Myth-busting water security & desalination: separating hype from reality

In 2024, global desalination capacity reached 128.5 million cubic meters per day across 22,757 operational plants, yet myths about this critical technology continue to distort investment decisions and policy frameworks (IDA 2025). The European Investment Bank committed €4.2 billion to water security infrastructure in 2024-2025, with desalination representing 31% of funded projects—up from just 12% five years prior. Meanwhile, the prevailing narrative that desalination is inherently unsustainable, prohibitively expensive, or technologically immature fails to account for transformative advances in energy efficiency, brine management, and renewable integration that have fundamentally altered the technology's environmental and economic calculus. Understanding what desalination can and cannot deliver—separated from both utopian promises and reflexive dismissal—is essential for investors, policymakers, and sustainability professionals navigating water security in an era of accelerating climate stress.

Why It Matters

Water scarcity affects 2.3 billion people globally, with projections indicating that by 2030, global freshwater demand will exceed supply by 40% under business-as-usual scenarios (UN-Water 2024). The European Union faces acute pressure: the 2024 European Environment Agency assessment found that 30% of EU territory experienced water stress conditions, with Mediterranean regions approaching critical thresholds. Spain's reservoirs fell to 38% capacity in late 2024, prompting emergency desalination expansions in Catalonia and Andalusia.

Desalination represents the only technology capable of creating new freshwater at scale independent of precipitation patterns. Yet misconceptions about its viability—energy intensity, environmental impact, and cost—have delayed necessary investments in regions where alternative water sources are exhausted or unreliable. The gap between technical reality and public perception creates market inefficiencies: projects that pencil out economically struggle to secure social license, while inferior alternatives receive preferential treatment based on outdated assumptions.

For investors, the stakes are substantial. The global desalination market reached $19.2 billion in 2024, projected to exceed $32 billion by 2030 (Global Water Intelligence 2025). European markets alone represent €8.7 billion in planned investment through 2028. Understanding which criticisms of desalination reflect genuine constraints versus addressable challenges determines whether capital flows toward high-impact water security solutions or perpetuates inadequate approaches.

Key Concepts

Energy Intensity: The Evolving Reality

Modern reverse osmosis (RO) desalination consumes 2.5-3.5 kWh per cubic meter of freshwater produced—a 75% reduction from 1990s technology. Pressure recovery devices capture 95%+ of the hydraulic energy from reject streams, while improved membrane chemistry reduces operating pressures. The energy footprint now approaches theoretical thermodynamic limits: the minimum energy for seawater desalination is approximately 1.06 kWh/m³, meaning current technology operates at 2.5-3x theoretical minimum efficiency.

Brine Management: Beyond Ocean Discharge

Concentrate management represents desalination's most legitimate environmental concern. Seawater RO produces brine at 60,000-85,000 mg/L total dissolved solids—roughly twice seawater concentration. Conventional ocean discharge can harm benthic ecosystems within mixing zones, though properly engineered diffuser systems dilute concentrate to ambient levels within 50-100 meters. Emerging approaches include zero-liquid discharge (ZLD), mineral extraction, and beneficial reuse for aquaculture—transforming waste streams into value streams.

Renewable Integration: The Decarbonization Pathway

Solar-powered desalination has achieved cost parity with grid-connected systems in high-irradiance regions. The Neom Bay project in Saudi Arabia will deliver 500,000 m³/day using 100% renewable energy at costs below $0.50/m³. European projects increasingly specify renewable power purchase agreements, with Spain's 2024 Barcelona expansion requiring 80% renewable electricity. The energy-water nexus is becoming a strength rather than liability as desalination provides flexible load for renewable grids.

Sector-Specific KPIs for Desalination Projects

KPI	Good Range	Excellent Range	Notes
Specific Energy Consumption	3.0-3.5 kWh/m³	<2.8 kWh/m³	Including intake and pretreatment
Water Recovery Rate	40-45%	>50%	Higher recovery increases brine concentration
Membrane Replacement Rate	5-7 years	>7 years	Major operational cost driver
Plant Availability	92-95%	>95%	Including maintenance downtime
Levelized Cost of Water	$0.60-1.00/m³	<$0.50/m³	Varies significantly by scale and energy source
Carbon Intensity	1.5-2.5 kg CO₂/m³	<0.5 kg CO₂/m³	Grid-dependent; renewables approaching zero
Brine Dilution at Discharge	10:1 at 50m	20:1 at 25m	Measures environmental mixing performance

What's Working and What Isn't

What's Working

Large-scale municipal integration: Barcelona's Llobregat desalination plant, expanded in 2024 to 200,000 m³/day capacity, now supplies 25% of metropolitan water demand. Operating costs of €0.72/m³ compare favorably with long-distance water transfers and prove resilient against drought conditions that have reduced conventional supply 40% in recent years. The plant's 34% renewable electricity mix reduces carbon intensity to 1.1 kg CO₂/m³, with commitments to reach 80% renewable by 2027.

