🚰 Energy consumption for desalinating water has decreased by 85 percent

Technical advances in desalination

Desalination of seawater has made significant progress over the past decades. In the 1970s, about 20 kilowatt-hours (kWh) of energy was required to desalinate one cubic meter of water. Today, that figure has dropped to between 2.5 and 3.5 kWh, writes Hannah Ritchie on Sustainability by the Numbers.

Providing all eight billion people on Earth with desalinated drinking water would require 31 TWh of electricity per year. This can be compared to the world’s current annual electricity production of about 30,000 TWh. Such a global investment in desalinated drinking water would thus only increase global electricity consumption by 0.1 percent.

The dominant technology for desalination is reverse osmosis, where water is pressed through a semipermeable membrane that filters out salt and impurities. This method is significantly more energy-efficient than thermal desalination.

Energy consumption for households

If an average American household were to get all its water from desalination, it would increase their electricity consumption by about 13 percent. For a British household, the increase would be around 15 percent.

In the US, the energy demand for desalination would be at about the same level as for dehumidifiers and significantly lower than for water heating or air conditioning.

Costs of desalination

The costs of desalinated water vary, but are usually between $1 and $2.50 per cubic meter. Some facilities, such as Sorek B in Israel, produce water at prices as low as $0.41 per cubic meter.

For a person in the US, it would cost about $170 per year to get all their household water from desalination. In Britain, the cost would be about $159 per year.

Producing enough drinking water for one person – about 3 liters per day – through desalination would cost only $2.30 for an entire year. This is less than the cost of a single bottle of water in many countries.

If desalination were used to provide drinking water to the entire world’s population, it would increase global electricity consumption by only 0.1%.

Limitations for agriculture

Despite advances in desalination, the technology is still not economically viable for large-scale agriculture. Using desalinated water for wheat production in Britain, for example, would cost three times more than the current market price for wheat.

For many countries, a transition to desalinated water for agriculture would require doubling the country’s total electricity production, making it an unsustainable solution for large-scale national droughts.

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SDGs, Targets, and Indicators

SDGs	Targets	Indicators
SDG 6: Clean Water and Sanitation	6.4: By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity	– Energy consumption for desalination has decreased from 20 kWh per cubic meter in the 1970s to 2.5-3.5 kWh today. – Producing enough drinking water for one person – about 3 liters per day – through desalination would cost only $2.30 for an entire year.
SDG 7: Affordable and Clean Energy	7.2: By 2030, increase substantially the share of renewable energy in the global energy mix	– Energy consumption for desalination has decreased from 20 kWh per cubic meter in the 1970s to 2.5-3.5 kWh today. – Providing all eight billion people on Earth with desalinated drinking water would require 31 TWh of electricity per year. This can be compared to the world’s current annual electricity production of about 30,000 TWh.
SDG 9: Industry, Innovation and Infrastructure	9.4: By 2030, upgrade infrastructure and retrofit industries to make them sustainable, with increased resource-use efficiency and greater adoption of clean and environmentally sound technologies and industrial processes, with all countries taking action in accordance with their respective capabilities	– Energy consumption for desalination has decreased from 20 kWh per cubic meter in the 1970s to 2.5-3.5 kWh today. – The dominant technology for desalination is reverse osmosis, which is significantly more energy-efficient than thermal desalination.
SDG 12: Responsible Consumption and Production	12.2: By 2030, achieve the sustainable management and efficient use of natural resources	– Energy consumption for desalination has decreased from 20 kWh per cubic meter in the 1970s to 2.5-3.5 kWh today. – The costs of desalinated water vary, but are usually between $1 and $2.50 per cubic meter.
SDG 13: Climate Action	13.3: Improve education, awareness-raising, and human and institutional capacity on climate change mitigation, adaptation, impact reduction, and early warning	– Energy consumption for desalination has decreased from 20 kWh per cubic meter in the 1970s to 2.5-3.5 kWh today. – Providing all eight billion people on Earth with desalinated drinking water would require 31 TWh of electricity per year. This can be compared to the world’s current annual electricity production of about 30,000 TWh.