Presentation on the topic "Ebbs and flows, their use." Alternative energy: Tides Presentation on the topic of tidal energy

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Plan

Causes of tides Tidal friction Energy conversion during tides Use of TES Environmental issues Problems

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Causes of ebbs and flows

The highest tides are observed on the days of syzygies (new moons and full moons), the smallest (quadrature) coincide with the first and last quarters of the Moon. Between syzygies and quadratures, tide amplitudes can change by 2.7

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times. Due to changes in the distance between the Earth and the Moon, the tidal force of the Moon can change by 40% over the course of a month; the change in the tidal force of the Sun over a year is only 10%. Lunar tides are 2.17 times stronger than solar tides. Under the influence of the attraction of the Moon and the Sun, periodic rises and falls of the surface of the seas and

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oceans - ebbs and flows. At the same time, water particles perform both vertical and horizontal movements. In the same place there are two high tides per day, and between them there are two low tides. Tides are caused not only by the Moon, but also by the Sun through its gravity. However, due to the fact that the Sun is much further from the Earth than the Moon, its tidal effect is weaker.

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Tidal friction

Since the rotation of the Earth around its axis is ahead in time of the movement of the Moon around the Earth, tidal friction forces arise in the water shell of our planet, to overcome which rotational energy is spent, and the rotation of the Earth slows down (by about 0.001 sec per 100 years). According to the laws of celestial mechanics, a further slowdown in the rotation of the Earth will entail a decrease in the speed of the Moon’s orbit and an increase in the distance between the Earth and the Moon.

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Ultimately, the rotation of the Moon was slowed down for a long time due to the tidal friction that arose in it under the influence of gravity (tidal phenomena can occur not only in the liquid, but also in the solid shell of a celestial body). As a result, the Moon has lost its rotation around its axis and is now facing the Earth with one side

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Conversion of energy during ebb and flow of tides

The periodic rise and fall of ocean water levels can be used as a renewable energy source. In many places off the coasts of Nova Scotia, Alaska and northern France, tides reach heights of 12 meters or more twice a day. Since the tidal currents in these places find themselves in narrow channels, there is a possibility of converting their energy into electricity.

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Use of PES

Nowadays, tidal energy is mainly converted into electrical energy at tidal power plants and is then added to the general flow of energy produced by power plants of all types. Unlike river hydropower, the average tidal energy varies little from season to season, allowing tidal

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power plants more uniformly provide energy to industrial enterprises. Tidal power plants use the difference in water levels created during high and low tides. To do this, the coastal basin is separated by a low dam, which retains tidal water at low tide. Then the water is released and it rotates the hydraulic turbines. Tidal power plants are valuable

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energy support of a local nature, but there are not many suitable places on Earth for their construction so that they can change the overall energy situation. The cost of energy at PPP is the lowest in the power system compared to the cost of energy at all other types of power plants

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Environmental issues

Environmental characteristics tidal power plants Environmental safety: . PES dams are biologically permeable. the passage of fish through the PES occurs almost unhindered. The main food supply of the fish stock is plankton: 5-10% of plankton die at the PPP, and 83-99% at the HPP. the decrease in water salinity in the TES basin, which determines the ecological state of marine fauna and ice, is 0.05-0.07%.

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TPPs do not have a harmful effect on humans: there are no harmful emissions (unlike thermal power plants), there is no flooding of land and the danger of a wave breaking into the downstream (unlike hydroelectric power plants), there is no radiation hazard (unlike nuclear power plants), the influence of catastrophic natural and social phenomena on the TPPs (earthquakes, floods, military actions) do not threaten the population in areas adjacent to the PES.

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Problems

The main obstacles to the widespread development of tidal energy in the world are the design of the turbine and the cost of constructing a tidal power plant. Turbines designed to operate in two directions (ebb and flow) turned out to be technically complex and extremely expensive to manufacture. The process of constructing a power station - on the water, far from the shores - also turned out to be very expensive. Not everywhere there are original ones natural conditions for the construction of a power station, there are not yet those necessary for establishing profitable production electricity technology. Many projects are still under development.

