To tackle the impacts of climate change, departments under the Development Bureau (DEVB) have been proactively implementing a host of energy-saving measures, including those to enhance energy efficiency in the operational processes and to explore the application of renewable energy in various facilities.  Recently, I have invited the Secretary for the Environment, Mr WONG Kam-sing, for a visit together to the Water Supplies Department’s (WSD) floating photovoltaic (FPV) system at Plover Cove Reservoir to better understand its effectiveness in environmental protection and energy saving.  I would like to share our visit with you.

The WSD is exploring the potential of installing FPV systems over the local reservoirs to further develop the use of renewable energy.  To test the system’s feasibility and to assess its efficiency, the WSD has first piloted projects at Shek Pik Reservoir and Plover Cove Reservoir, each installed with a set of 352 solar photovoltaic panels.  The FPV system at Plover Cove has been in operation for about six months while the one at Shek Pik for more than a year.  On the day of our visit, we travelled by boat arranged by the WSD to the east side of the reservoir near the dam and looked at the solar panels installed on the water surface up-close.  The rectangular solar panels are laid out neatly in a grid and present a beautiful picture together with the smooth water surface of the reservoir, showcasing the harmonious integration of natural scenery and green technologies.

The many benefits of installing FPV systems over reservoirs

According to the Assistant Electrical Engineer of the WSD, Mr LEUNG Chi-fung, installing FPV systems on the water surface can make good use of the water properties, which can naturally cool the solar panels to enhance the overall efficiency in electricity generation, while the solar panels can also cover the water surface to reduce water evaporation and protect our water resources.

At present, the electricity generated by the two systems has been used mainly by the WSD facilities near the reservoirs.  Each system is designed for a generation capacity of 100 kilowatts (kW).  It is anticipated that as much as 120 000 units of electricity can be generated annually, equivalent to the annual electricity consumption of 36 average households.  In addition, a total of 84 tonnes of carbon dioxide emissions will be reduced each year, which amounts to the planting of 420 trees.  These all demonstrate that the effective use of renewable energy is beginning to bear fruit.

The solar panels installed over the two reservoirs measure about 1 100 square metres each, covering only a very small area of the reservoir.  As all panels are made of anti-reflective glass, there will not be any significant impact on the surrounding environment, but will instead benefit the ecology.  We noticed that there are bird droppings on the panels.  Mr LEUNG said that the droppings are the “footprints” of birds on the panels, showing that artificial devices can blend well with nature and offer a man-made rest place for the birds.

Ensuring clean water supply

Apart from promoting environmental protection and energy saving, the WSD also attaches great importance to the water quality of reservoirs.  I learned that fish fry are regularly stocked into reservoirs to maintain ecological balance.  According to the Chemist of the WSD, Ms CHU Yik-fai, Sunny Rachel, the fish fry they stock include Big Head and Silver Carp, which will help eat algae in the water and can in turn control algal growth and maintain ecological balance.  The WSD also regularly collects water samples from different locations of the reservoirs for water quality tests, and carries out real-time monitoring of water quality with equipment to ensure the quality of reservoir water.

The largest solar farm in Hong Kong

Talking about solar power, I cannot but mention the Drainage Services Department (DSD) and the Electrical and Mechanical Services Department (EMSD).  The DSD operates over 300 flood protection and sewage treatment facilities which require massive amounts of energy each day.  To promote sustainable development and combat climate change, the department has been actively introducing elements of renewable energy and energy saving/emission reduction to new and existing plants.

At present, the solar farm at the Siu Ho Wan Sewage Treatment Works of the DSD is the largest of its kind in Hong Kong.  Comprising over 4 200 polycrystalline photovoltaic panels with an installed generation capacity of 1 100 kW, the solar farm can generate as much as 1.1 million units of electricity annually–roughly equivalent to the total annual electricity consumption of 230 households, thereby reducing carbon dioxide emissions by 770 tonnes each year.  The electricity generated by the solar farm will be fed to various facilities inside the plant, including screening facilities, a workshop, an administration building, an ultra-violet disinfection system and sludge treatment facilities.  Apart from achieving energy saving and emission reduction, the farm also helps save the electricity expenses of the sewage treatment works.

Active implementation of energy saving and emission reduction

Meanwhile, the EMSD has also been actively implementing a host of energy-saving and emission-reduction solutions in various government departments and the public sector, so as to reduce energy consumption and enhance energy efficiency.  Apart from the installation of a solar photovoltaic system at its headquarters building several years ago, the EMSD has been pushing for replacing ageing air-conditioning systems with energy-efficient ones; changing lighting systems to LED lighting; optimising the operation of chillers, etc. in government buildings, in order to achieve the target of reducing electricity consumption in government buildings by 5%.

Earlier, the EMSD and the Hospital Authority jointly introduced innovative energy-management projects by replacing the ageing air-conditioning units with magnetic bearing variable speed chillers in a number of hospitals.  As a consequence, an annual electricity consumption of more than 13 million kilowatt-hours has been saved.  The project received “the Regional Energy Project of the Year Award for the Asia-Pacific Region” from the Association of Energy Engineers.

To build a more liveable Hong Kong, apart from urban planning and design as well as the provision of infrastructure and transport support, the work on environmental protection is growing in importance.  The DEVB will continue to strengthen co-operation with the Environment Bureau and explore ways for the wider promotion of environmental protection and energy-saving measures towards building a green Hong Kong together.