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Renewable energy
31.01.2016
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Mohammed Jaffar Yousif
Grade 10
Physics

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Definition
A renewable energy resource is one that will not run out
Types of Renewable energy
1. Hydroelectric Power
2. Tidal Power
3. Wave Energy
4. Wind Power
5. Solar Power
Hydroelectric Power
The turbine turns the generator rotor which then converts this
mechanical energy into another energy form -- electricity. Since
water is the initial source of energy, we call this ​hydroelectric
power​ or hydropower for short. At facilities called ​hydroelectric
power plants, hydropower is generated.

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Tidal Power
Tidal power​, also called ​tidal energy​, is a form of hydropower
that converts the ​energy​ obtained from ​tides​ into useful forms
of ​power​, mainly electricity. Although not yet widely used, ​tidal
power​ has potential for future electricity generation. ​Tides​ are
more predictable than wind ​energy​ and ​solar​ ​power​.

4. 3
Wave Energy
A ​wave​ farm – or ​wave​ power farm or ​wave energy​ park – is a
collection of machines in the same location and used for the
generation of ​wave​ power electricity. ​Wave​ farms can be either
offshore or nearshore, with the former the most promising for the
production of large quantities of electricity for the grid.
Wind Power
A ​wind turbine​ is a device that converts kinetic ​energy​ from the ​wind
into electrical ​power​. The term appears to have migrated from
parallel hydroelectric technology (rotary propeller). The technical
description for this type of machine is an aerofoil-powered generator.

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Solar Power
Solar power​ is the conversion of sunlight into ​electricity​, either
directly using photovoltaics (PV), or indirectly using concentrated ​solar
power​ (CSP). Concentrated ​solar power ​systems use lenses or
mirrors and tracking systems to focus a large area of sunlight into a
small beam.
Tidal Energy Generation
Energy can be harnessed from the tides in two ways: using the change
in height of the tides (potential); and using the flow of the water
(kinetic).
Tidal power is very sensitive to speed. The power output varies as the
cube of the speed. In other words, if the water flows twice as fast, it
makes eight times the power.
Also, tidal turbines do not have to spin as fast as windmills to generate
power, because water is roughly 800 times more dense than air.
Tidal power technology is constantly evolving. However, the most
common technology today can be classified into three main
categories:

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● In-Stream Devices​ make use of the kinetic energy of moving
water to power turbines, in a similar way as windmills use
moving air. This method is gaining in popularity because it’s
removable, it can be scaled up gradually (from one device, to an
array, to a larger farm), and has lower potential costs and
ecological impact (compared to barrages).
● Barrages ​make use of the potential energy in the difference in
height – or head – between high and low tides. They are
essentially dams across the full width of a tidal estuary – or the
mouth of a river that has a free-flowing connection to the
ocean. Barrages have very high costs, a worldwide shortage of
viable sites and associated environmental concerns.
● Tidal Lagoons​ are similar to barrages but can be constructed
as self-contained structures not extending fully across an
estuary. Some suggest this may reduce both costs and overall
impacts. They can be configured to generate continuously,
which is not the case with barrages.
The in-stream tidal turbines tested at FORCE use the flow of the water
as the source of power. Each of the turbines is designed to use the
flow of the passing water to turn an impeller, just like a windmill. Each
turbine is different in how it manages this but, in the end, each uses
the rotation of its turbine to turn an electrical generator.
Designed to operate in the open flow of water in the Minas Passage,
the turbines have to operate in a range of water speeds, from zero to
a maximum of 10 knots. As water speeds can vary from the surface to
the sea floor, test conditions for each turbine will differ slightly and

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depend on both the site location and the depth at which they are
positioned.