Hong Kong Justifies $12/m3 Desalination Cost in Tseung Kwan O

The Hong Kong government has said that its planned 90 million m3/year desalination plant will cost more per unit of water than other plants in the region due to inflation and distribution and customer service costs.

The government plans to build a desalination plant in Tseung Kwan O which is expected to have a unit cost of $12/cubic metre – substantially higher than other planned facilities in the region.

In April 2011 Hyflux announced a 25-year water agreement for Singapore utility PUB’s second desalination facility, with a fixed price of $0.45 per m3 for the first year. Hong Kong’s planned Tseung Kwan O project will be the first desalination facility since the Lok On Pai site was decommissioned over 30 years ago.

Currently the majority of Hong Kong’s water (over 70%) comes from the Dongjiang river basin in Southern China. The rest comes from local catchments. Although an agreement is in place for the Dongjiang water supply, as the river flows through Guangdong, industrial demand for water is high in China.

In 2005 Hong Kong’s Water Supplies Department (WSD) conducted a successful pilot study on reverse osmosis (RO) desalination at Tuen Mun, followed by a second study at Ap Lei Chau.

Completed in 2007, pilot results suggested that the price of desalination in Hong Kong could be between $7.8 to $8.4/m3.

The difference in price has led the Hon. Claudia Mo, member of the Legislative Council, to ask why the price per unit of desalinated water has risen from between $7.8 to $8.4/m3 in 2007 to $12/m3 today.

In response, Paul Chan, secretary for development of Hong Kong, told the Legislative Council: “Seawater desalination using reverse osmosis technology is now an energy intensive process.”

He said: “The current estimated cost of seawater desalination of $12 per m3 is derived by adjusting the average of the above prices in 2006 (i.e. $8.2) upward by 18% [Note: This is based on the changes to the Consumer Price Index (A) in 2006-2012] to account for the inflation from 2006 to 2012, and add the distribution and customer services cost, which have not been calculated in the 2006 cost estimate.”

However, Chan added that with the “improvements in related technology”, that there could be room for a “downward adjustment in the energy consumption in the desalination process”.

The International Desalination Association (IDA) was quoted as saying that the unit cost for producing potable water by seawater desalination using RO technology varied by country and region, ranging from $9.4 to $22 per m3.

According to the WSD, the initial desalination plant will be able to produce 50 million m3/year and will eventually be expanded to 90 million m3/year.

Together with collected rainwater and 820 m3 of water from the Dongjiang river basin, this is expected to help Hong Kong meet its potable water demand by 2030.

WSD said the timetable for the facility will include: 2012-2014 – undertake planning and investigative study of Tseung Kwan O desalination plant and between 2015-2017 – invite tender for construction and seek funds from the Legislative Council. The date earmarked for construction is between 2018-2020.

The secretary for development concluded that alternative sources such as reclaimed water will be reviewed and another desalination plant could be developed “as necessary when the technology is proven”.