Why is water desalination so expensive?

The cost of desalination is relatively high, mainly due to the following reasons:

Technical complexity and equipment costs

Desalination processes require complex technology and high-end equipment, which are often costly. Reverse osmosis technology, for example, requires high-quality reverse osmosis membranes that are relatively expensive to produce and maintain.

Energy consumption

Desalination is an energy-intensive process, especially with traditional technologies such as thermal and distillation. They need to consume a lot of electricity or heat to drive the desalination process, which makes the energy cost of desalination a large proportion of the total cost. In today’s high electricity prices, energy costs have become an important factor affecting the cost of desalination.

Water treatment and environmental protection

The desalination process produces large amounts of highly concentrated brine (also known as “concentrated brine”), which can pollute the marine ecosystem if not treated properly. As a result, desalination plants need to invest additional costs to ensure that this brine is properly disposed of to reduce the negative impact on the environment.

Operation and maintenance costs

Desalination plants require professional operation and maintenance teams to ensure the uptime and performance of the equipment. These teams need to receive professional training and need to regularly maintain and replace equipment components to ensure the continued stable operation of the desalination plant. These operating and maintenance costs also add to the total cost of desalination.

Market demand and scale effect

If the demand for desalination in a certain region is relatively small, then the scale of a single desalination plant will also be relatively small, and it is difficult to form a scale effect. This can lead to higher unit costs for individual desalination plants. Conversely, if there is a large demand for desalination in a certain area, then a larger-scale desalination plant can be built to form a scale effect, thereby reducing unit costs.


In summary, the relatively high cost of seawater desalination is mainly due to the combination of technical complexity and equipment costs, energy consumption, water treatment and environmental protection, operation and maintenance costs, market demand and scale effects. In order to reduce the cost of seawater desalination, it is necessary to continuously develop new technologies, optimize equipment design, improve energy efficiency, strengthen environmental protection measures, and expand market demand.