A new way to generate electricity from waterAn age-old technique updated with futuristic materialsWater has long been a source of renewable powe...
Published by Water Network Research, Official research team of The Water Network
A new way to generate electricity from water
An age-old technique updated with futuristic materials
Water has long been a source of renewable power. More than 2,000 years ago the Chinese used water wheels to grind grain and pound ore. In the 1700s water wheels kickstarted the Industrial Revolution in Britain. In the 1870s a Victorian industrialist, William Armstrong, installed the world’s first hydroelectric system to light his family home, Cragside, in north-east Britain.
The latest idea is based on osmosis, a natural process in which water will move from a place with lower concentration of, for example, salts, through a semipermeable membrane and into a more concentrated solution. This continues until both sides reach equilibrium.
Power can be made from this process because the volume of salty water increases as it is diluted with fresh water that passes through the membrane. Some of the resulting outflow of water from the saltier side is then tapped to drive a turbine to produce the electricity.
Osmotic power might one day provide useful base-load energy to coastal communities with an abundance of salty water, in areas like Australia and the Middle East. It could also help recover energy from desalination plants. Recent projects under way in Japan and France show how the technology is developing.
In August a ¥700m ($4.5m) osmotic power plant opened in Fukuoka, a city on the northern shore of Japan’s Kyushu Island. With a generating capacity of 110 kilowatts, enough for 200 typical homes, the energy will be used to run an adjacent desalination plant that produces fresh water for the city.
Desalination plants are hungry users of electricity and most, like the one in Fukuoka, employ a process called reverse osmosis. This goes against the natural osmotic flow by pumping seawater at high pressure through a semipermeable membrane to remove the salt. It leaves behind a waste stream of extremely salty water that, when pumped back into the sea, can harm the local environment.
The Fukuoka osmotic power plant uses the waste brine from the nearby desalination plant which, being highly concentrated, makes the osmosis work faster. And instead of using valuable fresh water from desalination, the plant is supplied with treated water from a sewage works. The Fukuoka District Waterworks, which runs the project, hopes eventually the osmotic power plant will be efficient enough to produce more electricity by adding saltwater drawn directly from the sea to the brine coming from the desalination plant.
One of the main reasons why osmotic power has become more viable today is thanks to the development of precisely tailored membranes. These have improved water permeability and are less liable to clogging by impurities. Such membranes make desalination plants more efficient.
Sweetch Energy is a company building an osmotic power plant on the river delta where the Rhone meets the Mediterranean Sea in southern France. With a warm, sunny climate causing a high rate of evaporation, the waters of the Mediterranean are particularly salty. If a trial plant currently being constructed operates as planned and proves the technology works, the company aims to construct a bigger installation over the next decade.
SOURCE:https://www.economist.com/science-and-technology/2025/11/26/a-new-way-to-generate-electricity-from-water
An age-old technique updated with futuristic materials
Water has long been a source of renewable power. More than 2,000 years ago the Chinese used water wheels to grind grain and pound ore. In the 1700s water wheels kickstarted the Industrial Revolution in Britain. In the 1870s a Victorian industrialist, William Armstrong, installed the world’s first hydroelectric system to light his family home, Cragside, in north-east Britain.
The latest idea is based on osmosis, a natural process in which water will move from a place with lower concentration of, for example, salts, through a semipermeable membrane and into a more concentrated solution. This continues until both sides reach equilibrium.
Power can be made from this process because the volume of salty water increases as it is diluted with fresh water that passes through the membrane. Some of the resulting outflow of water from the saltier side is then tapped to drive a turbine to produce the electricity.
Osmotic power might one day provide useful base-load energy to coastal communities with an abundance of salty water, in areas like Australia and the Middle East. It could also help recover energy from desalination plants. Recent projects under way in Japan and France show how the technology is developing.
In August a ¥700m ($4.5m) osmotic power plant opened in Fukuoka, a city on the northern shore of Japan’s Kyushu Island. With a generating capacity of 110 kilowatts, enough for 200 typical homes, the energy will be used to run an adjacent desalination plant that produces fresh water for the city.
Desalination plants are hungry users of electricity and most, like the one in Fukuoka, employ a process called reverse osmosis. This goes against the natural osmotic flow by pumping seawater at high pressure through a semipermeable membrane to remove the salt. It leaves behind a waste stream of extremely salty water that, when pumped back into the sea, can harm the local environment.
The Fukuoka osmotic power plant uses the waste brine from the nearby desalination plant which, being highly concentrated, makes the osmosis work faster. And instead of using valuable fresh water from desalination, the plant is supplied with treated water from a sewage works. The Fukuoka District Waterworks, which runs the project, hopes eventually the osmotic power plant will be efficient enough to produce more electricity by adding saltwater drawn directly from the sea to the brine coming from the desalination plant.
One of the main reasons why osmotic power has become more viable today is thanks to the development of precisely tailored membranes. These have improved water permeability and are less liable to clogging by impurities. Such membranes make desalination plants more efficient.
Sweetch Energy is a company building an osmotic power plant on the river delta where the Rhone meets the Mediterranean Sea in southern France. With a warm, sunny climate causing a high rate of evaporation, the waters of the Mediterranean are particularly salty. If a trial plant currently being constructed operates as planned and proves the technology works, the company aims to construct a bigger installation over the next decade.
SOURCE:https://www.economist.com/science-and-technology/2025/11/26/a-new-way-to-generate-electricity-from-water
Tags
- Desalination
- Desalination plant operations coordinator
- water packaged plants
- Water from Air
- Water from Urine
- Domestic Water Use
- France