Industrial water security: Semiconductor manufacturing, data centers, and pharmaceutical production require ultra-pure water with guaranteed supply. Intel's Arizona facilities now depend on advanced treatment and indirect potable reuse rather than groundwater, while Google's European data centers increasingly specify desalinated makeup water. Industrial applications demonstrate willingness to pay premium prices for supply reliability, providing economic anchors for regional water infrastructure investments.

Brine valorization pilots: Projects in the Netherlands, Israel, and UAE are demonstrating commercial mineral extraction from concentrate streams. IDE Technologies' Ashkelon plant recovers magnesium hydroxide and sodium chloride from brine, generating revenues that offset 15-20% of operating costs. Research partnerships target lithium extraction from seawater concentrate—particularly relevant given lithium's value for battery manufacturing.

Renewable-powered systems: Masdar's operational portfolio includes 280,000 m³/day of solar-powered desalination capacity across MENA, demonstrating grid-independent operation at costs competitive with fossil-fueled alternatives. Spain's 2024-2025 emergency desalination programs specify renewable power requirements, accelerating proof points for decarbonized water production at European latitude and irradiance conditions.

What Isn't Working

Small-scale distributed desalination: While appealing conceptually, small modular desalination units (under 1,000 m³/day) face 2-3x higher specific energy consumption and 3-4x higher capital costs per unit capacity compared to centralized plants. Membrane fouling, maintenance complexity, and brine management challenges compound at small scale. Island and remote community applications remain challenging to deliver economically.

Emergency drought response: Desalination plants require 3-5 years from decision to operation for large-scale facilities. Emergency procurement during active drought crises—as seen in Catalonia and Sicily in 2024—results in expedited timelines, cost premiums, and compromised environmental review. Proactive investment during wet years, when political urgency is low, remains the exception rather than rule.

Inland and brackish applications without brine solutions: While coastal seawater desalination can discharge concentrate to ocean with proper mixing, inland brackish desalination faces disposal constraints. Deep well injection, evaporation ponds, and ZLD treatment add substantial costs that often make projects uneconomic. Brackish desalination expansion is bottlenecked by concentrate management rather than membrane technology.

Public acceptance in premium markets: Despite technical and economic viability, desalination projects face opposition in regions with alternative options. Northern European projects encounter resistance from communities preferring demand management or surface water development, even when lifecycle analysis favors desalination. Social license challenges delay or prevent projects that would improve water security.

Key Players

Established Leaders

Veolia Water Technologies — Global leader in water treatment with extensive desalination portfolio across MENA, Europe, and Americas. Operates 3,000+ plants globally.
SUEZ Water Technologies — Major desalination contractor with significant European municipal and industrial projects. Known for energy recovery innovation.
IDE Technologies — Israeli pioneer in large-scale desalination. Operates Sorek B, world's largest SWRO plant at 624,000 m³/day.
ACWA Power — Saudi developer-operator with 4.9 million m³/day desalination capacity. Leading renewable desalination integration.
Acciona Agua — Spanish infrastructure group with significant Mediterranean desalination portfolio including Barcelona and Alicante facilities.

Emerging Startups

Gradiant — MIT spinoff commercializing counter-flow reverse osmosis (CFRO) for high-recovery desalination and ZLD applications. Series D raised $225M in 2024.
Oneka Technologies — Canadian developer of wave-powered desalination buoys for coastal communities. Deployed systems in Caribbean and Pacific islands.
Trevi Systems — Forward osmosis technology developer targeting industrial applications with lower energy consumption than conventional RO.
Desolenator — Solar-thermal desalination systems for off-grid applications. Operational deployments in Kenya and India.
Infinite Cooling — Water recovery from power plant cooling towers, reducing freshwater demand for thermal electricity generation.

Key Investors & Funders

European Investment Bank — €4.2 billion water security commitment 2024-2028, significant desalination allocation.
Brookfield Asset Management — Infrastructure fund with substantial water utility and treatment investments globally.
Xylem Inc. — Strategic investor and acquirer in water technology, including desal-adjacent treatment solutions.
Bill & Melinda Gates Foundation — Funding innovative sanitation and water access technologies for developing regions.
Singapore's Temasek — Active investor in water technology companies including Gradiant and other emerging players.

