Russia, a country full of rivers, washed by the seas, belonging to the basins of the three oceans, has an almost inexhaustible prospect in the field of hydropower. The electricity market here and in the world is constantly growing – the only question is how to turn the energy of water into electricity in such a way that the price of it is competitive relative to that, obtained by traditional methods.
TIDAL POWER PLANTS
In theory, it would be more correct to call them lunar. The natural satellite of the Earth, approaching our planet, sets in motion the waters of our world, thus causing a tide; the sun, by the way, also participates in this process. For this reason, for the operation of a tidal power plant, third-party energy is not required: as long as its generator with the substation is intact, it will work. In this case, even in the event of cataclysms and military actions, its destruction is not followed, for example, by a spill of radioactive coolant or other harmful substances: there is simply no such at Hydroelectric Plant ( PES). Power plants of this type are much more gentle also to the fish wealth of the country: when passing through their water intakes, not more than ten percent of plankton, the main food of fishes, is lost – whereas in the case of hydroelectric plants using turbines, passing through its blades, almost the entire microfauna is destroyed. In addition, all damage done to river bed, which are fraught with the construction of PES, are restored naturally in a couple of years with the complete restoration of the hydrobiosphere. And, finally, neither the ice conditions, nor the salinity of water at the work of such power plants have any effect.
The minimum depth difference at which PES is capable of operating is 4 meters. Of course, with the ebb and flow, the movement of water through the turbine screw will have different directions. The intensity of rotation also depends on the level of the working fluid in the energy-accumulating basin. The generator shaft completely stops at the two “dead” points, which limit the duty cycle. Rotation starts only when a difference in levels occurs, whether positive or negative.
Here is how the principle of the operation of such stations is described by Evgeny Malyar in his article on PES: “The greatest amplitude of sea level is observed in the sea bays, in which natural semi-enclosed basins are formed by the coastal relief. The change in the direction of rotation of the turbine is technically realized by means of a variable pitch of the blades, in other words, by their rotation relative to the axis of rotation. Typically, turbines have the ability to switch from generator to pump mode, depending on the situation and the phase of the process cycle. The main disadvantage, which is the uneven performance, is offset by a common unified power system, part of which are tidal power plants. “
The first and only PES in Russia remains the Kislogub tidal power station built in 1968 in the Kislaya Bay of the Barents Sea. It is built near the village of Ura-Guba, where the height of the tides exceeds the mark of four meters. The Kislogubskaya PES, which worked until the middle of the 1990s, was preserved and later, already at the beginning of the new millennium, thoroughly modernized and re-commissioned, as an experimental site for the needs of the future construction of more powerful tidal power plants. One of these, with a capacity of 12 megawatts, is planned to be built in the Murmansk region. The power of the Kislogubskaya TPP is small: it is 1.7 megawatts, which allows maintaining the energy supply of the village with five thousand inhabitants.
There is a project for the construction of the Penzhinskaya TPP in the Penzhina Bay of the Sea of Okhotsk, where the height of the tides reaches a mark of 8 meters. However, neither the timing of the implementation of this project, nor the sources of its funding is yet clear.
Approximately the same situation arose with the construction of the Mezenskaya TPP in the Mezenskii Gulf of the White Sea, which could generate up to 39 million kW / h of electricity, taking into account the almost eight-meter height of the local tides. Ten years ago in Mezensky gulf the PES power plant on a floating platform was tested, but its capacity was only 1.4 kilowatts.
The maximum height of tides in Russia – more than 8 meters – is observed in the Shantar Islands in the Sea of Okhotsk, which allowed the inclusion of the project of the Tugur tidal power plant in the long-term state program for hydropower development. If the project is successfully implemented, the capacity of the Tugurskaya TPP can reach 11 GW, which is significantly higher than, for example, the well-known Sayano-Shushenskaya HPP.
If the tidal power plants can be said to be immaculate in terms of ecology, why are there only a little more than a dozen of them in the world (only two of them, Sikhwa in South Korea and the French La Rance, produce about 250 MW of energy? the rest of the existing PET ranges from 300 kW to 20 MW)? The whole issue is in the high cost of their construction: on average, the PES costs one and a half times more than the HPP of the same capacity. Nevertheless, in the world there is a tendency to a stable growth of tidal energy – and its experts estimate the total potential at 1,000,000 megawatts.
WAVE POWER STATIONS
These floating facilities generate electricity, using the virtually inexhaustible energy of the waves in the world’s oceans – therefore, the potential of this alternative energy sector is estimated at no less than two million megawatts – that is, to be more understandable, comparable to a thousand nuclear power plants working at full capacity.
Wave power stations use, firstly, kinetic reserves – a wave, passing through a large diameter pipe, rotates the blades, and they transmit the force to the power generator. They can work differently: in this case, water, penetrating into the special chamber, displaces oxygen from there, which is redirected along the channel system and rotates the turbine blades. And, finally, these plants are able, in the role of floats, to use rolling energy – each of them, moving in space along with the wave profile, makes a turbine rotate by means of a complex system of levers.
