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LCQ9: Emission reduction measures of franchised buses

     Following is a question by the Hon Jeffrey Lam Kin-fung and a written reply by the Secretary for the Environment, Mr Edward Yau, in the Legislative Council today (December 14):


     In his 2010-2011 Policy Address, the Chief Executive proposed to retrofit the Euro II and Euro III buses of franchised bus companies with catalytic reduction devices to meet Euro IV nitrogen oxide emission standards, and recommended the Government to fund the full cost of procuring six hybrid buses for use by franchised bus companies along the busy corridors in Hong Kong to test their operational efficiency. In this connection, will the Government inform this Council:

(a) whether it knows the respective numbers of Euro II and Euro III buses in the existing vehicle fleets of franchised bus companies in Hong Kong, and the number of buses already retrofitted with catalytic reduction devices;

(b) whether it has assessed the costs of retrofitting all the Euro II and Euro III buses currently in use with catalytic reduction devices; if it has, of the details, and the time required to complete retrofitting all such buses; if not, the reasons for that; and

(c) whether it knows the latest progress of the tests on hybrid buses; whether it has assessed when the tests will be completed; if it has, of the details; if not, the reasons for that?



     Nitrogen oxides (NOx) emitted by franchised buses are one of the main reasons causing the exceedance of the Air Pollution Index at roadside. At present, over 60% of franchised buses are Euro II and Euro III vehicles which will only be completely replaced by 2019 and 2026 respectively. Since they are still in operation on the roads, if their emissions could be reduced as soon as possible, it would help improve the roadside air quality.

     In some places in Europe, such as London and Belgium, they have retrofitted some of their buses with selective catalytic reduction (SCR) devices which reduce NOx emissions by about 60%. However, most public buses in these European cities are single-deckers whilst the majority of the franchised buses in Hong Kong are double-deckers. Besides, the high operation frequency and hilly terrains in Hong Kong all cause a relative increase in the engine load of local buses. Air conditioning is also required during hot summer time. Therefore, we have to conduct a trial to retrofit Euro II and Euro III buses with SCR devices to assess the technical feasibility and its effectiveness in emission reduction. If the Euro II and Euro III buses which were already equipped with diesel particulate filters (DPF) are retrofitted with SCR devices, their emission performance could be upgraded to Euro IV or Euro V level.

     Our response to the Hon Jeffrey Lam Kin-fung's questions is as follows:

(a) and (b) As at late September 2011, the franchised bus companies owned a total of 3 906 Euro II or Euro III buses. The respective number of these buses owned by the franchised bus companies is tabulated at the Annex.

     We have retrofitted three buses (comprising two Euro II and one Euro III buses) with SCR devices for trial in September 2011.  We are now retrofitting the other three buses (also comprising two Euro II and one Euro III buses) for trial, and we expect the retrofit to be completed in February 2012. We shall review the initial results after the first six months of the trial to ascertain as soon as possible the feasibility of retrofitting Euro II and Euro III buses with SCR devices on a large-scale and their effectiveness in reducing air pollutants. Subject to satisfactory trial results, the Government will fully subsidise the bus companies to retrofit Euro II and Euro III buses with SCR devices.

     These six buses for trial involve three major bus models, representing about 1 800 Euro II and 450 Euro III buses. We have also started to look into the feasibility of retrofitting the other bus models with SCR devices with a view to launching a trial for these buses as soon as possible.

     Given that some Euro II buses will retire in the next few years, we estimate that at the most about 3 700 Euro II and Euro III franchised buses would be retrofitted with SCR devices. Based on preliminary information provided by suppliers, the cost of large-scale retrofit of Euro II and Euro III franchised buses with SCR devices is estimated to be about $150,000 per bus. If all 3 700 buses were to be retrofitted with SCR devices, the total retrofit cost would be about $555 million.

     The time required for retrofitting all suitable buses with SCR devices depends on the number of such buses and the actual timetable for retrofit to be drawn up by the bus companies. Nevertheless, we aim to roll out the large-scale retrofit as soon as possible once the success of the trial is confirmed.

(c) As for the hybrid bus trial, the franchised bus companies are procuring the buses. Allowing the time required for production and delivery, we expect that the hybrid bus trial in Hong Kong could commence in 2013 for a period of two years.

Ends/Wednesday, December 14, 2011
Issued at HKT 12:17


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