Osmosis energy. Osmotic power plant: alternative energy from seawater Power plant in norway from salt water

So far, there is only one working prototype of an osmotic power plant in the world. But in the future there will be hundreds of them.

The principle of operation of an osmotic power plant

The operation of the power plant is based on the osmotic effect - the property of specially designed membranes to allow only certain particles to pass through them. For example, we will install a membrane between two containers and pour distilled water into one of them, and a saline solution into the other. Water molecules will freely pass through the membrane, but salt particles will not. And since in such a situation the liquids will strive for equilibrium, then soon fresh water will spread by gravity to both containers.

If the difference in the composition of the solutions is made very large, then the flow of liquid through the membrane will be quite strong. By placing a water turbine in its path, you can generate electricity. This is the simplest design of an osmotic power plant. At the moment, the optimal raw materials for it are salt sea water and fresh river water - renewable energy sources.

An experimental power plant of this type was built in 2009 near the Norwegian city of Oslo. Its performance is low - 4 kW or 1 W per 1 sq. M. membranes. In the near future this figure will be increased to 5 W from 1 sq. M. By 2015, the Norwegians intend to build a commercial osmotic power plant with a capacity of about 25 MW.

Prospects for the use of this energy source

The main advantage of the ECO over other types of power plants is its use of extremely cheap raw materials. In fact, it is free, because 92-93% of the planet's surface is covered with salt water, and fresh water is easy to obtain by the same method of osmotic pressure in another installation. By installing a power plant at the mouth of a river flowing into the sea, all problems with the supply of raw materials can be solved in one fell swoop. The climatic conditions for the operation of the ECO are not important - as long as the water flows, the installation works.

At the same time, no toxic substances are created - the same salt water is formed at the exit. ECO is absolutely environmentally friendly, it can be installed in close proximity to residential areas. The power plant does not harm wildlife, and for its construction there is no need to block rivers with dams, as is the case with hydroelectric power plants. And the low efficiency of the power plant is easily compensated by the massiveness of such installations.

There is no mistake in the title, not from "space", but from "osmosis"

Every day we make sure that we are surrounded by a host of the most unexpected sources of renewable energy. In addition to the sun, wind, currents and tides, salt generators can be used to generate electricity - or rather, on the difference it creates between fresh and sea water. This difference is called the salinity gradient, and due to the phenomenon of osmosis, it can be used to obtain excess fluid pressure, which is converted into electrical pressure by conventional turbines.

There are several known methods of converting the energy of the salinity gradient into electricity. The most promising for today is transformation with the help of osmosis, therefore, the energy of the salinity gradient is often referred to as the energy of osmosis. But in principle, other ways of transforming the energy of the salinity gradient are also possible.

The phenomenon of osmosis is as follows. If you take a semi-permeable membrane (membrane) and place it as a septum in some vessel between fresh and salt water, then the osmotic forces will begin, as it were, to pump fresh water into salt water. Fresh water molecules will pass through the separating membrane into the second half of the vessel, filled with salt water, and the membrane will not let salt molecules into the first half with fresh water. For this property, the membrane is called semi-permeable. The energy released during this process manifests itself in the form of increased pressure that occurs in the part of the vessel with salt water. This is the osmotic pressure (sometimes called the osmotic waterfall). The maximum value of osmotic pressure is the pressure difference between the solution (i.e., salt water) and the solvent (i.e., fresh water), at which osmosis stops, which occurs due to the formation of equal pressures on both sides of the semipermeable membrane. The resulting increased pressure in half of the salt water vessel balances the osmotic forces that displaced fresh water molecules through a semi-permeable membrane into salt water.

The phenomenon of osmosis has been known for a long time. It was first observed by A. Podlo in 1748, but a detailed study began more than a century later. In 1877, W. Pfeffer was the first to measure osmotic pressure in the study of aqueous solutions of cane sugar. In 1887, Van't Hoff, on the basis of the data of Pfeffer's experiments, established a law that determines the osmotic pressure depending on the concentration of the solute and temperature. He showed that the osmotic pressure of a solution is numerically equal to the pressure that the molecules of the solute would exert if they were in a gaseous state at the same temperature and concentration.

