Bianca Rockenback
Hour 8
How Tidal Energy Works
 Tidal energy is energy obtained from changing sea levels. This
renewable energy source has great potential as tides are a lot
more predictable than wind power and solar energy which are
not at all consistent. There are three ways to harness tidal power
which are..
 Tidal Turbines-Which are used in similar technology to wind
turbines, although their blades are shorter and stronger. A way to
think of them is as underwater windmills. Basically the water
currents turn the turbines, which in turn activate a generator
that produces electricity.
 Tidal Lagoons-Tidal Lagoons are similar to barrages but have a
much lower cost and impact on the environment. They are selfcontained structures cut off from the rest of the sea.
Is Tidal Power Renewable?
 Yes, tidal power is renewable. The tides will continue
to flow, driven by gravitational forces. The energy of
the tides will not go away if we use their power to
generate electricity. It is renewable in the sense that we
cannot take away the source of the energy by using
them (unlike fossil fuels, of which there is a limited
supply)
http://wiki.answers.com/Q/Is_tidal_energy_a_renewa
ble_resource
Cost to Build
 The cost of setting up a tidal power station can be very
high, although once in place the operating costs are
low. As an example of the cost of setting up, a proposed
8000 MW tidal power plant and barrage system on the
Severn Estuary in the UK has been estimated to cost
US$15 billion, while another in the San Bernadino
strait which would produce 2,200 MW as a tidal fence
in the Philippines will cost an estimated US$3 billion.
(Source:Australian Institute of Energy)
Positive Aspects
 Tidal energy is renewable.
 The energy produced is clean and non-polluting.
 There is no carbon dioxide or any other by-products released. It
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produces no greenhouse gases or other waste.
It is a renewable energy that will help reduce our reliance on the
burning of fossil fuels.
There are two tides every day and they can be relied on. The
energy is there for the taking.
So the electricity supply is constant and efficient.
Once you've built it, the energy is free because it comes from the
ocean's power
It needs no fuel.
http://wiki.answers.com/Q/What_are_the_advantages_and_dis
advantages_of_renewable_tidal_power_as_an_energy_source
Negative Aspects
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Holding back the tide allows silt to build up on the river bed.
The dams and barrages sometimes interfere with shipping.
You will need to find a way to connect the electricity to the grid.
Pose same threats as large dams, altering the flow of saltwater in and out of
estuaries, which changes the hydrology and salinity and possibly negatively
affects the marine mammals that use the estuaries as their habitat
 Turbidity decreases as a result of smaller volume of water being exchanged
between the basin and the sea.
 The average salinity inside the basin decreases, also affecting the ecosystem
 A barrage across an estuary is very expensive to build, and affects a very wide
area - the environment is changed for many miles upstream and downstream.
Many birds rely on the tide uncovering the mud flats so that they can feed.
http://wiki.answers.com/Q/What_are_the_advantages_and_disadvantages_of_re
newable_tidal_power_as_an_energy_source
Tidal Energy’s Impact on the
Environment
 Some of the non-monetary costs associated with
barrage systems include destruction of habitat,
interruption of organisms’ travel routes, potential
electromagnetic, and potential acoustic pollution. In
addition, hydroelectric systems are well-known for
killing fish, and the waste heat that ends up in the
water reduces its capacity to store dissolved oxygen,
harming not only fish, but all organisms in the
affected area. Despite all this, such systems are
attractive to many because of their reliance on existing
technology and knowledge.
Countries using the most Tidal
Energy
 America Canada Brazil & Russia are big countries uses
more energy.
Tidal Energy Facts!!!!
 Tidal energy is the utilization of the sun and moon's
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gravitational forces - as the tide is the result of their influences.
Tidal energy is a type of energy that produces electricity and
other forms of power through the use of water.
Tidal energy is energy that could be obtained from the changing
sea levels. In other words, tidal energy is a direct result of tide
shifting from low to high.
The altering of the ecosystem at the bay is the biggest drawback
of tidal power. Damages like reduced flushing, winter icing and
erosion can change the vegetation of the area and disrupt the
balance.
Stream tidal energy is harnessed from currents – horizontal
water movement which is created by the rise and fall of tides.
Turbines, similar to wind turbines, can be anchored to the sea
bed to generate electricity from tidal currents.
Works Cited
 http://interestingenergyfacts.blogspot.com/2008/04/tidal-power-tidal-energyfacts.html
 http://oilprice.com/Alternative-Energy/Tidal-Energy/How-Does-TidalEnergy-Work.html
 http://www.darvill.clara.net/altenerg/tidal.htm
 http://renewableenergydev.com/tidal-energy/
 http://www.oceanenergycouncil.com/index.php/Tidal-Energy/Tidal-
Energy.html
 http://wiki.answers.com/Q/What_are_the_advantages_and_disadvantages_of
_renewable_tidal_power_as_an_energy_source