Desalination .
Established high/moderate development potential
Overview.
Desalination is becoming an increasingly important component of Southeast Asia’s water security strategy as coastal cities, small islands, and industrial centres face growing pressure from rapid urbanisation, saltwater intrusion, and climate change. Although the region holds only a small share of global desalination capacity, dependence on seawater reverse osmosis (SWRO) is increasing as governments seek reliable, drought-resilient water supplies that can complement traditional freshwater sources. The sector remains energy-intensive and costly, and expansion must carefully manage environmental impacts, infrastructure needs, and the push for more efficient and circular approaches.
Across ASEAN, desalination uptake varies widely, reflecting differences in geography, infrastructure capability, and investment readiness. Singapore has developed some of the region’s most advanced seawater reverse osmosis infrastructure and continues to pursue efficiency gains, dual mode plants, and underground siting options to optimise land use and strengthen resilience. The Philippines, Indonesia, Thailand, and Malaysia are expanding small to large-scale systems through public-private partnerships and community-level installations to address persistent freshwater shortages and the vulnerabilities of island systems. Technological progress, including improved membranes, energy recovery devices, digital twins for operations, and more effective intake and diffuser designs, is helping to reduce environmental footprints and operating costs. However, uneven financing, dependence on energy supply, and limited governance capacity still constrain wider adoption.
Within the broader sustainability and governance landscape, desalination intersects with water resource management, coastal communities, tourism, industrial development, and renewable energy systems because it depends on coastal space, requires energy-intensive processes, and can affect marine and coastal environments. These cross-sector dynamics influence environmental outcomes, service reliability, and long-term resilience, while supporting circular economy goals through more sustainable membrane production, longer membrane lifecycles, reduced waste generation, and emerging pathways for recycling and reuse. Together, these shifts can help desalination contribute to climate-resilient, low-impact water security across ASEAN.
Explore how Desalination is positioned for each of the
Blue Economy Capitals.
Financial Capital.
Financial Capital.
Financial investment in desalination across ASEAN is constrained by the sector’s high upfront capital expenditure (Capex) and the material exposure of reverse osmosis (RO) assets to electricity-price volatility, because energy consumption is a dominant driver of operating cost and project economics (Drouiche, 2026; Feo‑García et al., 2024; Montano et al., 2021; Wenner & Feo, 1995). These factors can reduce bankability and slow scaling through PPPs, even as water-security requirements continue to grow (Greer et al., 2021). In the Philippines, Metro Pacific Water’s PHP 5.5 billion Metro Iloilo Desalination Facility illustrates how sponsors and local governments are using early “flagship” projects to prove commercial viability and build replicable delivery and financing structures for urban drought-proofing (Lena, 2025; Romero, 2025). Consequently, while baseline financing is generally available in many markets, near-term emphasis remains on demonstrating bankability and mitigating power-price risk (including via contracting and risk-allocation tools) before more value-added, integrated desalination-and-reuse models can be financed at scale (GI Hub, 2019.; Feo‑García et al., 2024).
For example, Keppel Marina East is financed as a PPP concession in which PUB contributes land, enabling infrastructure and regulatory/technical support and ultimately owns the plant and water-supply rights (and pays for seawater supply), while Keppel finances and bears responsibility for design–build, construction capex, and 25-year O&M/disposal costs, with both parties sharing upgrade costs subject to independent dispute resolution (ADB, 2023).
Investment pipelines for desalination and water reuse across Asia are strengthening as water‑security pressures intensify and decision‑makers increasingly consider non‑traditional supply options in long‑term planning (World Bank, 2022; Shannon et al., 2008). In Indonesia, evidence from applied research and field studies points to growing deployment interest in reverse osmosis, including seawater RO on small islands and RO-based concepts for urban water supply that is supported by RO’s maturity, energy efficiency, and modular scalability (Savitri et al., 2024; Pratiwi & Herdiansyah, 2018; Liu et al., 2024). Complementing this, techno-economic work in Bali indicates the practicality of small-scale brackish water RO solutions under local cost and demand conditions, illustrating how tourism-driven demand and groundwater constraints can create investable niches for membrane desalination (Widiasa & Yoshi, 2016; World Bank, 2022). In Vietnam, multiyear growth potential is supported by both on the ground pilots and peer-reviewed operational evidence that nanofiltration/RO configurations can enable industrial wastewater reuse and high-quality water recovery, expanding the addressable space for PPP and blended/concessional structures when aligned with efficiency and affordability considerations (UNDP, 2025; Ho et al., 2022). Across the region, enabling guidance on PPP policy readiness, risk allocation, and project preparation, including dedicated desalination risk matrices, continues to evolve, strengthening bankability and the case for scaled private participation in desalination and reuse assets (ESCAP, 2017; GI Hub, 2019; Jardin Legal, 2026).