To obtain osmotic energy, it is necessary to have a source with a low salt concentration near a more or less concentrated solution. In the conditions of the World Ocean, such sources are the mouths of rivers flowing into it.

The energy of the salinity gradient, calculated from the osmotic pressure, is not subject to efficiency limitations associated with the Carnot cycle; this is one of the positive features of this type of energy. The question is how best to convert it into electricity.

The world's first power plant to use the phenomenon of osmosis to generate electricity recently opened in Norway. Using only salt and fresh water in its work, the current prototype of the power plant will generate 2-4 kilowatts, but in the future this figure will increase significantly. To generate energy, the station, built by the Norwegian company Statkraft, uses the phenomenon of osmosis, that is, the movement of solutions through a membrane to the side higher concentration of salts. Since the concentration of salts in ordinary sea water is higher than in fresh water, the phenomenon of osmosis develops between the fresh and salt water separated by a membrane, and the movement of the water flow forces the turbine to work, generating energy. The power of the already launched prototype is small and is two to four kilowatt-hours. As explained by the project manager Stein Erik Skilhagen, the company did not have the goal of immediately building an industrial-scale power plant, it was more important to show that this technology, in principle, can be used in the energy sector. The idea of \u200b\u200busing the phenomenon of osmosis to generate electricity was first proposed by environmental activists back in 1992. , the website of the Statkraft company notes. According to the calculations of engineers, today it is possible to build an osmotic power plant with a capacity of 1,700 kilowatts per hour. At the same time, unlike other stations on alternative energy sources - solar or wind - the weather will not have any effect on the operation of the station. The existing prototype has enough capacity to power just a coffee maker, but by 2015 Statkraft hopes to build a power plant to supply electricity to a village of 10,000 private houses.

Among the challenges ahead is the search for more energy efficient membranes. For those used at the station in Hurum, 60 km south of Oslo, this figure is 1 W / m2. After a while Statkraft will increase the power to 2-3 watts, but to reach a cost-effective level, 5 watts must be achieved.

Realizing that the reserves of fossil energy resources are limited, and the use of nuclear technologies is associated with a significant risk and rests on the problem of radioactive waste disposal, people are increasingly trying to put themselves at their service alternative energy sources. Renewable resources have a total energy potential that is 3 thousand times higher than today's needs of mankind. True, only an insignificant part of this potential lends itself to use, but even this - even at the current level of technology development - is enough to cover the energy demand by almost 6 times. Solar energy alone would be more than enough.

And yet engineers continue to seek more and more alternative energy resources - or they return to old ideas, once recognized as hopeless and therefore rejected, and now again promising success. The pilot plant launched in Norway on Tuesday also belongs to such projects. It is based on a technology that allows energy to be produced due to the pressure that occurs when fresh and salt water merges where the river flows into the sea. We are talking about the so-called osmosis.

Fresh water + sea water \u003d energy source

Usually, where the river flows into the sea, fresh water is simply mixed with salty water, and there is no pressure that could serve as a source of energy. Professor Klaus-Viktor Peinemann from the Institute for Polymer Research at the GKSS Research Center in the town of Geesthacht in the north of Germany, calls the conditions necessary for osmotic pressure to develop: "If, before mixing, sea water and fresh water are separated by a filter - with a special membrane that allows water to pass through, but impermeable to salt, then the aspiration of solutions to thermodynamic equilibrium and equalization of concentrations can be realized only due to the fact that water will penetrate into the salt solution, and salt will not enter fresh water. "

If this happens in a closed reservoir, then an excess hydrostatic pressure, called osmotic pressure, arises from the seawater. To use it for energy production, at the place where the river flows into the sea, you need to install a large reservoir with two chambers, separated from each other by a semi-permeable membrane that allows water to pass through and does not allow salt to pass through. One chamber is filled with salt water, the other with fresh water. "The resulting osmotic pressure can be very high," emphasizes Professor Paynemann. "It reaches about 25 bar, which corresponds to the water pressure at the foot of a waterfall that rushes down from a height of 100 meters."

