LCQ13 : Measures adopted by Government Offices to save electricity

Following is a question by the Hon Audrey Eu and a written reply by the Secretary for the Environment, Transport and Works, Dr Sarah Liao, at the Legislative Council meeting today (December 14) :


According to the Government's reply to a written question last month, there were huge differences in the annual average per-square-metre amount of electricity consumed last year by the Government Offices in various districts.  For example, the per-square-metre amount of electricity consumed by the Tuen Mun Government Offices was more than nine times that of the Canton Road Government Offices.  In this connection, will the Government inform this Council of:

(a)  the reasons for the huge differences in the per-square-metre amount of electricity consumed by various Government Offices;

(b)  the gross floor areas of the offices in each Government Office and the number of staff accommodated therein; and

(c)  the measures adopted by various Government Offices to save electricity?


Madam President,

The energy consumption per unit area may be affected by many factors. It is not always appropriate to compare the energy consumption per unit area of two buildings. To monitor the energy saving performance, it is usually better to analyze the energy consumption figures of the same buildings in different periods, provided that there are no major activity changes in the buildings across the periods.

Major factors affecting the energy consumption per unit area include -

* number of staff and visitors flow - more staff members accommodated in a building and more people visiting the building (e.g. public facilities in the building) usually increase the energy consumption per unit area;

* computer usage and special equipment within the buildings - a higher intensity of computers and network equipment increases the per-square-metre consumption. Buildings accommodating offices that require special energy demanding equipment often consume more energy per unit area;

* level of usage - the operating hours of the offices accommodated in a building and occupancy rate of the building obviously affect the energy consumption in per-square-meter terms;

* mix of usage - different buildings may have different mix of usage, resulting in different energy consumption per unit area. Some are pure offices buildings. Some may have large conference facilities. Others may contain storage areas, laboratories and workshops;

* building location and orientation - a building near to the seashore may be able to use seawater-cooled air conditioning system, which is more energy efficient. A building tends to consume more energy if more windows are facing south or subject to direct sunlight;

* level of building services provision - buildings designed and built in earlier years tend to be less well provided with building services facilities. They usually consume less energy per unit area; and

* ratio of internal floor area to gross floor area - the ratio depends on the design of individual buildings. A building with a higher ratio of internal floor area tends to use more energy per unit of gross floor area.

The Canton Road Government Offices are in the process of being vacated for construction of a railway, hence the unusually low energy consumption rate.

 The gross floor area and the number of staff accommodated in the major government offices buildings are set out in Annex.

Over the years, EMSD has carried out around 230 energy audits on major public buildings to identify and implement energy saving measures. Energy efficient florescence tubes (T8 and T5) and electronic ballasts have replaced less efficient lighting devices in virtually all government premises. Whenever technically feasible, energy efficient water-cooled air conditioning systems are gradually replacing less efficient air-cooled ones. Variable speed drives are also widely adopted in air-conditioning plants to reduce energy consumption under partially-loaded condition. Occupancy sensors and timer switches are also installed in some offices to automatically switch off lightings and air-conditioning when not in use.

Furthermore, departments have also been implementing energy conserving housekeeping measures, such as switching off lightings and computers when not in use, maintaining air-conditioning temperature at 25.5°C, switching off some lifts during off-peak hours.

End/Wednesday, December 14, 2005