Blue finance is becoming increasingly material to desalination investment, as standardised frameworks for use of proceeds eligibility and impact reporting can lower structuring and disclosure friction for long tenor water assets (IFC, 2025; ICMA, 2023). These features are relevant for capital-intensive infrastructure such as desalination. The Philippines provides an operational precedent through BDO’s blue bond of up to US$100 million anchored by IFC, demonstrating how blue labelled financing structures can mobilise capital for water security infrastructure, including desalination and related supply solutions, when eligibility criteria and reporting requirements are clearly defined and aligned with recognised market principles (IFC, 2022; BDO, 2022).
Physical Capital.
Physical Capital.
The desalination footprint across ASEAN is expanding in both scale and configuration, with Singapore continuing to anchor the region’s installed base and to demonstrate increasingly land-efficient, climate-resilient plant concepts. Singapore currently operates five desalination facilities located across Tuas, Jurong Island, and Marina East, including the Keppel Marina East Desalination Plant, which is designed for dual mode operation and incorporates substantial below ground treatment works to conserve surface land uses (PUB, 2024). Building on these precedents, PUB has launched a feasibility study for a potential sixth desalination facility that will evaluate a dual mode configuration and compact design options, including deeper basements and potentially underground construction, to reduce site footprint while strengthening weather resilience (CNA, 2025; Qing, 2025).
Utility-scale development is also advancing in the Philippines. In Metro Iloilo, SUEZ, JEMCO, and Metro Pacific Water have commenced construction of a seawater reverse osmosis plant with more than 97% of production intended for potable supply and the remainder for demineralised water to support an adjacent power plant (SUEZ, 2025; PR Newswire, 2025). The project emphasises pretreatment robustness under variable coastal water quality. Beyond flagship projects, evidence from Indonesia points to broad uptake of small and community-scale RO desalination, especially in very small island settings where conventional storage and freshwater infrastructure are constrained. Field research on SWRO applications on Indonesian small islands documents government-commissioned systems and shows that while desalination can materially improve clean water access, long-term performance often depends on practical governance and operations and maintenance capacity, including repair lead times and institutional coordination (Savitri et al., 2024). Complementary techno-economic work in the Indonesian context similarly characterises RO desalination as frequently implemented at small scale, with cost and viability strongly influenced by electricity tariffs, financing assumptions, and local regulatory parameters, reinforcing the need to couple deployment with sustainable O&M models and financeable tariff structures (Yoshi & Widiasa, 2016; Widiasa & Yoshi, 2016).
At the technology level, the scholarly literature consistently identifies reductions in seawater RO specific energy consumption as being driven by improvements in membrane permeability and module hydraulics alongside higher efficiency pumps and energy recovery devices, which remain among the most influential levers for lowering operating costs and emissions intensity (Schunke et al., 2020; Karabelas et al., 2017). In parallel, research on hybrid configurations suggests additional energy and cost improvements may be achievable where enabling conditions exist, for example by integrating RO with salinity gradient energy recovery or by coupling RO with waste heat assisted processes, supporting better levelised cost and environmental performance for future ASEAN deployments that can leverage co location and heat or resource synergies (Tsai et al., 2022; Aumesquet Carreto et al., 2022). For broader plant-level context on low-energy developments and future efficiency pathways in SWRO, open access synthesis work also consolidates evidence on energy consumption drivers and technology trajectories relevant to large-scale implementation planning (Hong et al., 2023; Schunke et al., 2020).
Human Capital.
Human Capital.
