Omnipresent wind and solar energies have the same problem: intermittency. The wind does not always blow and the sun does not always shine. This dependence on weather conditions It forces us to look for storage solutions OA depend on a 24/7 available source to have a constant supply. But what if that other source was also renewable energy?
Japan bets on osmotics. In August, the Japanese city of Fukuoka launched the First osmotic energy center in the country. It is just the second installation of this type in the world and represents more than a pilot test for a technology that promises to revolutionize the energy mix. “I hope it extends not only in Japan, but throughout the world,” said Akihiko Tanioka, an expert in the field of the Tokyo Science Institute.
The plant will generate about 880,000 kilowatts-Hora a year to feed part of the desalination plant that supplies fresh water to the city. Although it may seem like a modest figure, equivalent to the consumption of about 220 Japanese homes, its true value is that it works continuously. It is not affected by the weather or time of day, and does not emit carbon dioxide.
The power to mix fresh and salted water. Osmotics is a new generation renewable energy based on A natural phenomenon that we all study at the institute: osmosis. When two solutions with different salt concentration are separated by a semipermeable membrane (which lets the water pass, but not the salt), the water of the less concentrated solution flows naturally towards the most concentrated to try to balance the mixture.
Fukuoka’s plant places fresh water (treated wastewater) on one side of the membrane, and salt water (sea water) to the other. Fresh water crosses the membrane to the salt water side, increasing volume and pressure on that side. The conression is used to move a turbine that, connected to a generator, produces electricity. Therefore, this renewable source is also known as saline gradient energy or “blue energy”.
From the initial promises to the first problems. This technology is not exactly new. Already in 2017, in Xataka we echoed its enormous potential: The studies suggested that it could generate up to 40% of the world energy demand if it would be used in the mouths of all rivers. The challenge was the efficiency of the membranes and the cost of the facilities.
The first systems, such as delayed pressure osmosis, suffered bioincructing problems: bacteria blocked membranes, drastically reducing their effectiveness. Other systems, such as “inverse electrodialysis”, were more durable but generated very little energy. The Fukuoka plant, like the first in the world inaugurated in Denmark in 2023 by the Saltpower company, demonstrates that progress in membrane technology is allowing to overcome these obstacles.
Nanotechnological membranes. In France, the company Sweetch Energy has developed Much more efficient nanometric size membranes, capable of generating between 20 and 30 watts per square meter. In comparison, the most advanced systems to date generate 12.6 watts.
The company seeks to install its first real -scale generator, Osmorhône 1, at the mouth of the Rhone River. The potential of this unique river would reach 500 MW, equivalent to mid -nuclear reactor capable of supplying two million people. And it would be just the beginning. All deltas and estuaries in the world release 30,000 energy from each year, a figure similar to world demand of electricity.
Salina bachata in Fukuoka. In addition to the friction of the membranes, the osmotics also loses energy in water pumping. But, as he explains The Guardianthe new Fukuoka plant uses the concentrated brine that remains of the desalination process to increase the salinity difference and, thus, the energy potential available.
The inauguration of the Japanese plant and the advances of companies such as Sweetch Energy mark a turning point for the osmotics. They are the first steps to stop being a laboratory promise and become an industrial reality. In a clean, permanent energy, which does not depend on the climate and that can be integrated into existing infrastructures such as ports, desalination makers or locks. Japan has made its bet: the mixture of fresh and salted water will be part of its energy mix.
Image | Umi-No-Nakamich Desalination Plant (Obayashi)
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