Faced with the growing challenges of water scarcity, many parts of the world are turning to seawater desalination. However, behind current desalination techniques lie worrying ecological consequences, highlighting the incompatibility of these techniques with contemporary issues.
Desalination at all costs, but at what energy cost?
Seawater desalination, using a variety of methods, is presented as a response to the increasing scarcity of water resources. However, the desalination process takes a heavy toll in terms of energy. Thermal methods, based on the distillation of salt water, and reverse osmosis, currently the most widespread, require a significant amount of energy. In some areas, between 30% and 50% of treated water never reaches consumers due to leaks in poorly maintained pipes.
Fossil fuels, a vicious circle
Desalination represents a considerable energy demand, accounting for up to 6% of electricity consumption in Saudi Arabia. Worse still, most desalination plants run predominantly on fossil fuels, notably in the United Arab Emirates, Saudi Arabia, Kuwait and Oman, which are among the world’s largest producers of desalinated water. These desalination plants make an alarming contribution to global carbon dioxide emissions, estimated at 120 million tonnes every year, equivalent to Belgium’s total annual emissions. Desalination could release a further 280 million by 2050, equivalent to France’s emissions in 2021, according to the World Bank. In 2017, renewable energies accounted for just 1% of the energy demand required by the world’s 20,000 desalination plants, according to a study on ScienceDirect.
Alarming ecological consequences
In addition to the energy issue, the desalination process has a negative impact on the environment. Every liter of desalinated water produces 1.5 liters of polluted liquid, usually discharged into the sea, endangering marine flora and fauna. Every day, the desalination plants discharge 141.5 million cubic meters of brine, a concentration of seawater enriched with chemicals such as anti-tartar, anti-chlorine and anti-foaming agents. This brine contributes to the increase in water salinity, creating a vicious circle that amplifies the phenomenon of ocean deoxygenation. The vicious circle closes: less oxygenated water captures less CO2, contributing to the amplification of climate change.The vicious circle closes: less oxygenated water captures less CO2, contributing to the amplification of climate change. The consequences for marine biodiversity, particularly fragile ecosystems, are alarming. Experts point out that this practice represents a major ecological risk, threatening the survival of various marine organisms, including corals and molluscs. Scientists warn of the rapid deterioration of these crucial ecosystems.
Cryoseparation: an agile, economical and environmentally-friendly technology
The idea of desalinating seawater may seem attractive as a way of alleviating water shortages, but high energy costs, massive greenhouse gas emissions and serious ecological repercussions make it a solution incompatible with contemporary challenges. That’s why Seawards is developing a technology that consumes less energy, pollutes less and costs less. Cryo-separation enables us to rethink our approach to water management, focusing on sustainable, environmentally-friendly solutions rather than embarking on a path that could exacerbate the problems we’re trying to solve.