Operating next-generation desalination in ASEAN requires cross-disciplinary skills across membrane science, process control, marine ecology, and data analytics. A concrete illustration is Malaysia’s digital twin at the Semenyih 2 water treatment facility which produces about 100 million litres per day and applies real-time optimisation of energy and chemicals that can transfer directly to seawater reverse osmosis operations (Smart Water Magazine, 2025; Schneider Electric, 2025). Regional collaboration through UNESCO’s Ocean Decade is expanding ocean literacy and technical exchange, although access remains concentrated in major hubs (IOC UNESCO, 2024; IOC WESTPAC, 2024). Inequalities persist for marginalised and remote communities, and the Philippines’ push for modular desalination underlines both the need and the opportunity to build local competencies (Domingo, 2024). Environmental reviews emphasise stronger capacity in intake design, brine dispersion modelling, and ecological monitoring to sustain public confidence, and recent guidance and tools provide practical methods to do so (American Water Works Association, 2024; Porto Pereira et al., 2024).
Basic systems for desalination, relevant education and training are taking shape and supporting local workforce development. In Singapore, the Singapore Water Association runs classroom masterclasses on membrane technologies and digital topics at PUB’s Singapore Water Exchange, building practitioner skills that translate into operations and maintenance and asset care (Singapore Water Association, 2024, 2025). PUB’s portfolio of five large reverse osmosis seawater plants provides a strong operational base for applied learning and skills transfer (PUB, 2024). Outside metropolitan centres, hands on training with the Philippine Marine Combat Engineering Battalion is developing practical competence for coastal and austere environments, while new municipal seawater reverse osmosis investments such as the 65 to 66.5 million litres per day Iloilo project are creating local upskilling pathways in plant operations, safety, and environmental management (Dreibund Corporation, 2024; Philippine News Agency, 2024; SUEZ, 2025).
Several ASEAN members are moving toward dedicated and well-funded programs for sector-specific education, training, and workforce upskilling with mechanisms to share learning and harmonise standards. The Semenyih 2 digital twin demonstrates the data-driven operations, predictive maintenance, and process control skill sets that desalination teams will increasingly require (Smart Water Magazine, 2025; Schneider Electric, 2025). Regionally, the ASEAN Blue Economy Framework embeds inclusivity and sustainability as guiding principles for capacity building and knowledge exchange, which can anchor equity initiatives that reduce participation gaps across gender and community lines (ASEAN, 2023). Complementary efforts such as UNDP’s Blue Economy initiatives is strengthening finance, research networks, and practitioner communities around adjacent skills and standards on freshwater resources (UNDP, 2025).
Social Capital.
Social Capital.
Governance for desalination in the ASEAN region remains uneven, but momentum is building toward clearer and more consistent practice through regionally coherent standards that still allow flexibility for local conditions. Singapore’s current feasibility work on a sixth plant that could operate in dual mode and be sited underground illustrates how adaptive regulation can expand options in land-scarce coastal cities, offering a concrete reference for regional guidance (CNA, 2025; Qing, 2025; PUB, 2025). Translating such lessons into a Southeast Asia desalination code that specifies expectations for intake velocities, diffuser design, baseline marine surveys, and post-commissioning audits would align governance with established science on brine management and mixing zones, supporting marine protection and transparent monitoring (Omerspahic et al., 2022; US EPA, 2006; Jirka et al., 1996).
Institutional coordination is strengthening, with Singapore’s cross-agency process on siting, environmental impact assessment, and discharge offering a model for shortening delivery and reducing design risk (Khemka & Eberhard, 2025; Qing, 2025; PUB, 2025). Operations are moving toward standardised performance reporting and digital oversight, as utilities in the region pilot digital twins and publish key indicators such as energy per cubic meter, membrane life, chemical intensity, and downtime, supporting benchmarking and investor confidence (Water & Wastewater Asia, 2025; Smart Water Magazine, 2025; Bam et al., 2025; Cuba et al., 2025).
