The technical assessment of desalinated seawater will be conducted early next year, says Financial Secretary John Tsang Chun- wah.
The assessment will include the desalination process - the process of extracting freshwater from seawater - and the intake of seawater.
Writing in his personal blog, Tsang said that Hong Kong lacks freshwater resources and desalinated seawater may become an important water resource in future.
The desalination plant in Tseung Kwan O will open in 2020 at the earliest. The plant will have an output capacity of 50 million cubic meters per annum, with provisions for future expansion to 90 million.
Based on the projected population of about 7.6 million in 2020, the plant will meet about 5 per cent of total demand by that time.
Tsang said extreme weather is becoming more frequent due to climate change.
Besides affecting the local catchment, it also affects the water sourced from Dongjiang that supplies 70 to 80 per cent of Hong Kong’s water. He said this water source is of great importance in the Greater Pearl River Delta as it supplies other cities in Guangdong including Shenzhen and Dongguan.
These cities make increasing demands on Dongjiang water.
“Hong Kong as a member in the economic zone in the Greater Pearl River Delta should not be overreliant on water from the Dongjiang, but should bear the responsibility to explore other new water sources, to prepare for the challenges of water supply in the future.”
Tsang said the Water Supplies Department has been monitoring the development of reverse osmosis - a new technology to remove salt from seawater.
In 2007 the department confirmed the feasibility of using this technology to produce water that reaches drinking water standards of the World Health Organization.
He said the department has reserved a 10-hectare site in Tseung Kwan O to build a desalination plant.
In 2012, the government started to study the cost- effectiveness and the feasibility of water transmission facilities’ construction as well as the evaluation of the construction such as the impact to the environment, transportation and drainage.
The desalination technology has developed quickly so the cost to produce water has declined from HK$35 in the 1970s to HK$12 per cubic meter at present.
Although it is still a bit more expensive than other water sources, it is still acceptable, he said.
