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...with the modern development of nautical architecture and marine engineering, it appears it is quite possible to use those natural power reserves which, until recently, seemed inaccessible from both technical and economic points of view.
Akademician V.V. Shuleykin
It is more and more obvious to Mankind that reserves of mineral raw material on continents are becoming exhausted, and energy produced by modern power stations are not endless. It is not surprising, therefore, that there is a great interest in the Ocean, which contains a huge thermal and mechanical energy budget which, if transformed into electricity, promises to generate great benefits. Now, all industrially-developed countries of the world are using the energy of the Ocean in some form or another.
Various installations using power resources of the Ocean
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1. Thermal power
station in Arctic latitudes 2. Wave-power installation 3. Installations working on energy produced by currents 4. Thermal power station in tropical latitudes 5. Wind power installations 6. Plants for processing seaweed for fuel 7. Power station using salinity gradients (energy produced by osmosis) 8. Tidal power station |
The problem of providing electricity to many parts of the World economy, which is
continually expanding to meet the needs of the more than 5 billion people on Earth becomes
more and more critical.
The basic, modern power installation is operated by the generation of heat or by water power. However, power-plant development is impeded by a number of factors. The cost of coal, petroleum and natural gas, which are the fuels most consumed at thermal stations, continues to grow, and the resources of these kinds of fuel are being depleted. Furthermore, many countries do not have their own fuel resources and/or use them inefficiently. Power resources in developed countries are used almost completely used up because the majority of river sites suitable for hydraulic engineering construction are already in use. The solution to this problem was seen in development of nuclear engineering. At the end of 1989, more than 400 nuclear power stations (NPS) were in operation. Today, however, NPS are not considered as a source of cheap and ecologically safe energy. The fuel for NPS is uranium ore, an expensive and labour-consuming raw material, of which reserves are limited. Furthermore, construction and maintenance of NPS are coupled with large difficulties and costs.
Only few countries now continue to build new NPS, improving their machinery and maintenance. The serious drawbacks to further development of nuclear power plants are the problems of reliable maintenance for trouble-free operation and the greater problem of what to do with the spent radioactive fuels and their effects on the environment.
Studies on the use of Oceanic energy resources of the Ocean relating to "renewable energy resources" were begun in the middle of our century.
The Ocean is a large accumulator of solar energy, which is transformed into the energy of currents, water and atmospheric temperature and winds. Tidal energy is the result of the tide-producing forces of the moon and the Sun.
Although the power resources of the Ocean are lesser than the hydro-electric resources of the land, they represent a great value since they are continuously renewed and practically inexhaustible. Experience in using already operational systems has Design of future systems will continue to include careful investigations regarding their impact on the environment.
Thermal resources
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1. Isotherms in
the Ocean at the surface and at a depth of 1000 m 2. 1,000 m isobath 3. Water temperature differences in degrees C 4. Experimental Ocean thermal-electric Ocean power stations 5. Projecting Ocean thermal-electric power stations |
Amount of energy (in kilojoules) in one m3 of water:
Water temperature differences in degrees C |
kilojoules in one m3 |
Water temperature differences in degrees C |
kilojoules in one m3 |
15 |
820 |
20 |
1380 |
16 |
920 |
21 |
1510 |
17 |
1030 |
22 |
1650 |
18 |
1140 |
23 |
1800 |
19 |
1260 |
24 |
1960 |
The concept of using thermal energy accumulated by tropical and subtropical Ocean waters was first advanced at the end of the 19th century. The first attempts at implementation were made in the 1930s and also showed practicality of this idea. In the 1970s, a number of countries began designing and building experimental Ocean Thermal Power Stations (OTPS), which were large and complex facilities. An OTPS can be built on the coast or on the Ocean (on anchored systems or in a free-drift mode). The operation of an OTPS is based on the principle used in the steam engine. A gas cylinder is filled with Freon or ammonia, which are fluids which boil at low temperatures, and then washed by warm surface waters. The gasses formed by the process rotate the turbine connected to the electricity generator. Spent gas is cooled by water from underlying cold layers and, when condensed into a fluid state, are recirculated in the boiler. An OTPS has a power-generation rating of 250 - 400 Megawatts.