Under such a high osmotic pressure, the water is fed to the turbine of a generator that generates electricity.

The main thing is the right membrane

It would seem that everything is simple. Therefore, it is not surprising that the idea of \u200b\u200busing osmosis as a source of energy originated almost half a century ago. But ... “One of the main obstacles at that time was the lack of membranes of the proper quality, - says Professor Payneman. - The membranes were extremely slow, so the efficiency of an osmotic electric generator would be very low. But in the next 20-30 years there were several technological breakthroughs. We learned today to produce extremely thin membranes, which means that their throughput has become much higher. "
Specialists of the GKSS Research Center made a significant contribution to the development of the very membrane, which has now made it possible to implement osmotic energy production in practice - albeit for the time being purely experimental. One of the developers, Carsten Blicke, explains: “The membrane is about 0.1 micrometers thick. In comparison, a human hair is 50 to 100 micrometers in diameter. It is this thinnest film that ultimately separates the seawater from fresh ".

It is clear that such a thin membrane cannot by itself withstand a high osmotic pressure. Therefore, it is applied to a porous, sponge-like, but extremely durable base. In general, such a partition looks like glossy paper, and the fact that there is a film on it cannot be seen with the naked eye.

Rainbow prospects

The construction of the pilot plant required an investment of several million euros. Investors willing to take risks, though not immediately, were found. Statkraft, one of the largest energy companies in Norway and a European leader in the use of renewable energy resources, volunteered to finance the innovative project. Professor Peinemann recalls: "They heard about this technology, were delighted and signed a cooperation agreement with us. The European Union allocated 2 million euros for the implementation of this project, the rest was contributed by Statkraft and a number of other companies, including our Institute."

"Several other companies" are research centers in Finland and Portugal and one of the Norwegian research firms. A pilot plant with a capacity of 2 to 4 kilowatts, erected in the Oslofjord near the town of Tofte and inaugurated today, is designed to test and improve the innovative technology. But the management of Statkraft is confident that in a few years, it will come to commercial use of osmosis. And the total world potential of osmotic energy production is estimated at no less than 1600-1700 terawatt-hours per year - this is about half of the energy consumption of the entire European Union. The most important advantage of such installations is their environmental friendliness - they do not make noise and do not pollute the atmosphere with greenhouse gas emissions. In addition, they are easy to integrate into existing infrastructure.

One fine day in 1747, the French abbot Nollet poured the recently half-drunk Bordeaux into a pig's bladder brought from the kitchen and immersed it in a barrel of water. 262 years later, on November 24, 2009, the Norwegian Crown Princess Mette-Marit sipped a glass of champagne. How are these two events connected? Both Nolle and the princess made remarkable discoveries. The Abbot was the first in the world to describe the phenomenon of osmosis and the basic properties of the membrane, and Mette-Marit, cutting a symbolic ribbon, opened the world's first osmotic power plant Statcraft in Toft.

Vladimir Sannikov

What the abbot, and also the great experimental physicist Jean-Antoine Nollet, actually filled in the history of the pork bubble, can be discussed. But the presence of water in both vessels (bubble and barrel) is undeniable. The difference is only in the concentration of the alcohol dissolved in it. It was this difference that gave impetus to the diffusion of water through the semipermeable membrane from the keg into the bubble. From the way the bubble swelled, one could understand that this phenomenon gives rise to a very significant unidirectional force, which Nolle called osmotic pressure. And he defined osmosis as the process of diffusion of a solvent from a less concentrated solution to a more concentrated one.

