Carbon dioxide emissions
Thanks to reduced consumption of fuel oil and better plant efficiency, the CO₂ intensity decreased from 0.592tons/MWh to 0.582tons/MWh, an improvement of about 2% between FY06/07 and FY07/08. The overall plant efficiency improvement of about 0.85% in FY07/08 over FY06/07 is contributed mainly from the combined cycled power plants (CCPP) that run on natural gas. Looking ahead, we expect further improvements when the 800MW CCPP project starts in the first half of 2010 which would bring about a further 10% reduction in carbon dioxide emissions in the near future.

The indirect carbon emissions arising from our operations at the corporate headquarters can be found in Section 7.2(i)

Note The CO₂ intensity figures cover the power plant operations which are the major CO₂ emission contributor. It does not include indirect CO₂ emissions from the electricity that we buy from third parties.

Diagram 7.6: Reduction in carbon dioxide intensity emissions in FY06/07 and FY07/08

Sulphur dioxide emissions and mitigation initiatives
The fuel oil used in our power plant operations has a relatively high sulphur content which releases SO₂ into the atmosphere when burnt. Exposure to high levels of SO₂ can cause breathing problems, respiratory illnesses and cardiovascular disease. To mitigate these harmful effects, we burn fuel oils with no more than 2% sulphur content in them, which is within National Environment Authority (NEA) requirements.

The resulting SO₂ emissions go through a flue gas desulphurisation (FGD) unit which removes over 90% of toxic emissions. In FY07/08, there was a significant reduction in the SO₂ intensity of about 7% due mainly to the removal of SO₂ emissions by the FGD at the Stage 1 steam plants and the burning of lower sulphur content fuel oil in the remaining steam plants. We were able to maintain the high level of FGD efficiency in the period FY06/07 to FY07/08 by adopting a proactive maintenance regime and implementing a comprehensive monitoring programme for the FGD plant. An ISO 14001 objective is established to maintain SO₂ emission below 130ppm at the absorber outlet instead of the design value of 150ppm.

Diagram 7.7 : Reduction in sulphur dioxide intensity in FY07

Nitrogen dioxide
We are unable to report on our NO₂ emissions at this present moment because of the difficulties in measuring the actual amount of nitrogen dioxide from the boilers on a continuous basis. Moreover, there is also no flow meter to capture the total flow of flue gas in order for us to compute the total NO₂ emission. However, we have consistently kept the NO₂ levels below the regulatory limits set by the National Environment Agency of 700 mg/Nm³.

Ozone-depleting emissions
There were no ozone-depleting emissions from power plant operations. However, our office air-conditioning emitted insignificant amounts of hydrochlorofluorocarbons, of between 135kg and 158kg in FY07/08 and FY06/07 respectively.