Scientists from the Pacific Oceanological Institute of the USSR Academy of Sciences have put forward an original idea for producing electrical energy using temperature differentials: temperature differences between under-ice sea water and surface air in Arctic regions can vary by 26°C and more.
In comparison with conventional thermal and nuclear power stations, OTPS are considered by experts to be more cost-effective and practically non-polluting to the Ocean environment. The recent discovery of hydrothermal sources at the bottom of the Pacific Ocean gives rise to attractive idea of creation of underwater OTPS, utilising the temperature differential between source- and ambient
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1.Ventilating channels 2.Living accommodation 3.Ammonia storehouse 4.Warm water supply 5.Replacement of cold water 6.Replacement of warm water 7.Condenser 8.Turbine 9.Replacement of cold water |
In the USA, an experimental OTPS construction design for generating 125 MW has been conducted. The diameter of the working unit of the station is 104 m, the height is 52 m, and it has a draught is 32 m. The fibreglass, plastic-reinforced pipeline for drawing cold water is 1,200 m long and 15 m in diameter.
One method for transmission of electrical energy from an onshore ocean thermal power
station (OTPS)
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1. A floating power installation 2. Rope 3. Anchors 4. Cold water supply pipe 5. Cable 6. Underwater buoy 7. Connective coupling 8. Near bottom cable 9. Building a station |
An installation site of an OTPS in a depth of more than 1,000 m. It is thought that OTPS-generated electrical energy will be carried through an underwater cable (for distances of up to 250 miles), or will be used on-site to extract hydrogen from water and nitrogen from the air, thereby synthesising ammonia. Oil tankers will be used to export this product. The resulting hydrogen can serve as a fuel for marine vessels.
A Japanese experimental OTPS, using surface water with a temperature 29.8° C and deep waters with temperature 8.1° C, operated on the island of Nauru (Pacific Ocean) between 1980 and 1982. The cold water moved from a depth of 580 m through a polyethylene pipeline with a diameter of 70 cm. The maximum power output of the station is 120 kW. The useful power is 31 kW. The design trials for an OTPS generating 10 MW of power was begun as a result of the tests from this station.
Comparing Tropical and Arctic Ocean thermal power stations (OTPS)
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1. Tropical OTPS 2. Arctic OTPS |
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1.Turbines for electricity
generation 2.Vapours 3.Condenser 4.Fluid (Freon) 5.Gas-generator 6.Solar heater 7.Cold water pump 8.Replacement of cold water 9.Replacement of warm water 10.Warm sea water pump 11.The mixer |
In coastal regions of tropical islands, the cold water supply for a high-energy OTPS is carried by a special pipeline. Replacement of mixed cooled water is done by means of another pipeline in intermediate layers of the Ocean. During daytime hours, additional heating is accomplished by solar heating, thereby considerably increasing power generated by the station.
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1. Gas-generator 2. Freon gas 3. Turbo-generator 4. Condenser 5. Sprayer 6. Pumps |
A scheme for an Arctic OTPS was developed by the Pacific Oceanological Institute of the USSR Academy of Sciences and the Institute of Problems of Marine Process Engineering. Freon gas is contained in the gas-generator over which sea water passes, and then proceeds to enter the turbine and then the condenser. Cooling of the condenser is accomplished by a solution of calcium chloride, which, in turn, is cooled by air. These institutes have also developed other similar types of high-power energy installations.
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1. Air 2. Electrodes 3. Condenser 4. Pipe to sprayer 5. Evaporator 6. Ioniser 7. To generator |
In 1982, an Arctic OTPS was invented and tested in the USSR. Freon circulating in a ring-shaped tube moved along an inclined pipe to a sprayer, where ionisation of droplets occurred instead of producing high voltages The droplets were transferred with the gas, forming electrically-charged particles which were stored on the transmission-generation, forming 10 kW of voltage.
Duration of the use of Ocean thermal resources of the Russian Arctic and Far East
Regions
>180 - Number of days in one year with a temperature differential between water and air of more than 10°C
The use of tidal energy began in the 11th century and was used for the operation of grain and sawmills on shores of White and North Seas. Presently, similar facilities serve the inhabitants of a number of coastal countries. Now, research for the creation of tidal power stations (TPS) are conducted in many countries of the World.