Today the Norwegian company Statcraft, the leader in the European clean energy market, has found a way to turn this pressure into electricity. The new technology is the only one capable of extracting joules from the natural difference in the content of mineral salts in fresh and sea water, and not from the kinetic energy of their movement. According to Norwegians, the world's resources of renewable osmotic energy range from 1.6 to 1.7 terawatts - about the same in 2004 it took a billion-dollar China! Unlike the capricious wind, surf and sun, the osmosis processes do not stop for a second, 24 hours a day all year round.

For the operation of an osmotic power plant, special engineering structures are not required: furnaces, reactors, dams, cooling towers. The world's first osmosis power plant is located in an empty warehouse in a wood processing plant.

Drink the sea

In fact, the phenomenon of osmosis has been used on an industrial scale for over 40 years. Only this is not the classic direct osmosis of Abbot Nolle, but the so-called reverse osmosis - an artificial process of penetration of a solvent from a concentrated solution into a dilute solution under the action of a pressure exceeding the natural osmotic pressure. This technology has been used in desalination and purification plants since the early 1970s. Salty sea water is pumped onto a special membrane and, passing through its pores, loses a significant proportion of mineral salts, and at the same time bacteria and even viruses. Pumping salty or polluted water requires large amounts of energy, but the game is worth the candle - there are many regions on the planet where the shortage of drinking water is an acute problem.

Theoretical developments in this area appeared at the beginning of the twentieth century, but for their implementation the main thing was lacking - a suitable osmotic membrane. Such a membrane had to withstand a pressure 20 times higher than that of a conventional domestic water supply and have an extremely high porosity. The creation of materials with similar properties became possible after World War II, when the scientific potential accumulated in the course of military projects gave impetus to the development of technologies for the production of synthetic polymers.

It is hard to believe that the difference in concentration of two solutions alone can create a serious force, but this is true: osmotic pressure can raise the sea water level by 120 m.

The most significant breakthrough in this area came in 1959. Sydney Loeb and Srinivasa Suranjan from the University of California, Los Angeles have developed a spiral anisotropic membrane capable of withstanding colossal pressure, effectively retaining mineral salts and mechanical particles up to 5 microns in size and, most importantly, having a high throughput at a minimum size. The invention of Loeb and Suranjan made osmotic desalination an economically viable business. In the early 1960s, Loeb built the world's first pressure retarded osmosis (PRO) desalination plant in Coaling, California, and then moved to Israel, where he continued his research with UNESCO funds. With the participation of Loeb in 1967, a desalination plant with a capacity of 150 m³ per day was built in the town of Yotvata, which produced clean drinking water from an underground lake with a salinity ten times higher than that of the sea. Three years later, PRO technology was protected by a US patent.

Osmosis and space

Membrane laboratory at the NASA Center. Ames has been dealing with the problem of providing the inhabitants of space stations with drinking water for many years in a row. Scientists have developed DOC technology, which combines two multidirectional processes - direct and reverse osmosis. In reverse osmosis, the membrane acts as a fine filter and requires a lot of energy. Direct osmosis, on the other hand, produces it. Each of these processes separately deprives aqueous solutions of an overwhelming amount of impurities. The result is so-called gray water that can be used for hygiene purposes. In order to make drinking water out of gray water, the solution goes through a membrane purification stage without additional heating and then purification from bacteria and viruses in the catalytic oxidation subsystem. The DOC energy density is low enough for space applications.
An original method of water purification for space stations was presented by the American company Osmotek. To collect waste products, she suggests using membrane bags like tea bags with activated carbon contained in them. The membrane allows only water with a small amount of contamination to pass out. This primary solution then enters the membrane chamber with a special concentrated substrate in another part. The emerging phenomenon of direct osmosis completes the process.
Oasys promises to reduce the energy consumption of osmotic desalination plants by no less than tenfold. True, in this case we are not talking about the opposite, but about direct osmosis. And not simple, but modified. Its essence lies in the presence of a patented pulling solution with a high content of ammonia, carbon dioxide and other chemicals on the counter side of a conventional PRO-membrane. When two solutions come into contact, the phenomenon of osmosis occurs and the raw material is purified from impurities. The highlight of the Oasys technique is that the stream of pure fresh water does not mix with the pulling solution.

