Basically, by making use of the hydraulic pressure and flow of raw water in the aqueducts, electrical power can be generated through a set of turbine generators. By means of power converters and transformers, electricity would be generated by the water turbine generators, which will then be connected to the electricity supply grid of the Water Treatment Works (WTW) to meet part of its power demand and hence reduce carbon emissions as well as the expenditure on electricity. The actual amount of electricity generated will depend on a number of factors, such as water levels in reservoir, actual output of water treatment works and downtime of hydropower facilities due to maintenance and repair etc. It also enhances the stability and reliability of the operational facilities of the water treatment works.
The hydropower system at Tuen Mun WTW is an important RE project for the Water Supplies Department (WSD) and it is the first of its kind in Hong Kong. Designed and implemented by the Water Supplies Department, this innovative and environmental-friendly renewable energy project is a pioneer in the world to construct 500kW hydropower facilities at a water treatment works.
Tuen Mun Water Treatment Works
The hydropower project in Tuen Mun is carried out in two phases. The first phase and the second phase of the works have been completed successfully in May 2013 and February 2017 respectively. We estimate that the hydropower system can generate up to about 3 million kWh of electricity annually (equivalent to the potential reduction of about 2000 tonnes of carbon dioxide emissions each year from burning fossil fuels by the power company).
After the successful commissioning of the hydropower plant at Tuen Mun WTW, Sha Tin WTW was selected as the second location for installing a new hydropower plant. A 65-kW hydropower system has been commissioned in Sha Tin WTW in late 2019 and the generated electricity was transferred to the electrical power system for supporting the water treatment plant operation. We estimate that the hydropower system can generate up to about 360 thousand kWh of electricity annually (equivalent to the potential reduction of about 290 tonnes of carbon dioxide emissions each year from burning fossil fuels by the power company).
Hydropower Plant at Sha Tin Water Treatment Works
Not only does the successful commissioning of the hydropower system in Tuen Mun and Sha Tin signify our continual effort to employ renewable energy in waterworks installations, but also provides the industry with a useful instance of similar applications. With the valuable experience gained in this innovative project, we are going to install similar hydropower systems at the Ma On Shan WTW. The installation works at Ma On Shan are expected to be completed by 2022. In addition, we will explore other appropriate locations for installation of hydropower system so as to continue to strive for a better living environment for Hong Kong.