Tidal power stations work on the following principle: in a river mouth or bay, an earth-dam is created. A tidal pool is created behind the dam, which is filled by an incoming tidal current passing through turbines. When the tide ebbs, the outflowing water from the pool runs back to the sea, turning the turbines in the opposite direction. Construction of a TPS in regions with tidal oscillations of not less than 4 m is considered economically efficient. The full capacity of a TPS depends on the characteristics of the tidal bore in the region of the station, the volume and area of the tidal pool from the number of turbines installed in the dam. In some projects, two or more pool design schemes are used to balance electric energy development.
With the creation of special capsule turbines, which are operational in both directions, new capabilities now exist to increase the efficiency of TPS for a unified power system of region or country.
When the time of inflow or outflow coincides with the period of the greatest consumption of energy, a TPS works in a turbine mode, and when the of time of inflow or outflow coincides with the least consumption of energy of the turbine, a TPS can go off-line or work in a pump mode, filling the pool higher than the level of maximum inflow, or by draining of the pool.
Operational and tidal power stations (TPS) in the design stage
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1. Operational
TPS 2. Designed TPS |
The main characteristics of tidal power stations (TPS)
¹ |
Operational sites and future TPS |
Average high tide, m |
Power, MW |
1 |
Cook Inlet | ||
| Knik-Arm | 8,4 |
1440 |
|
| Turnagain-Arm | 8,4 |
900 |
|
2 |
Rio Gallegos | 7,6 |
700 |
3 |
Golfo de San Jorge | 4,2 |
- |
4 |
Bahia Sao-Jose | 5,6 |
7000 |
| Golfo-Nuevo | 3,6 |
11000 |
|
5 |
Belem | 5,9 |
30 |
6 |
Bay of Fundy | ||
| Cumberland Bay | 9,9 |
1080 |
|
| Cobequid Bay | 11,8 |
4030 |
|
| Shepody Bay | 9,6 |
1550 |
|
7 |
Annapolis-Royal (1984) | 6,4 |
20 |
8 |
Ungava Bay | ||
| 9 dam sites | 7,7 |
9260 |
|
9 |
Severn River | 8,3 |
7200 |
10 |
Strangford-Lough | 3,0 |
320 |
11 |
Solway-Firth | 5,1 |
6830 |
12 |
River Rance* (1966) | 8,5 |
240 |
13 |
Chausse de Sein | 8,5 |
12000 |
14 |
Cotentin Peninsula | 8,0 |
50000 |
15 |
Kislaya Guba (1968) | 2,3 |
0,4 |
16 |
Lumbovskiy Bay | 4,2 |
670 |
17 |
Mezenskiy Guba | 6,0 |
15200 |
18 |
Guba Penzhinskaya: | ||
| south range | 6,2 |
87400 |
|
| north range | 6,2 |
21400 |
|
19 |
Tugurskiy Bay | 4,7 |
10300 |
20 |
Inchon | 6,0 |
500 |
21 |
Tsien-tien (1980) | 5,0 |
3 |
22 |
Gulf of Cambay | 6,8 |
7360 |
23 |
Gulf of Kachchh | 5,3 |
1600 |
24 |
Walcott Inlet | 5,0 |
1250 |
25 |
Security Bay | 5,6 |
570 |
* Operating TPS, in brackets - year of commissioning
Transporting the floating building of Kislogubskaya TPS
General view of Kislogubskaya TPS
Upon construction of the experimental Kislogubskaya TPS, the original engineering
design was accepted, thereby avoiding the construction of an expensive dam with hydraulic
turbines built into it. The idea consisted of making a simple, yet strong floating
building for the station, which was capable of sustaining sea transport to an operational
site and consequent operation under the pressure of tidal flow. The building of this TPS
was constructed in Murmansk and towing vehicles transported it to Kislaya Guba, where it
was lowered on a previously prepared site for which the beforehand prepared basis, for
which the special structure of hydraulic engineering concrete was developed. To protect
the TPS from corrosion and fouling, a special system of electro-chemical plating and
painting was developed.. Kislogubskaya TPS supplied the first electric power to the Kola
Peninsula. The average annual output of the electrical energy generator is about 30
millions KW/H.
