Following is a question by the Hon Ho Chung-tai and an oral reply by the Secretary for the Environment, Transport and Works, Dr Sarah Liao, in the Legislative Council meeting today (March 19) :
Question:
With the use of solar-powered irrigation systems, vegetation on slopes in remote areas can grow with the necessary water supply and thus help to stabilize the slopes. In this connection, will the Government inform this Council of:
(a) the number of slopes in the territory on which the vegetation is suitable for watering by solar-powered irrigation systems, and the estimated expenditure on the installation of such systems for the slopes;
(b) the time required for installing a solar-powered irrigation system; and
(c) the life of battery banks for storing electricity produced by such systems?
Reply:
Madam President,
(a) The Civil Engineering Department is conducting a feasibility study on the use of solar-powered irrigation systems. If such systems prove to be technically feasible and cost-effective, we will consider installing them on suitable government slopes. According to our preliminary estimate, about 20 such slopes which are higher and without water supply are suitable for the use of solar-powered irrigation systems.
The Government's preliminary estimate for the expenditure on installing such a system on a slope is in the order of HK$300,000, about 80% of which is used for procuring the equipment. Part of the equipment, however, can be re-used. The life span of the entire system is 3 to 5 years during which the vegetation can grow steadily. After taking into account the maintenance cost for 3 to 5 years, each system is estimated to cost around HK$330,000. At this stage, the Government does not have any concrete plan to install solar-powered irrigation systems on slopes. Government departments will carefully consider the actual need for installing such systems on individual slopes so as to ensure that any such plans, if implemented, can deliver value for money.
(b) The Civil Engineering Department is conducting a site trial in Kau Shat Wan on Lantau Island to develop an irrigation system powered by solar panels. The time required for the design and installation of the system is about 9 months. Upon completion of the trial scheme and when the installation techniques have been mastered, it is likely that the time required for installing a solar-powered irrigation system can be reduced to around 4 to 6 months.
(c) The solar batteries used in the above study can store electricity for 3-days' consumption by the irrigation system. Therefore the system can still operate on overcast days. The life of a solar battery is generally 2 to 3 years.
End/Wednesday, March 19, 2003
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