Types of energy resources of the World Ocean

Wave energy
Thermal
energy
Energy
tides and
low tides
Wind energy
Energy
currents

Wave energy

The work of wave energy
stations - the impact of waves on workers
organs, in the form of:
floats
pendulums
Blades
shells
Mechanical energy of their movements
using electric generators
converted to electric.

Thermal energy

Feasibility
use of thermal
energy starts with
temperature difference of 20
degrees
Are environmentally friendly
clean mining method
energy, but require
large material
costs

Wind energy

The most common type
clean energy
Ocean wind farms produce
more energy because over the seas
and the oceans blow more powerful
wind
Leading country in wind energy
– Denmark, about 2500 wind
installations, power 200 mW

Energy of currents

The least developed type of energy.
Prospects are not the same for
energy production - Gulf Stream,
Kuroshio, Florida, as well as
currents of the straits: Gibraltar,
English Channel, Kuril
Modern equipment
extracts energy from the flow in
1m/s

Energy of ebbs and flows

Twice a day at the same time
time sea level then
rises, then falls.
These are gravitational forces
The moon and sun are attracted to
itself masses of water.
Offshore fluctuations
water level does not exceed 1
m, but they are right next to the shore
can reach 13 m
The most striking example is
Penzhinskaya Bay on Okhotsk
sea.

Energy of ebbs and flows

The most important type of energy resource for the world's oceans, it is also the oldest
way. People used it back in the 16th century! One of the advantages of tidal energy
is its constancy

Tidal power plants

The principle of operation of tidal
power plants
Is being built at the mouth of a river or bay
a dam, in the body of which
hydraulic units are installed.
Behind the dam is created
tidal pool, which
filled with tidal
current passing through
turbines.
At low tide the flow of water
rushes out of the pool into
sea, rotating turbines in
in the opposite direction.

Construction opportunities

It has been established that opportunities for
structures of large tidal
power plants are available in 25 - 30 places.
The largest tidal resources
Russia, France,
Canada, UK, Australia,
Argentina, USA.
This is due to the presence of coastal
areas where the tide reaches 1015 m or more.

Conclusion

Currently, energy resources are mostly classified as resources of the future,
since they are used on a small scale and only by the most developed,
less often developing countries
The main advantages are environmentally friendly use and inexhaustible resources
Cons – high costs for construction the necessary equipment, dependence of countries
depending on geographical location,

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Constantly experiencing energy hunger, humanity is turning more and more attention to alternative energy sources. And in this regard, the World Ocean is an inexhaustible storehouse of energy resources. One of the most powerful sources of ocean energy is tidal currents.

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For centuries, people have speculated about the cause of sea tides. Today we know for sure that the mighty natural phenomenon- rhythmic movement sea waters cause the gravitational forces of the Moon and the Sun.

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The highest and strongest tidal waves occur in small and narrow bays or estuaries of rivers that flow into seas and oceans. The tidal wave of the Indian Ocean rolls against the current of the Ganges at a distance of 250 km from its mouth. The tidal wave of the Atlantic Ocean extends 900 km up the Amazon. In closed seas, such as the Black or Mediterranean, small tidal waves with a height of 50-70 cm occur. Tidal waves

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This is a special type of hydroelectric power station that uses the energy of tides, and in fact the kinetic energy of the Earth's rotation. Tidal power plants are built on the shores of seas, where the gravitational forces of the Moon and the Sun change the water level twice a day. Fluctuations in water levels near the shore can reach 13 meters. Tidal power plants

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Alternative energy sources are currently doing an excellent job. Mainly in the form alternative energy use windy, as well as solar energy. There is also the energy of ebbs and flows, which is used quite rarely. Although, it is this alternative method of generating energy that does not create noise, vibration, and also does not affect nature in any way. To create such sources of energy generation using the ebb and flow of tides, the costs are significantly high. But with the help of unique turbines that convert the movement of water into energy, the price range of such a system can be more affordable.

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