The experience of construction and maintenance of Kislogubskaya TPS fostered the construction of other electrical power stations. Prospective activities in Penzhinskaya Guba of the Sea of Okhotsk are now being conducted. Two types of dams TES dams are being built:: in southern range, 72 km long, and in northern range, 32.2 km long. From tentative estimations of the Hydroproject Institute, the power generated by the first TPS version will be 87,400 MW/sec., and in the second version, 21,400 MW/sec. In building of the TPS dam, 320 working units will be connected by first floating them into place, and connecting them with sophisticated hardware. In the dam and tunnel inside the station, there will be a motorway which will connect the Kamchatka Peninsula to continent. In a southern part of the Sea of Okhotsk it is possible to build a 37-kilometre-long dam across Tugurskiy Gulf and to construct a TPS generating 8,000 MW.
Cross-sectional view and principle of operation of Penzhinskaya TPS
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1 - Tidal current
into pool 2 - Tidal current from pool 3 - Turbine 4 - Machine hall 5 - Transport tunnel |
In 1966, France built the World’s first tidal power station on the river Rance, in the process constructing 24 earth dams which generate approximately 502 millions KW/H of electrical power/year. Tidal capsules were placed in the earth dams, permitting three direct and three return modes: generator, pump and valve that provides effective maintenance of the TPS. Evaluations by experts conclude that TPS Rance is economically justified. The annual costs of maintenance are lower, than for water-powered plants and have resulted in a 4 % recovery of the initial capital investment at the time of this writing.
Annual production of electrical energy by the Rance tidal power station
Electricity production, millions KW/h 1 - in the pumping mode 2 - in the turbine mode
The tidal dam TPS Rance
1 - Connector shaft; 2 - Steel-reinforced concrete extensions for attaching the cover of the capsule to the base in the concrete water tunnel; 3 - metal cover bringing a water to the turbine; 4 - stationary vanes in the turbine; 5 - rotary, moving vanes; 6 - fairing; 7 - ventilator; 8 - generator; 9 - shaft; 10 - driving wheel
Cross-sectional view of the building of TPS Rance
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1. Pool 2. Hydroelectric generating set 3. The sea |
Power of waves of the World Ocean
Average annual power of waves in kW / m
The concept of generating electricity from Ocean waves was first explained in 1935 by the Soviet scientist K.E. Tsiolkovskiy.
Wave power stations operate on the principle of converting mechanical energy produced by wave motion into electrical energy and the present use of these generators is to power floating remote sensors, etc.
Wave-powered generators are presently used for power supplies of autonomous buoys, beacons and scientific devices. As a side-use, sufficiently large wave energy electrical generators serve as wave protection for drilling platforms, open harbour approaches and for power in mariculture facilities. The industrial use of wave energy has already begun. There are already about 400 beacons and navigational buoys that receive their power from wave generators. In India, wave-energy powers the energy the floating beacons of the port of Madras, and in 1985, Norway became the first country to operate an industrial wave station, which generates 850 kW.
The creation of wave power stations is determined by selecting the best location of an Ocean area which has a fairly steady reserve of wave energy, effective design of station, in which hardware can smooth irregularities from storms. It is considered that effective wave stations can produce about 80 kW / m. Experience in using existing installations has shown that the electricity output, while 2-3 times more expensive than conventional methods is expected to show a significant lowering of costs in the future.
In wave installations with air-pressure converters, the air flow periodically changes or reverses its direction. For these conditions, the Wells turbine was developed, the curve of which smoothes the operation, thereby maintaining a constant direction of the rotation when the air flow changes, and therefore, maintains a constant speed and direction of rotation of the generator. The turbine has found broad application in various wave-energy installations.
Solter Duck
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1.Generator 2.Float |
A project called the “Solter Duck” is a wave energy converter. The
working model has a float ("duck"), the profile of which is calculated under the
Laws of Hydrodynamics. In this project, a large number of large floats, sequentially
fastened on a common shaft is put in place. Under wave action, the floats come in motion
and are restored by the force of their own weight. The pumps inside the shaft are filled
with a special fluid and are activated. Through a system of pipes of various diameter the
residual pressure rises, activating the turbines installed between floats and elevated
above the sea surface. The electricity produced is sent to shore via an underwater cable.
For more effective distribution of loads on the shaft, it is necessary to install 20-30
floats.
In 1978, a 50 m long model of the design was tested, consisting of 20 floats, one meter in
diameter. The power output was 10 kW.