Experiments on converting osmotic pressure into electrical energy using Loeb-Suranjan membranes have been carried out by various scientific groups and companies since the early 1970s. The basic scheme of this process was obvious: the flow of fresh (river) water, penetrating through the pores of the membrane, builds up the pressure in the reservoir with seawater, thereby allowing the turbine to spin up. The spent brackish water is then discharged into the sea. The only problem was that the classic membranes for PRO were too expensive, capricious and did not provide the required flow rate. Things got off the ground in the late 1980s, when Norwegian chemists Thorleif Holt and Thor Thorsen from the SINTEF Institute took on the task.

Cosmic sweep

Loeb's membranes required clinical cleanliness to maintain peak performance. The design of the membrane module of the desalination station provided for the mandatory presence of a primary coarse filter and a powerful pump that knocked debris off the working surface of the membrane.

Holt and Thorsen, after analyzing the characteristics of most promising materials, opted for inexpensive modified polyethylene. Their publications in scientific journals attracted the attention of experts at Statcraft, and Norwegian chemists were invited to continue the work under the auspices of the energy company. In 2001, the Statcraft membrane program received a government grant. The funds received were used to build an experimental osmotic facility in Sunndalsior for testing membrane samples and running the technology in general. The active surface area in it was just over 200 m².

In schematic images, the osmotic membrane is drawn as a wall. In fact, it is a roll enclosed in a cylindrical body. In its multilayer structure, layers of fresh and salt water alternate. The cross section shows how the water flows inside the osmotic cylinder are organized. The more such modules are installed at the station, the more energy it can generate.

To speed up the process, engineers from a specialized NASA membrane laboratory were invited to the team. The fact is that since the time of preparation for the Apollo lunar program at the NASA Center. Ames carried out in-depth studies of technologies for desalination and purification of aqueous solutions. The American experience came in handy, and by 2008 Statcraft had the first samples of spiral polyimide mebrans for future osmotic power plants. Their productivity was 1 W per 1 m² with a diffusion of 10 liters of fresh water per second at a pressure of 10 bar.

At the station in Toft, it is precisely such membrane modules with a total area of \u200b\u200b2000 m² that operate. For the generation of 4kW, this is quite enough, but for a full-fledged 25-megawatt station, it would take as much as 5 million squares. Of course, membranes for osmotic power plants should be much more efficient than current ones. Stein Erik Skillhagen, Statcraft's vice president overseeing the program, says the company is currently testing 3 W / m2 spiral hollow fiber samples, with 5-watt flat membranes expected by 2015. In addition, the Norwegians are closely studying third-party developments in this area and actively cooperate with specialists from General Electric, Hydranautics, Dow and Japan's Toray.

In Holland, 3300 cubic meters of river water is thrown into the salty sea every second. Scientists have calculated that its total energy potential is 4.5 * 10 9 W. Researchers from KEMA also intend to fish at least some of the energy from this bottomless barrel, but without unnecessary, in their opinion, mechanics. And such a possibility exists. So far - in the form of an experimental installation of reverse electrodialysis RED (reverse electrodialysis). It also uses sea and fresh water, separated by semi-permeable boundaries. Here are just two membranes, and they act as electrodes. After all, RED is a battery that works because of the difference in ion concentration in two media. This difference creates a weak voltage on the surface of the anode and cathode membranes. If you assemble a package from them, then the voltage will turn out to be very noticeable. For example, a battery the size of a standard shipping container produces almost 250 kW. KEMA has been operating a small 50 kW plant in Harlingen since 2006. It tests methods for cleaning and preventing membrane contamination with biomaterial. Clinical purity is critical to the efficient operation of a system.

By the way, a membrane for direct osmosis is not a thin wall, which is drawn in simplified diagrams, but a long roll enclosed in a cylindrical body. Connections to the body are made in such a way that in all layers of the roll, on one side of the membrane, there is always fresh water, and on the other, sea water.

