Sulphur Dioxide (SO₂) Emissions

The level of sulphur dioxide (SO₂) emissions from our operations is largely a function of coal-fired generation and depends on various factors, including the amount of fuel consumed, fuel sulphur content and the use of emission control technologies. SO₂, along with nitrogen oxides, can contribute to acidification of the atmosphere and soils.

SO₂ emissions up 3%

In 2004, our company-wide SO₂ emissions increased three per cent to 59,400 tonnes, from 57,500 tonnes the previous year. Although we shut down one unit at Wabamun, we continued to produce high levels of production from our coal plants. This resulted in our company-wide SO₂ emissions staying largely the same over the 2003 to 2004 period.

Our SO₂ emission intensity, however, continued to improve, due mostly to SO₂ scrubbers (emission control equipment) and lower sulphur coal blends at our Centralia coal plant. At year-end, we reported 1.26 kilograms of SO₂ per megawatt hour, which was consistent with our 2003 performance.

SO₂ allowance trading

Under the U.S. Acid Rain Program, utilities participate in a market-based allowance trading system. The system allows utilities to adopt the most cost-effective strategies to lower SO₂ emissions at units in their power systems. Power companies that reduce their emissions below the number of allowances they hold may sell them to other utilities on the open market or bank them to cover emissions in future years.

Because of our flue gas desulphurization plant in Centralia, installed in 2002, we continue to get significant SO₂ reductions at the coal plant. This has enabled our company to sell emission reduction allowances to other power companies under the program. In 2004, we had our most successful year yet in the allowance market, selling 4,990 tonnes of emission reduction allowances.