A higher output project using 20-30 floats, 15 meters in diameter and fastened to a 1,200
meters-long shaft was developed. Estimated power output of this installation is 45 ,000
KW.
Similar systems installed on the western shores of the British Isles are capable of
supplying the electricity demands for Great Britain.
A wave raft
The design of a wave raft was patented for the
first time in the USSR in 1926. In Great Britain, tests of experimental models of ocean
power stations were conducted in 1978, providing a similar solution. Cockerel’s Wave
Raft consists of jointed sections, the movement of which is transmitted to pumps with
electrogenerators. The entire structure is kept in place by anchors. A three-sectional
Cockerel Wave Raft, 100 meters long, 50 meters wide and 10 meters high can produce up to
2,000 kW of electrical power.
A model of a wave raft was tested in the USSR in the 1970s in the Black Sea. It was12
meters long, and the width of the floats was 0.4 meters. On waves 0.5 metres high and
10-15 meters long, the installation developed 150 W of power.
In 1985, an industrial wave energy station was constructed 46 km north-west of Bergen, Norway It consisted of two installations. The first installation, on the island Toftestallen worked on an air-pressure principle. A steel-reinforced concrete chamber was poured in a tunnel drilled in the underlying rock, with a 12.3 metres-tall steel tower having a diameter of 3.6 meters built above the tunnel. The waves poured into the tunnel, creating a significant change in the volume of air. The rising air flow through a system of valves caused the rotation of a turbine and generator, producing 500 kW of electricity, which, translates to 1.2 million KW / hours. A winter storm at the end of 1988 destroyed the tower. A new tower was built of steel-reinforced concrete.
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1. Building of
power station 2. Dam 3. Containment basin 4. Narrowed-down channel 5. Tower |
The design of the second installation consists of a cone-shaped channel in a gorge that is 170 metres long, 55 meters wide and 15 metres high, and is built in a channel between islands and separated from the sea by dams holding the power generators. Waves conducted through a narrowing channel, increase their heights from 1.1 to 15 m, and flow into a 5,500 m3 basin, which is 3 m is higher than the sea level. From the basin, the water passes through low-pressure turbines, generating 350 KW of power. The annual output of the station is up to 2 millions KW /h of electricity.
The wave power installation, "Kaimai" ("Marine
Light"), is the highest output power station using air-pressure converters. It was
constructed in Japan in 1976. It uses the energy produced from waves up to 6 - 10 m high.
Built on an 80 metres-long barge that is 12 metres wide, and which has a displacement of
500 tons, it holds 22 air chambers opened from below, with each pair of chambers works
operating one Wells turbine. The average power output is about 1000 KW. The first tests
were conducted in 1978 - 1979 near the city of Tsuruoka. Electricity was transmitted to a
shore via a 3 km-long underwater cable.
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1. Wells Turbine 2. Soft chamber |
In Great Britain, the “Mollusc” wave-power installation was
developed, which worked similar to the organs of a mollusc, that is, in two connected
chambers (one of which is soft and contains pressurised air just a little higher than the
surface atmospheric pressure). When waves hit the soft chambers they are compressed and
the closed air flow from the soft chambers goes into the hard section of the installation
and then the soft chamber relaxes. Wells air turbines with electricity generators are
placed inside the path of the air flow.
The experimental floating installation contains 6 chambers, placed on a frame 120 m long
and 8 m high. The expected output is 500 kW. Further developments have shown that the
greatest effect is derived chambers arranged in a circle. In Loch Ness (Scotland), an
installation consisting of 12 chambers and 8 turbines, placed on a frame 60 m in diameter
and 7 m high was tested. The theoretical power output of such an installation is up to
1,200 kW.
Wind energy
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1. Isolines of
wind energy in thousand kWh/year 2. Energy of wind in thousand kWh/year |
The use of the wind energy has a centuries-old history. The idea of transforming wind power into electricity arose at the end of the 19th century. In the USSR, the first wind-driven power station (WPS) with a power rating of 100 KW was built near Yalta in the Crimea in 1931. At the time, it was the largest WPS in the World. The average annual output of the station was 270 MW hours. The station was destroyed in 1942.
