Seawater desalination by nuclear energy

Fresh water is a precious commodity and a limited resource, so the growth of the global population means that new sources of water must be found. In this respect, seawater desalination methods are becoming increasingly important. However, they require energy to carry them out and, in this respect, nuclear energy can effectively meet these needs.

If the amount of available water were distributed equally among all the planet's inhabitants, each person would have 16,000 litres of water per day or 5,800 cubic metres per year. Unfortunately, this is not the reality and, for example, in Iceland, rainfall yields 1.4 million litres per person per day, while in Kuwait the amount of rainwater yields an average of only 16 litres per person per day.

The United Nations (UN) classifies degrees of water insufficiency into three categories:

  • Water stress: When the amount of water available in a country is less than 4,600 liters per day per capita (1,700 cubic meters per year).
  • Water scarcity: When this quantity is less than 2,700 liters per day per capita.
  • Absolute water scarcity: When rainfall is below the threshold of 1,400 liters per capita daily.

In its 2022 Sustainable Development Goals Report, the UN states that over the last century, global water consumption has more than doubled about the rate of population growth. This growth, combined with socio-economic development, changing consumption patterns and climate change, increases the water demand. Conventional water sources such as precipitation and snowmelt are no longer sufficient to meet the needs of people living in water-scarce regions.

Water use and wastewater treatment require electricity for their supply, distribution and transport. According to a study by the International Energy Agency (IEA), these operations accounted for approximately 4 % of global electricity consumption in 2014. The IEA estimates that electricity consumption in the water sector will double by 2040.

Water desalination technologies

There are approximately 16,000 desalination plants in operation worldwide, which together produce some 95 million m3 of desalinated water per day.

Before the 1980s, 84% of the world's desalinated water was produced by multi-stage flash (multi-stage flash distillation, or MSF) and multi-effect (multi-effect, or ME) technology, and later membrane technology, such as reverse osmosis, was developed. In 2000, 11.5 million m3 of water was desalinated per day, the same volume as with thermal technologies, and all these technologies together provided 93% of desalinated water production. Since then, the number and capacity of desalination plants have increased exponentially, while thermal plants have grown very slowly.

According to the UN, water supply and wastewater treatment produce between 3 and 7 % of global greenhouse gas emissions. Much of these emissions are due to the generation of energy needed to operate the systems, or to the biochemical processes involved in water and wastewater treatment.

This amount of energy will increase. The IEA forecasts that electricity consumption for desalination will increase to about 345 TWh in 2040, up from 40 TWh in 2014.

The first desalination facility attached to a nuclear power plant was built by the Soviet Union in 1973 at the Aktau site (today on Kazakh territory) until its decommissioning. According to the International Atomic Energy Agency (IAEA), Kazakhstan has a nuclear desalination relaunch project in collaboration with Russia. Subsequently, several countries such as India, Japan and Pakistan started using nuclear units to desalinate seawater, in addition to producing electricity. Other countries such as Saudi Arabia, Argentina, China, South Korea, Egypt and Russia have projects to build nuclear desalination plants.

Desalination plant at the Karachi nuclear power plant in Pakistan

According to the IAEA, nuclear desalination is a viable option to meet the growing demand for drinking water. The IAEA makes available to its interested Member States calculation programmes to help them assess the value of nuclear desalination. With these programmes, they can perform economic and thermodynamic analyses of the coupling of different energy resources with various desalination processes.

Freshwater for agriculture using isotope techniques

Agriculture accounts for about 70 % of global freshwater consumption, but less than half of this water is used efficiently. The rest is lost through evaporation, infiltration and runoff. This water, whether from rainfall or irrigation, transports nutrients, pesticides and chemicals to surface and groundwater, affecting water quality and the environment.

Isotope and nuclear techniques are helping to improve soil and irrigation management by instituting more efficient water use practices. These techniques are gradually being incorporated into agricultural water management, as isotopes such as oxygen-18 and deuterium can help determine the source and movement of water in plants and soils. For example, scientists can use isotopes to measure how much water a plant consumes, how much it "transpires" and how much evaporates from the soil. This information helps develop strategies to improve crop production, reduce water loss and prevent damage to soils, water and ecosystems.

In short, nuclear technology offers an environmentally friendly and sustainable solution to increase, optimise and improve water resources across the globe, both for drinking and agriculture.

Tipos:
Access to the best

educational
resources

on Energy and Environment
Go to resources