SINGAPORE - The Republic's fifth desalination plant opened on Jurong Island on Sunday (April 17), boosting the nation's capacity to tap its surrounding sea for water sustainability.

Equipped with the latest proven water technologies, the new plant can produce up to 30 million gallons, or 137,000 cubic metres of water daily, the equivalent of 55 Olympic-size swimming pools, said national water agency PUB.

This amounts to up to 7 per cent of Singapore's daily water demand of about 430 million gallons.

Unlike the nation's first four desalination plants, only two to three people are needed to man this highly automated plant, making it the most manpower-efficient.

Desalination - the conversion of seawater to drinkable water - is the last of Singapore's four national taps, the others being imported water, local water catchments and Newater.

With water consumption expected to double by 2060, PUB had earlier said the plan is for weather-resilient sources Newater and desalination to meet up to 85 per cent of Singapore's future water demand.

Currently, more than half of local water consumption comes from water catchment areas and imported water, said Mr Ong Key Wee, PUB head of public-private partnership management office.

On Sunday, Deputy Prime Minister and Coordinating Minister for Economic Policies Heng Swee Keat officially launched the new desalination plant in conjunction with the start of the Singapore International Water Week.

The plant's unique integration with Tuas Power's Tembusu Multi-Utilities Complex makes it about 5 per cent more energy-efficient than conventional desalination plants, said Mr Heng.

Spanning more than 3.7ha, or about the size of five football fields, the plant receives seawater used to cool the complex - a utility plant supplying steam and electricity for chemical companies on Jurong Island - for processing into potable water.

Its sharing of seawater-intake and water-discharge facilities with the complex as well as power supply results in annual energy savings sufficient to power nearly 1,000 Housing Board households, said PUB.

Such energy savings will make seawater desalination - the most expensive way to produce water due to the energy required - much more palatable, noted PUB chief executive Ng Joo Hee.

Mr Jiang Hanbin, president and chief executive of Tuas Power, said: "Leveraging the complex's existing infrastructure for seawater intake, the synergies between desalination plant and the complex have enabled operations to save approximately 5,000 megawatt-hours per year."

The plant will operate as a joint venture company formed by the Tuas Power-ST Engineering consortium for a period of 25 years.

With Internet of Things technology, smart analytics will enable predictive maintenance of the plant to optimise productivity, monitoring of reverse osmosis and detection of membrane fouling in the plant's extensive network of pressure vessels.

While the plant was slated to begin operations in 2020, its opening was delayed by about two years owing to the manpower crunch caused by the Covid-19 pandemic.

Said Mr Heng: "The completion of the Jurong Island Desalination Plant... marks another key milestone in our water journey.

"This is the second desalination plant to start operation in the last two years."

In his speech, Mr Heng took stock of how Singapore has grown from rainfall-dependent sources - imported water and local water catchments - to adding weather-resilient sources Newater and desalination in the 2000s.

He noted that it took several decades for desalination to become cost-viable in Singapore, with the first large-scale desalination plant commencing operations in Tuas in 2005.

But Newater and desalination come with limitations, said Mr Heng, observing that they are more expensive and have a much higher carbon footprint, especially desalination.

As the nation strengthened the resilience of its water resources, the cost of water operations had grown from $500 million in 2000 to $1.3 billion by 2015.

Though seawater is limitless, extracting fresh water through desalination requires a lot of energy. Hence, desalination is relatively more expensive compared with other processes, said PUB's Mr Ong.

To lower the energy-intensive process of desalination, Singapore has been investing in research and development to reduce the energy take, said Mr Heng.

"For example, PUB will be building a desalination Integrated Validation Plant in Pasir Ris to trial promising technologies for implementation in full-scale desalination plants," he added.

When validated and scaled up, such technologies could potentially reduce the energy required to produce one cubic metre of desalinated water from 3.5 kilowatt hours (kWh) to less than 2kWh by 2025, said Mr Heng.