Energy of the Depths

The difference between salinity (scientifically - salinity gradient) of fresh and sea water is the basic principle of operation of an osmotic power plant. The larger it is, the higher the volume and flow rate on the membrane, and, consequently, the amount of energy generated by the turbine. In Toft, fresh water flows by gravity onto the membrane; as a result of osmosis, the pressure of seawater on the other side increases sharply. Osmosis has a colossal power - the pressure can raise the sea water level by 120 m.

Further, the resulting diluted seawater rushes through the pressure distributor onto the turbine blades and, having given them all its energy, is thrown into the sea. The pressure distributor takes a part of the flow energy, spinning up the pumps that pump seawater. Thus, it is possible to significantly increase the efficiency of the station. Rick Stover, chief technologist at Energy Recovery, which makes such devices for desalination plants, estimates that the power transmission efficiency in the distributors is close to 98%. Exactly the same devices for desalination help to deliver drinking water to residential buildings.

As Skillhagen notes, ideally, osmotic power plants should be combined with desalination plants - the salinity of the residual seawater in the latter is 10 times higher than the natural level. In such a tandem, the efficiency of energy production will increase at least twice.

Construction work in Toft began in autumn 2008. An empty warehouse was rented at the Sódra Cell pulp mill. On the first floor, a cascade of mesh and quartz filters was arranged to purify river and sea water, and on the second, a machine room. In December of the same year, the membrane modules and the pressure distributor were lifted and installed. In February 2009, a group of divers laid two parallel pipelines along the bottom of the bay - for fresh and sea water.

Sea water is taken in Toft from depths of 35 to 50 m - in this layer its salinity is optimal. In addition, it is much cleaner there than at the surface. But, despite this, the station membranes require regular cleaning from organic residues clogging micropores.

Since April 2009, the power plant has been operated in a trial mode, and in November, with the light hand of Princess Mette-Marit, it was launched to its fullest. Skillhagen assures that following Tofte, Statcraft will have other similar, but more advanced projects. And not only in Norway. The underground complex, the size of a football field, is able to supply uninterrupted electricity to an entire city of 15,000 individual houses, he said. Moreover, unlike wind turbines, such an osmotic installation is practically silent, does not change the usual landscape and does not affect human health. And nature itself will take care of the replenishment of salt and fresh water in it.

A special membrane that allows water to pass through but does not allow salt molecules to pass through is placed between the two reservoirs. Fresh water is poured into one of them, salt water into the other. As such a system strives for equilibrium, the saltier water seems to draw fresh water from the reservoir. If a generator is placed in front of the membrane, excess pressure will rotate its blades and generate electricity.
The idea, as is often the case, was prompted by wildlife: according to the same principle, substances are transferred in cells - the same partially permeable membranes ensure the elasticity of cells. Osmotic pressure has long been successfully used by humans in the desalination of sea water, but it has been used for the first time to generate electricity.
At the moment, the prototype generates about 1 kW of energy. In the near future this figure may increase to 2-4 kW. In order to be able to talk about the profitability of production, it is necessary to obtain an output of about 5 kW. However, this is a very real task. By 2015, it is planned to build a large station that will generate 25 MW, which will supply electricity to 10,000 medium-sized households. In the future, it is assumed that ECOs will become so powerful that they can generate 1,700 TWh per year, as much as half of Europe now generates. The main challenge at the moment is to find more efficient membranes.
The game is definitely worth the candle. The advantages of osmotic stations are obvious. First, salt water (ordinary sea water is suitable for the operation of the station) is an inexhaustible natural resource. The Earth's surface is 94% covered with water, 97% of which is saline, so there will always be fuel for such stations. Secondly, the organization of an ECO does not require the construction of special sites: any unused premises of already existing enterprises or other office buildings will do. In addition, ECOs can be delivered at river estuaries where fresh water flows into a salty sea or ocean - in which case it is not even necessary to specially fill the reservoirs with water.

