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4B.1 BPPS Contribution

Since the BPPS is gas-fired gas turbine power plant, the SO₂ emission is very negligible in accordance with the BPPS EIA Study, Annex B (Source Emissions and Characteristics – Option 3). Therefore, in this Study, no SO₂ concentration attributable to BPPS is considered.

4B.2 CPPS Contribution

Short-term SO₂ Concentration

For the ASRs A3 to A8, the worst wind direction blowing from LNG Terminal to the ASRs is opposite to the worst wind direction blowing from CPPS to the ASRs, therefore, no short-term cumulative SO₂ concentration is anticipated at ASRs A3 to A8.

For ASRs A1 and A2 located at Sheung Pak Nai and Nim Wan, respectively, contribution from CPPS is likely to cause cumulative SO₂ impact with the LNG Terminal contribution.

The CPPS contribution assessed in the BPPS EIA Study is used in the following calculation.

In the BPPS EIA Study, no wind tunnel testing was performed at Sheung Pak Nai. However, Sheung Pak Nai (8 km) is located further away from CPPS than Nim Wan/Ha Pak Nai (i.e., 5.5 km) and the NO₂ concentration at Sheung Pak Nai should be lower than that at Nim Wan/Ha Pak Nai. Therefore, SO₂ concentrations predicted at Nim Wan/Ha Pak Nai are used as worst case SO₂ concentration at Sheung Pak Nai.

The worst wind direction of CPA and CPB to Nim Wan/Ha Pak Nai is about 195°. However, no wind tunnel testing for SO₂ was performed at such wind angle and hence the NO_x concentrations in the Annex H, Table H.1b of the BPPS EIA Study, (maximum hourly NO_x concentration at 8 ms^-1 are 118.3 µgm^-3 and 91.7 µgm^-3, contributed from CPA and CPB, respectively), will be adjusted to SO₂ concentrations by using the ratio of existing SO₂ licensed limit (i.e., 2,100 mgm^-3) and NO_x concentrations in the BBPS EIA Study Annex B (Source Emissions and Characteristics, i.e., 1577 mgm^-3). Hence, the source SO₂ concentrations are both 133% of source NO_x concentrations for CPA and CPB and the SO₂ concentrations attributable to CPA and CPB are, therefore, 157 µgm^-3and 122 µgm^-3, respectively.

There is no flue gas desulphurization system (FGD) applied to the current CPA and CPB operation. For CPB, FGD will be installed to reduce SO₂ emission and about 89% of SO₂ concentration will be reduced at Nim Wan/Ha Pak Nai area in accordance with the EIA for Emission Control Project to CPPS “B” Units, Annex A, Table A.4. Therefore, 89% SO₂ reduction will be applied to the adjusted SO₂ concentration attributable to CPB. Therefore, maximum hourly SO₂ concentration attributable to CPB will be 122 µgm^-3 x (1-0.89) = 13 µgm^-3.

Therefore, total maximum hourly SO₂ concentration attributable to CPA and CPB is 157 + 13 = 170 µgm^-3.

Long-term SO₂ Concentration

The 2^nd daily and annual average SO₂ concentrations presented in the BPPS EIA Study, Part B, Table 6.2b had considered the contribution from CPPS (no contribution from BPPS as negligible SO₂ emissions due to gas-fired plant operation). Comparing the existing SO₂ licence limit of 2,100 mgm^-3 of both CPA and CPB and the source SO₂ concentrations in the BPPS EIA Study, Part B, Table 6.2b (1,635 mgm^-3 for CPA and 1,726 mgm^-3 for CPB), the 2^nd daily and annual average SO₂ concentrations in the BPPS EIA Study, Part B, Table 6.2b are adjusted by applying a factor of 1.28 ([1]) to reflect the current power station operation and the adjusted 2^nd daily and annual average SO₂ concentrations are summarized as below.

	Lung Kwu Tan	Ha Pak Nai
Worst wind speed adopted in Wind Tunnel Testing (m/s)	12	8
2^nd Highest Daily SO₂ Concentration	11% of AQO (39µgm^-3)	17 % of AQO (60 µgm^-3)
Annual SO₂ Concentration	1 % of AQO (0.8 µgm^-3)	1.9 % of AQO (1.5 µgm^-3)

Note:

(a) Reference to BPPS EIA Study, Part B, Table 6.2b and a factor of 1.28 is applied.

As the above long-term SO₂ concentrations are contributed from both CPA and CPB and hence the SO₂ emission from CPB will be adjusted by further reduced due to the implementation of the Emission Control Project to CPPS “B” Units.

Summary

A summary of adjusted short-term and long-term SO₂ concentrations are presented as below.

	Lung Kwu Tan	Nim Wan / Ha Pak Nai	Sheung Pak Nai ^(a)
Worst wind speed adopted in Wind Tunnel Testing (m/s)	12	8	8
Adjusted Maximum Hourly SO₂ Concentration	-	170 µgm^{-3 (b)} (CPPS ONLY)	170 µgm^{-3 (b)} (CPPS ONLY)
Adjusted 2^nd Highest Daily SO₂ Concentration (CPPS)	39 µgm^-3	60 µgm^-3	60 µgm^-3
Adjusted Annual SO₂ Concentration (CPPS)	0.8 µgm^-3	1.5 µgm^-3	1.5 µgm^-3
Note: (a) No wind tunnel testing was performed at Sheung Pak Nai in the BPPS EIA Study; the SO₂ concentrations predicted at Nim Wan/Ha Pak Nai is used as worst case assumption. (b) A total SO₂ concentrations of CPA and CPB contributions (i.e., 157 µgm^-3 + 13 µgm^-3 = 170 µgm^-3)

For the worst case assessment, the adjusted 2^nd highest daily and annual average SO₂ concentrations at Nim Wan/Ha Pak Nai (60 mgm^-3and 1.5 mgm^-3, respectively) will be adopted for the cumulative long-term impact assessment at all identified ASRs and for plotting the contours to assess the worst case cumulative SO₂ impacts.

Of note, in accordance with the indicative commencement programme in the Emission Control Project to CPPS “B” Units, the FGD will be operated in end of 2009 to 2011 which should be earlier than the LNG Terminal operation. Therefore, during the LNG Terminal operation, the 2^nd highest daily and annual average SO₂ concentration should be much lower based on the future SO₂ reduction programme at CPB.

Similar to short-term NO₂ contribution from CPPS, no contribution of SO₂ from CPPS to Nim Wan/Ha Pak Nai and Sheung Pak Nai areas at 232° (which is the same worst wind angle of LNG terminal to Nim Wan/Ha Pak Nai and Sheung Pak Nai areas. Therefore, the cumulative short-term SO₂ impact considering the SO₂ contribution from CPPS at 195° is a very worst case assessment in this study.

Therefore, the cumulative short-term and long-term SO₂ impact assessment in this Study will be the worst-case assessment.

([1]) The CPA source SO2 concentration, i.e., 1,635 mgm-3 is used for the adjustment to obtain a conservative factor.