Social capital is advancing through practices that emphasise fairness, transparency, and visible environmental stewardship, which strengthens community acceptance and cross-jurisdictional trust. Communications around the new desalination project in Iloilo stress reliable drinking water during drought and support for local development, positioning the investment as a model for other water-stressed islands and building durable buy-in from leaders and households (BusinessMirror, 2025; Lena, 2025). Environmental briefings and regulatory practice point to proactive mitigation and open data, for example publicly sharing salinity and dispersion metrics at the mixing zone using accepted methods, so that potential opposition becomes informed oversight and co-creation of solutions, reinforcing inclusive and participatory governance (UNEP, 2002; US EPA, 2026).
Natural Capital.
Natural Capital.
Across the ASEAN region, the natural capital footprint of desalination is still managed unevenly and ecological risks remain material. The most visible pressure points are the intake, where impingement and entrainment can harm marine life, and the outfall, where dense brine elevates local salinity, changes water chemistry, and affects sediments. Empirical and modelling studies document these effects and recommend stronger dispersion modelling and continuous long-term monitoring to protect coastal ecosystems (Omerspahic et al., 2022; Shaghaghi et al., 2024; Aljohani et al., 2022). Early measures such as subsurface or low velocity screened intakes and improved diffuser design are being introduced to lower biological impacts and enhance mixing, yet adoption is inconsistent across projects and jurisdictions and many monitoring programs are still reactive rather than systematic (Roberts et al., 2019).
More structured practices are appearing in leading projects that pair environmental safeguards with fit-for-purpose monitoring and circular approaches to brine management. Brine valorisation pathways and mineral recovery, including magnesium and multi mineral recovery trains, are advancing and can reduce disposal burdens while creating value, and reviews of zero or minimal liquid discharge options highlight how integrated recovery can align desalination with nature positive outcomes when supported by shared accountability and regional guidance (Fontana et al., 2022; Ojo & Oludolapo, 2025; Tong et al., 2025).
On the environmental front, recent syntheses and modelling advances offer reference methods for brine management and monitoring and help regulators and operators converge on transparent science-based practice (Prabakar et al., 2025; Pereira et al., 2024).
Assessment of Capacity for Growth
Assessment of Capacity for Growth
MODERATE
Across coastal Southeast Asia, seawater reverse osmosis is increasingly being incorporated into strategic water supply portfolios rather than treated as a niche or emergency option (Asian Development Bank, 2025). Singapore and the Philippines take the lead in this project. In Singapore, the national water agency has launched a feasibility study for a potential new desalination plant that would examine a dual mode configuration able to treat either seawater or freshwater and would also test innovative space-efficient design options, including deeper basements and higher multi-storey layouts (PUB, 2025; Qing, 2025). The Metro Iloilo project in the Philippines illustrates a utility-scale model and an implementation pathway framed around addressing drought and seasonal variability (SUEZ, 2025; Lena, 2025). Policy can accelerate responsible scaling in Indonesia and Viet Nam by combining standardised procurement with clear public-private partnership risk allocation, especially for energy price exposure, demand risk, and financial market risks that can affect bankability (Global Infrastructure Hub, n.d.; World Bank, n.d.; Vietnam Investment Review, 2025).
Environmental safeguards must be enforceable and measurable, particularly for seawater intake and brine discharge. Technical literature emphasises intake designs that minimise impingement and entrainment by controlling intake velocities and using appropriate screening approaches, including passive screens where suitable (Missimer et al., 2015); and numerical studies reinforce that intake velocity is a key driver of biological impacts and should be an explicit design criterion (Chie & Wahab, 2020). For brine management, diffuser design and compliance planning should be grounded in near-field mixing behaviour, defined mixing zones, and dispersion modelling, consistent with specialist guidance on desalination brine diffusers (Roberts et al., 2019).
Desalination is not a standalone fix. Regional water security guidance frames resilience as an integrated portfolio that combines demand management, reuse, groundwater stewardship, ecosystem protection, and well-governed finance and delivery systems, with desalination serving as one weather-resilient pillar within that broader approach (Asian Development Bank, 2025). With Singapore’s innovation pathway for compact and flexible plants (PUB, 2025), the Philippines’ utility scale build out, and growing interest across Indonesia and Viet Nam supported by maturing PPP frameworks, ASEAN has the ingredients to scale desalination responsibly provided that expansion is matched with transparent performance reporting, enforceable marine safeguards, and sustained progress on energy efficiency and decarbonisation pathways.