During the energy crises of the 1970s, the interest in using the power of the increased. The development of WPS, both for the coastal zone, and for the open ocean began. Ocean WPS are capable of producing more energy than ones located on land, because winds above the ocean are stronger and more constant.
Construction of low power WPS (from hundreds of watts up to tens of kilowatts) as a power supply for seaside settlements, beacons and sea water distillation plants is considered expedient when the average annual wind speed is 3.5-4 m/s. Exponentially, high-power WPS (from hundreds of kilowatts up to hundreds of megawatts) for the transmission of electricity to a central power system is economically feasible when the average annual wind speed exceeds 5.5 - 6 m/s. (The power, which can be received from one m2 across the air-flow, is proportional to the wind speed in the third degree).
Denmark, one of the leading countries of the world in area of wind-produced electricity, already has 2,500 wind-powered electrical installations producing about 200 MW.
On the Pacific coast of the USA, (in California), where the wind speed averages 13 m/s over the long term (more than 5,000 hours/year), there are already a few thousands high-power wind installations. WPS of various energy capacities are in use in Norway, Netherlands, Sweden, Italy, China and Russia, and others.
In connection with varying wind speeds and directions, a great deal of attention has been given to building wind installations to produce electricity for central power systems. Energy produced by large, Ocean WPS is expected to be used to produce hydrogen from ocean water, or for extracting minerals from the sea floor.
At the end of the 19th century, a wind-powered electric motor was used by F. Nansen on the vessel "Fram" for producing light and heat for the participants of a polar expedition during a long period of drifting in ice.
Two-bladed wind turbine outputting 100 kW of electricity (USA)
In the state of California on the Pacific coast of the USA, the
World’s largest grid for testing wind energy installations (WEI) exists, which used
designs developed in the USA, Great Britain Germany and Denmark.
Located east of San Francisco in the Altamont Valley, 17 models of turbines with
horizontal rotational axes are being tested, and 2 vertical-axis turbines as well, with
blade diameters of from 10 to 45 m, capable of generating from 10 to 750 kW. At the
beginning of 1989 the WEI group included more than 17,000 turbines generating 1,500 MW of
electrical power.
On a special grid 8 km from San Francisco, there are 75 Hauden wind turbines producing 330
kW of electricity. The heights of the towers reach 25 m, and the diameter of the blade
rotor is 31 m.
There is a project of wind energy installations underway, which is supposed to be placed at shallow depths (up to 10 m). The energy output will be used to extract petroleum and natural gas. In Norway, the project will provide for the installation of 18 groups on each of 10 platforms developing an average power output of 900MW.
A “wind dam” of the future, which is a project is offered by Soviet scientists, is an anchored, floating metal frame with wind propellers. The advantage of the project is that the wind propeller takes the wind from the most efficient direction.
Hauden wind energy installations (Great Britain)
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1.Anchors 2.Low pressure turbine 3.Generator 4.Height of fall 5.Wave energy converter 6.Wind energy converter |
Coastal power station, using wind and wave power
The strongest Ocean currents are a potential power source. The present state of engineering allows for electrical production from currents having a flow-velocity of more than 1 m/s. Therefore, power from one m2 across the current flow produces about 1 KW. Strong currents, such as the Gulf Stream and Kuroshio, respectively transport 83 and 55 million m3/sec of water, at speeds of up to 2 m/s, and the Florida Current, 30 million m3 - with a speed up to 1.8 m/s. These currents can be used effectively to produce electricity.
The currents in the Straits of Gibraltar, La Manche (English Channel) and the Kurile Islands region are of interest for ocean power engineering. However creation of ocean power stations using current energy has a number of technical difficulties, primarily that large, floating power stations present possible hazards to navigation.
Power resources of currents
|
1 - Power potential of the strongest currents in MW/km2 |
An anchored, floating power station. The current actuates paddle turbines with horizontal rotation axes located on the vessel’s anchor, which is oriented in the direction of current.
Using rather weak currents, the working apparatus is a parachute system. The diameter of the parachutes can reach 100 m, and the length of the cable to which they will be attached may be as long as 18 km. The parachute system passes through a pulley on a vessel resting at anchor. The parachutes are uncovered in the current direction and open against the current The energy output is sent to the shaft of an electric generator.