Fresh water + sea water \u003d energy source

Usually, where the river flows into the sea, fresh water is simply mixed with salt water, and no pressure is observed there that could serve as a source of energy. Professor Klaus-Viktor Peinemann from the Institute for Polymer Research at the GKSS Research Center in the town of Geesthacht in northern Germany, calls the conditions necessary for the osmotic pressure to develop: "If, before mixing, sea water and fresh water are separated by a filter - with a special membrane that allows water to pass through, but impermeable to salt, then the aspiration of solutions to thermodynamic equilibrium and equalization of concentrations can be realized only due to the fact that water will penetrate into the salt solution, and salt will not enter fresh water. "

If this occurs in a closed reservoir, then an excess hydrostatic pressure, called osmotic pressure, arises from the seawater. To use it for energy production, at the place where the river flows into the sea, it is necessary to install a large reservoir with two chambers separated from each other by a semi-permeable membrane that allows water to pass through and does not allow salt to pass through. One chamber is filled with salt water, the other with fresh water. "The resulting osmotic pressure can be very high," emphasizes Professor Paynemann. "It reaches about 25 bar, which corresponds to the water pressure at the foot of a waterfall that rushes down from a height of 100 meters."

Under such a high osmotic pressure, the water is fed to the turbine of a generator that generates electricity.

The main thing is the right membrane

It would seem that everything is simple. Therefore, it is not surprising that the idea of \u200b\u200busing osmosis as a source of energy originated almost half a century ago. But ... “One of the main obstacles at that time was the lack of membranes of the proper quality, - says Professor Payneman. - The membranes were extremely slow, so the efficiency of an osmotic electric generator would be very low. But in the next 20-30 years, there were several technological breakthroughs. We learned today to produce extremely thin membranes, which means that their throughput has become much higher. "
Specialists of the GKSS Research Center made a significant contribution to the development of the very membrane, which has now made it possible to implement osmotic energy production in practice - albeit for the time being purely experimental. One of the developers, Carsten Blicke, explains: “The membrane is about 0.1 micrometers thick. In comparison, a human hair is 50 to 100 micrometers in diameter. It is this thinnest film that ultimately separates the seawater. from fresh ".

It is clear that such a thin membrane cannot by itself withstand high osmotic pressure. Therefore, it is applied to a porous, sponge-like but extremely durable base. In general, such a partition looks like glossy paper, and the fact that there is a film on it cannot be seen with the naked eye.

Rainbow prospects

The construction of the pilot plant required an investment of several million euros. Investors willing to take risks, though not immediately, were found. Statkraft, one of the largest energy companies in Norway and a European leader in the use of renewable energy resources, volunteered to finance the innovative project. Professor Peinemann recalls: "They heard about this technology, were delighted and signed a cooperation agreement with us. The European Union allocated 2 million euros for this project, the rest was contributed by Statkraft and a number of other companies, including our Institute."

"Several other companies" are research centers in Finland and Portugal and one of the Norwegian research firms. A pilot plant with a capacity of 2 to 4 kilowatts, erected in the Oslofjord near the town of Tofte and inaugurated today, is designed to test and improve the innovative technology. But the management of Statkraft is confident that in a few years, it will come to commercial use of osmosis. And the total world potential of osmotic energy production is estimated at no less than 1600-1700 terawatt-hours per year - this is about half of the energy consumption of the entire European Union. The most important advantage of such installations is their environmental friendliness - they do not make noise and do not pollute the atmosphere with greenhouse gas emissions. In addition, they are easy to integrate into existing infrastructure.

Sustainability

Separately, I would like to note the absolute environmental friendliness of this method of generating electricity. No waste, no oxidizing tank materials, no harmful fumes. ECO can be installed even within the city without causing any damage to its inhabitants.
Also, the operation of the ECO does not require other sources of energy to start and does not depend on climatic conditions. All this makes ECO an almost ideal way to generate electricity.