They are largely produced from burning oil, coal and gas. TransAlta has pursued the deal as part of its strategy to reduce its greenhouse gas emissions to a net equivalent of zero by 2024. Though the company's plants will still produce gases, they will be offset by eliminating an equivalent amount of gases elsewhere through the Uganda deal and other planned projects. TransAlta operates power plants in Alberta and has holdings in the United States, Australia and New Zealand. The agreement is the type envisioned by the 1997 Kyoto Protocol, an international treaty for industrialized nations to reduce the amount of greenhouse gas emissions to pre-1990 levels by the year 2012.
Environmental groups question the validity of the strategy.
John Wellner of Pollution Probe said TransAlta generates much of its power by burning coal, which releases toxins that contribute to smog and acid rain.