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1.The generator 2.Curl of the turbine 3.Body, ensuring a buoyancy of the turbine I.Turbine II.Anchor III.Underwater electricity transmission cable |
The program "Coriolis" will be installed in the Florida
Strait, about 30 km east of the city of Miami, and will have 242 turbines with two
drive-wheels 168 m in diameter, rotating in opposite directions. The pair of drive-wheels
is placed inside a hollow aluminium chamber which ensures the buoyancy of the turbine. To
increase the effectiveness, the blades will be rigid rather than flexible. The whole
"Coriolis" system will be 60 km long, oriented along the main direction of flow;
The width will be 30 km with 22 rows of turbines with 11 turbines in each row. It is will
be towed to an installation site and sunk to a depth of 30 m in order to not hinder
navigation.
The useful power of each turbine (when transferred to shore), with allowances made for
maintenance and service-loss costs, is expected to be about 43 MW, and this facility will
satisfy about 10% of the power needed by the state of Florida (USA).
The first experimental model of a similar turbine, 1.5 m in diameter, has already been
tested in the Florida Strait.
The project of the A turbine with a 12 m drive-wheel diameter producing 400 KW has also
been designed.
Transporting a water-wheel to an installation site
The salty water of the Oceans and seas conceals within itself huge reserves of energy, which can be effectively transformed into other forms of energy in regions with large salinity gradients near the mouths of the largest rivers of the world, such as the Amazon, Parana, Congo etc. The osmotic pressure rising where there is a mixing of fresh river waters with salty sea water, is proportional to the difference in the concentration of salts in these waters. The average pressure is about 24 atmospheres, but where the Jordan River flows into the Dead sea, the pressure is 500 atmospheres. It is thought that osmotic energy can be used where salt domes are located within the thickness of the Ocean bottom. The calculations have shown that by using energy created by the dissolution of salts on a petroleum salt dome, it is possible to realise the same amount of energy as is available from the petroleum on it.
Activities regarding the transformation of "salty" energy into electrical energy are still in the study and design phase, and the construction of prototypes for energy recovery from salts. Among the present offerings, versions of hydro-osmotic devices with semipermeable diaphragms have generated some interest. In these devices, suction of a solvent occurs, through a diaphragm in a solution. Fresh water, sea water and brine, the last obtained from the dissolution of salt-dome deposits, are used as solvents and solutions.
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1.Ocean water 2.Brine 3.Diaphragm 4.The osmotic chamber 5.Pumps 6.Cable 7.Salt dome 8.Turbine 9.Generator 10.The Ocean |
In the hydro-osmotic chamber, brine from a salt dome mixes with sea water. The water then passes through a semi-permeable diaphragm and under pressure goes into the turbine, which is connected to the electricity generator.
An underwater hydro-osmotic power station is placed at a depth greater than 100 m. Fresh water moves toward the water-wheel through a pipeline. After passing the turbine, it is evacuated into the sea by osmotic pumps containing semi permeable diaphragms. The remaining river water impurities and dissolved salts are deleted by the cleaning pump.
There is a huge quantity of energy contained within the biomass of seaweed located in the Ocean. It is thought that coastal seaweed can be processed and used for fuel. Phytoplankton have also considered for this process. The main ways of processing are considered to be fermentation of carbohydrates in seaweed into alcohols and fermentation of great amounts of seaweed without air for the production of methane. A design process has also been developed for processing phytoplankton for production of a liquid fuel. This engineering design is supposed to be combined with the use of oceanic thermal power stations, where waters heated at depth waters will provide a mechanism for phytoplankton cultivation using heat and nutrients.
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1.Containers 2.Pipelines 3.Pumps 4.Sump 5.Methane storage 6.Methane tank 7.Regenerator |
In the "Biosolar" project, there is an capability for continuous cultivation of the microseaweed, chlorella, in special containers floating on the surface of an open reservoir. The facility uses a system of floating containers connected by flexible hoses, and located on a coast or on a marine platform with the equipment for processing seaweed. The containers play the role of cultivators made from flat, cellular floats of reinforced polyethylene open to the air and sunlight from above. They are connected to a sump and regenerator by a hose. In the sump, part of the products of biosynthesis are removed, and from the regenerator in containers, the nutrient residues from anaerobic processing produce methane which is stored in a tank. The biogas obtained from the process contains methane and carbon dioxide.