Like the tidal power plants, the wave farms have one significant drawback: a high price, which is due to the complexity of the structure. In particular, its problematic place is the transfer of the received electricity through the wires to the consumer. The often expressed fears that the wave farms can allegedly place gas exchange in the world’s oceans and the process of purification of its surface, in geopardy are likely to be untenable: even if humanity completely transfers to wave energy, the area occupied by floating power stations will be scanty with respect to the total area of the world’s oceans. For the same reason, skepticism also causes judgments that an excess of wind farms can slow the rotation of the earth, because of which waves are formed. It is hardly reasonable and conjecture that wave energy can become an obstacle to shipping and fishing – to avoid this, it is sufficient to determine the location of the wind farm away from sea routes and fishing areas.
No matter how expensive the wave power plants are, they generate electricity almost at zero cost – besides they are able to protect coastal structures from the destructive effects of waves. In general, the advantages of these power plants are much greater than the disadvantages. Therefore, further development of the wind farm network is primarily due to the reduction in their cost by using the latest technologies and materials. This is also necessary because the majority of modern wave farms are calculated based on the power of the waves in the range of 75-80 kW / m. However, in the storm this indicator is much higher, and in order to avoid damage to the blades and the plants themselves, developers have to take care of appropriate technical solutions to this problem in advance.
The world’s first wave farm was launched in 1985 in Norway. In fact, it was only an experimental model capable of generating 500 kilowatts of energy. Twenty years later, the first industrial wave power plant was commissioned in Australia (by the way, both wave and tidal power stations are used in this country). And the world’s first commercial wind farm and the largest of this kind of facilities to this day earned in Portuguese Agusador in 2008. In addition to its rather high power – 2.25 MW – it has a characteristic feature: a modular design that allows adding or removing sections.
The only project of this kind in Russia so far was implemented in 2014 in Primorsky Krai. Its development was jointly carried out by scientists of the Ural Federal University and the Pacific Oceanological Institute. Domestic wave generators are alternative transformers of the energy of sea currents, tides and waves into electricity. The installation is of an experimental nature. Its first tests in the water area of the Cape Shultz station demonstrated its considerable potential, but at the same time they identified a number of problematic areas, in particular, the already mentioned deformation of the blades during the storm. At the same time, it became evident that such installations are able to protect the coastal zone from blurring, and the shore from erosion. In the future, sea drones and analogues of automatic coastal border protection systems can be based on them.
SMALL HYDRO-POWER STATIONS
It is not necessary to speak about the industrial use of mini and micro hydroelectric power stations: the power of both is up to 100 and up to 1000 (according to some classifications up to 3000) kilowatts, respectively. At the same time, such power plants can serve as sources of almost free electricity, which is especially important due to the constant increase in tariffs. One such station, depending on its capacity, is able to provide electricity to a detached house or even a small village. From solar panels and wind generators, they are favorably distinguished by the ability to produce stable energy, regardless of environmental conditions.
The simplest in terms of creation and installation among small hydroelectric power stations are flowing, not requiring a dam construction. After all, the construction of the latter is a rather complicated matter, requiring coordination with local authorities and neighbors.
Flowing micro-hydroelectric power stations can be a water wheel equipped with blades and installed perpendicular to the water surface. There are modifications to the water wheel with special blades optimized for the flow of liquid.
Rotary micro-HPPs are a cable stretching from one bank of the river to another, on which rotors, immersed in water, are strung like beads. The rotation of the rotors is transferred to the cable, one end of which is connected to the bearing, and the other end to the generator shaft.
The Daryer Rotor is a vertical rotor, rotated by the difference in pressure on its blades, which is created by the flow of complex surfaces around the liquid. The effect in this case is similar to the lifting power of hydrofoil vessels or the lift of an aircraft wing. At the beginning of work such a rotor should be untwisted. The advantage of this design is that the axis of the rotor is located vertically, which allows the selection of power over water. In addition, the Darjeer rotor will rotate in any direction of the flow.
The design in the form of a propeller is an underwater “windmill” with a vertical rotor. The width of the blades of such a propeller is small – it rarely exceeds two centimeters, which ensures a minimum resistance and maximum possible speed at a flow rate of up to 2 meters per second.
The design of mini hydroelectric power plants, as a rule, includes a water intake device, a power unit and control elements. Some of them use the energy of free flow of rivers, others – water level changes at different water management facilities. Mobile mini-HPPs are mounted in containers and use pipes and flexible armored sleeves as pressure derivations. Channel and dam-type mini-hydroelectric power plants with small reservoirs are much more complicated than others in the process of construction: they can be built only by a team of qualified specialists.
Concluding the conversation about alternative hydropower in Russia and in the world, we note that in this article we have touched only the most common and, at the same time, promising structures of this type. Besides them, of course, there are others. For example, waterfall power plants in which water, falling down, turns the turbine blades.
In Russia they did not receive special distribution because of the peculiarities of the landscape of our country. A fundamentally new word in alternative hydropower is osmotic power plants – they are located at the confluence of the river in the sea and receive energy from the movement of particles when mixing salty and fresh water. To this day in the world operates only one such power plant. Located in Norway, it has the status of an experimental laboratory, whose employees are working on a number of issues, including the economic payback of objects of this kind.