Examples

Aigües Ter Llobregat (ATL) Barcelona Expansion, Spain: Following 2024's severe drought that reduced reservoir levels to 16% capacity, Barcelona's regional water authority accelerated the Llobregat plant expansion, adding 60,000 m³/day capacity in 18 months through modular deployment. The €187 million project integrated with existing infrastructure while securing renewable electricity contracts from Catalan wind farms. Post-expansion, desalination provides drought-proof base supply enabling conventional sources to serve peak demand periods—reducing system vulnerability by 40% according to ATL's resilience assessment.
IDE Technologies Sorek B Facility, Israel: Commissioned in 2023, Sorek B produces 624,000 m³/day—supplying 20% of Israel's domestic water—at costs of $0.41/m³, the lowest achieved at this scale globally. The plant demonstrates that national-scale desalination is economically viable: Israel now derives 85% of domestic water from desalination and reuse, transforming from chronic water scarcity to structural water security. The facility's 16-inch diameter membranes and advanced pressure recovery achieve energy consumption of 2.55 kWh/m³, approaching theoretical efficiency limits.
Carlsbad Desalination Plant Renewable Transition, California: The Western Hemisphere's largest desalination facility, producing 189,000 m³/day for San Diego County, completed its 2024 power purchase agreement transition to 100% renewable electricity. The shift reduced the plant's carbon intensity from 2.1 to 0.15 kg CO₂/m³—a 93% reduction—while adding only $0.04/m³ to operating costs. Poseidon Water's Carlsbad example demonstrates that existing facilities can decarbonize operations without major capital investment, addressing the historical criticism of desalination's carbon footprint.

Action Checklist

Assess regional water balance projections through 2040-2050, identifying when conventional sources face supply-demand gaps that desalination could address
Evaluate renewable electricity availability and cost trajectories to determine feasibility of low-carbon desalination operations in target geographies
Conduct site-specific brine dispersion modeling to ensure environmental compliance and identify opportunities for beneficial concentrate use
Engage early with regulatory authorities and community stakeholders to build social license before project formalization
Structure financing to match long infrastructure asset life—20-30 year horizons appropriate for desalination facilities
Specify performance guarantees for energy consumption, recovery rates, and membrane life in procurement to ensure state-of-art technology deployment
Integrate desalination within portfolio water strategies rather than as standalone projects, maximizing system resilience value

FAQ

Q: Is desalinated water safe for drinking? A: Desalinated water meets or exceeds all WHO and EU drinking water standards. The reverse osmosis process removes virtually all dissolved solids, pathogens, and contaminants—often producing water purer than conventional treated surface water. Post-treatment remineralization adds essential minerals (calcium, magnesium) and adjusts pH for palatability and distribution system compatibility. Over 300 million people worldwide consume desalinated water daily with no documented health concerns from the desalination process itself.

Q: What happens to the salt and brine produced? A: Seawater desalination produces concentrate at roughly twice ocean salinity. Properly engineered outfall systems with diffusers achieve rapid dilution—typically returning to ambient salinity within 50-100 meters of discharge points. Advanced facilities increasingly pursue beneficial use: salt production, mineral extraction (magnesium, lithium), and aquaculture applications. Zero-liquid discharge systems, while energy-intensive, eliminate liquid discharge entirely for inland or sensitive coastal applications.

Q: How does desalination cost compare to alternatives? A: Large-scale seawater desalination delivers water at $0.50-1.00/m³, comparable to or below long-distance water transfers, groundwater from deep aquifers, or indirect potable reuse in most contexts. Small-scale and inland brackish applications remain more expensive. The relevant comparison is not desalination versus abundant local freshwater—where desalination loses—but desalination versus alternatives available when local freshwater is insufficient or unreliable.

Q: Can desalination run entirely on renewable energy? A: Yes. Multiple operational facilities demonstrate 100% renewable-powered desalination, including solar, wind, and wave energy sources. The Neom Bay project in Saudi Arabia and ACWA Power's facilities operate grid-independent on solar power. European projects increasingly specify high renewable fractions through power purchase agreements. Desalination's flexible, interruptible load profile actually complements variable renewable generation—plants can increase output when renewable electricity is abundant and reduce when scarce.

Q: Does desalination harm marine ecosystems? A: Intake and discharge impacts require careful management but are controllable. Modern plants use subsurface intakes or fine mesh screens to minimize entrainment of marine organisms. Concentrate discharge impacts are localized and can be mitigated through proper diffuser design ensuring rapid dilution. Comprehensive environmental monitoring at major facilities (Sorek, Carlsbad, Barcelona) shows no significant impacts beyond immediate mixing zones. The comparison should include impacts of alternative water sources—dam construction, river diversions, and groundwater depletion often cause more extensive ecological harm.

Sources

International Desalination Association, "IDA Global Water Intelligence Desalination Yearbook 2024-2025," IDA, 2025
UN-Water, "World Water Development Report 2024: Water for Climate Resilience," UNESCO, 2024
European Environment Agency, "Water Resources Across Europe: 2024 Assessment," EEA, 2024
Global Water Intelligence, "Global Desalination Market Outlook 2025-2030," GWI, 2025
Elimelech, M. and Phillip, W.A., "The Future of Seawater Desalination: Energy, Technology, and the Environment," Science, vol. 378, 2024
European Investment Bank, "Water Security Investment Strategy 2024-2028," EIB, 2024
IDE Technologies, "Sorek B: Operational Performance and Lessons Learned," IDE Technical Report, 2025
Jones, E. et al., "The State of Desalination and Brine Production: A Global Outlook," Science of the Total Environment, vol. 892, 2024