Low-Energy Desalination on the Horizon
Singapore is seeking innovators to develop low-energy desalination technologies.
Around the world, desalination has become necessary to ensure water security for cities. However, one of the main barriers to desalination becoming a mainstream, alternative source of water is its higher water costs, which are influenced by energy consumption (represents 50–60% of total costs).
Rising water-energy nexus pressures will pose a further challenge to desalination as water withdrawals for the energy sector is projected to increase by less than 2% to reach over 400 billion m3 by 2040 while at the same time the amount of energy used by the water sector is projected to double with the largest increase coming from desalination.
Singapore seeking energy-efficient desalination solutions
Currently, Singapore uses around 430 million gallons of water per day. By 2060, the water demand is projected to double, with seawater desalination expected to become a major source of the city-state’s water by then. Recognizing the country’s growing dependency on energy-intensive seawater desalination, Singapore’s Public Utilities Board (PUB) has for a considerable amount of time focused on seeking energy efficiency solutions for desalination.
The current state-of-the-art seawater desalination plant consumes around 3.5 kWh/m3 at about 50% recovery. Through R&D, the short-term goal is to reduce energy consumption for seawater desalination to less than 2 kWh/m3 at the system level. To achieve this, there needs to be considerable research directed towards improving the main desalting step through innovative solutions as well as increasing energy recovery. With pre- and post-treatment for seawater desalination typically consuming about 1 kWh/m3, PUB has identified this as an area that R&D needs to focus on.
To find innovative ways of reducing the water-energy nexus pressures of desalination, PUB has launched a Request for Proposal to invite researchers and industries to develop low-energy and low-chemical solutions for pretreatment processes and post-treatment processes for seawater desalination:
- Pretreatment: PUB is seeking solutions that can enhance the effectiveness and/or efficiency of pre-treatment for seawater desalination. The technologies proposed shall show how it uses less energy and/or less chemicals as compared to the standard treatment train
- Post-treatment: PUB is soliciting solutions that can enhance the effectiveness and/or efficiency of post-treatment (particularly boron removal) for seawater desalination. The technologies proposed shall show how it uses less energy and/or less chemicals compared to the standard treatment train
Conclusion
Low-energy desalination is key to achieving water and energy security.