the natural gas processed. The 129 percent increase in sulphur dioxide emissions from our operations between 2008 and 2009 is due to an increase in the concentration of sour gas produced from maturing fields and flared at two gas batteries.

10 facilities in 2007
12 in 2008,
15 in 2009

Particulate Matter

Particulate matter emissions from our operations are formed primarily when gas is burned in flare stacks and through the combustion of natural gas in equipment like engines and boilers. Particulate matter emissions are released from over 1,000 emission sources in our Western Canada Gas operations. Since 2007, there has been a steady decline in the amount of particulate matter we emit, a total reduction of 20 percent. This decline is due to a reduction in flaring. We reduced well-test flaring, as we drilled fewer wells (40 percent of the total reduction). We also reduced flaring at 14 facilities (60 percent of the reduction).

Benzene Reduction

Alberta, British Columbia and Saskatchewan have legislation that requires annual reporting on benzene emissions from glycol dehydrators. A dehydrator is a device used to remove water and water vapours from gas. Benzene emission limits vary depending on the installation date of the glycol dehydrator and the distance of the dehydrator to the nearest permanent residence or public facility.

We reduced the number of glycol dehydrators in our operation from 162 in 2007 to 120 in 2009, resulting in an eight percent decrease in total benzene emissions.

In late 2009 and into 2010, we purchased and implemented a new Dehydrator Emissions Management System that allows us to work closely with our engineering groups and field operations staff to improve our dehydrator emissions reporting. It also allows us to identify optimization opportunities.

We are also in the process of testing a new technology to reduce benzene emissions from our dehydrators. This technology uses the benzene that is normally vented as fuel in the glycol reboiler, thereby reducing benzene emissions, while also slightly reducing greenhouse gases. The design work for this project was initiated in 2009 and the unit has been purchased and will be installed in 2010.