Desalination has transformed from a supplementary technology to a crucial element of global water security. In response to population growth, climate crises, and rising water stress, many countries are increasingly adopting desalination to secure drinking water and support industrial needs.
Over the past decades, the sector has developed significantly, emerging as a reliable and expanding alternative. The Spanish Association of Desalination and Water Reuse (AEDyR) presents ten key facts to dispel misconceptions about desalination, emphasizing its affordability, energy efficiency, and minimal environmental impact. This summary highlights these key points.
1.Cost of Desalinated Water
Contrary to popular belief, desalinated water is not expensive. Currently, the cost of producing desalinated seawater ranges from 0.5 to 1.0 euro per cubic meter, while desalinating brackish water costs between 0.3 and 0.5 euros. These costs encompass infrastructure amortization, operation, maintenance, and energy, which represents the largest portion of expenses. When broken down, a liter of desalinated water costs between 0.0003 and 0.0010 euros. This affordability makes desalinated water a viable resource for drinking, agricultural irrigation, and various industrial applications.
2.Energy Efficiency in Desalination Processes
Another myth is that desalination consumes excessive energy. In reality, the energy consumption of a desalination plant is about 3 kWh per cubic meter of water produced, translating to approximately 0.003 kW for each liter of fresh water. For a family of four, the annual energy needed for desalinating their water consumption is equivalent to the energy used by a refrigerator in the same period. This means that daily electricity usage for desalination would be comparable to that of an air conditioner running for 1-2 hours.
3.Environmental Impact of Desalination
Desalination’s impact on the marine environment is often overstated. Scientific studies indicate that the discharge of brine from desalination plants does not significantly affect marine ecosystems. The dilution and diffusion systems in place ensure that the concentrate blends with seawater, maintaining similar salinity and quality just meters from the discharge point. All major desalination facilities in Spain undergo strict environmental assessments and monitoring, confirming their minimal impact on marine life. Interestingly, some studies suggest that the oxygenation from these discharges may even enhance local marine biodiversity.
4.Spain’s Leadership in Desalination
Spain has been constructing desalination plants for 60 years, gaining significant expertise in their management. This experience, coupled with successful international partnerships, has positioned Spanish companies as leaders in the global desalination market, winning contracts across five continents, including Australia, Chile, and the United States.
Many of Spain’s large desalination plants utilize cutting-edge technologies and attract international delegations eager to learn from their advanced facilities and operational practices. This leadership underscores Spain’s pivotal role in the development and innovation of desalination technology worldwide.
5.Using desalinated water for agriculture
Desalinated water is not only used for drinking but also plays a crucial role in agriculture and industry. Farmers often mix it with other water sources to lower costs, but for high-value greenhouse crops, water expenses represent only 5% of production costs, with productivity between 5 and 7 € per cubic meter. This makes pure desalinated water viable for irrigation, providing reliable access regardless of weather conditions. In industry, desalinated water serves various roles, including as service water, in steam production, and as a raw material for beverages, juices, and other products.
6.Quality and Taste of Desalinated Water
Desalinated water is of excellent quality and tastes good, meeting the Spanish Royal Decree on Drinking Water and the European Directive 2020/2184. Utilizing advanced reverse osmosis technology, it effectively eliminates both chemical and biological contaminants, ensuring superior safety compared to conventional treatment methods.
Over 21% of Spain’s desalinated water is used in agriculture, highlighting its technical and economic viability. The water’s purity allows for tailored remineralization, adding necessary nutrients as per health authority guidelines, and its carbonate content enables the creation of water with various flavor profiles.
7.Composition of Concentrate from Desalination
The concentrate produced by desalination plants is essentially seawater that has not undergone treatment, containing a higher concentration of salts but no toxic components. For every 100 liters of seawater processed, about 40-45 liters of fresh water is produced, leaving 55-60 liters of concentrated seawater with an increased salt concentration—approximately 70 grams of salt per liter, equivalent to two tablespoons. This concentrate contains only substances present in seawater and adheres to strict regulations preventing toxic additions. Current studies explore its potential as an economic resource, suggesting uses in electricity generation and aquaculture, alongside projects focused on recovering valuable compounds for industrial applications within a circular economy framework.
8.Desalination as a Negative Emissions Technology
Desalination plants do not release CO2 directly into the atmosphere. While they consume electricity from the national grid, any CO2 emissions linked to desalination are indirect, arising from the energy production systems of the grid, which include both fossil and renewable sources, similar to other industries. Consequently, as the share of renewable energy in the national electricity grid rises, the indirect CO2 emissions associated with desalination will decrease.
9.Desalination as a Solution to Drought and Climate Change
Desalination is one of the solutions to combat drought and climate change, complementing measures such as water saving, reducing losses in networks, and reusing regenerated wastewater. It has the advantage of being fed by an inexhaustible source—seas and oceans—making it independent of weather conditions and suitable for areas with water deficits. Desalination plants produce no direct emissions to the atmosphere and can ensure water supply to populations, even if they operate below 100% capacity during periods when natural water sources are available. Thus, it serves as a reliable water source amid increasing water stress.
10.Sustainability of Desalination
Desalination is a sustainable method of converting seawater into fresh water without depleting inland resources. Recognized by the European Union under the Green Taxonomy, it mitigates climate change effects and supports Sustainable Development Goals. The integration of renewable energy sources, such as solar, wind, and green hydrogen, is growing in modern desalination plants. The sector focuses on sustainability by optimizing concentrate return processes, reducing energy consumption, and exploring concentrate revalorization. Additionally, hybrid systems that combine desalination with thermal energy storage or battery technology enhance efficiency, making desalination plants more independent from fossil fuel energy grids as energy storage technology advances. Overall, desalination contributes to climate change adaptation while ensuring a reliable water supply.
In summary, the AEDyR emphasizes that water desalination is a cost-effective, energy-efficient, and environmentally responsible method to provide high-quality water, making it a crucial resource in addressing global water scarcity and climate challenges.
References
1- 10 CERTAINTIES About WATER DESALINATION
https://aedyr.com/wp-content/uploads/2024/04/10-Certezas-Desalacion-Agua-AEDyR.pdf
