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4th “Newsletter” – abril 2014 – Portugal
Theme: “Alternative energy sources/renewable energy”
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Natural resources
We call natural resources to all elements that
are in the Nature, used by man to improve his
life. The sun, wind and water are some of these
resources.
Renewables
We call renewable energy to all energy
sources that do not deplete.
Renewable energy is virtually inexhaustible,
but limited in terms of the amount of energy that
can be extracted at any time.
Renewable energy sources are characterized
by their capacity to regenerate and, as such, are
virtually inexhaustible and still respecting the
environment.
Both properties are its main difference with
respect to traditional energy sources.
Solar energy, wind energy, hydropower,
geothermal energy, wave energy, tidal and
biomass are renewable energy.
Solar energy
It is used to produce heat through solar
panels, or to produce electricity through
photovoltaic panels. During its construction, the
Solar Photovoltaic of Amareleja (Portugal), in
2008, was the largest in the world.
Photovoltaic of Amareleja
To capture solar photovoltaic panels (panels
with small light sensitive cells) are required.
When the sun's rays reach these cells, it produces
a reaction called photoelectric effect. It generates
electric current that can be consumed at the
moment or stored in batteries.
Wind energy
The wind turbines or wind generators are
used to produce electricity using the wind force.
“Caramulo” Wind Farm
The wind turbine comprises a tower, in its top
blades and a box called "nacelle" are installed.
The wind moves the blades of the turbine. Inside
the "nacelle" there are gears that increase the
speed produced by the blades and a generator
that transforms this motion into electricity.
Hydropower
It uses the power of water to produce electricity.
But for this to be possible, it is necessary to build
a dam.

2. Hydroelectric dam of Castelo de Bode
In a hydropower plant is the strength of the
accumulated water in the dam which drives a
turbine connected to a generator. From its
rotation results the production of electricity.
Geothermal energy
Inside Earth Planet exists much heat. But in
some locations this heat is closer to the surface
and can be harnessed to produce electricity. It's
what happens in this geothermal power station
located in the Azores Island (Atlantic Ocean)
Geothermal Central of Pico Vermelho - São Miguel Azores
Here was installed a pipe through which the
water runs and becomes steam due to the
temperature. It is the steam which drives the
turbine which is connected to a generator, which
transforms this movement into electricity.
Wave energy and tidal
Harnessing the energy released by the
movement of waves and tides. These movements
drive a turbine connected to a generator,
producing electricity.
WaveRoller in baleal - Peniche
Biomass
Biomass uses urban, forest and agricultural
residues. There are several types of biomass:
• With timber we build fires and produce heat.
• With vegetable and animal oils we can produce
biodiesel.
• Using organic matter can produce biogas, as
this plant.
It can still be transformed into biofuel, called for
biodiesel.
Unit Energy Use of Windward in Portimão (south Portugal)
The biomass is transformed into gas by
chemical processes, which can be used in
engines, for heating and electricity production.
Did you know that ...
Energy from the sun takes 8.5 minutes to reach Earth?
The sun's energy can be used to heat water?
In the Azores Islands people use up energy from inside the earth to make the stew from Furnas?
In the Tagus river tide mills still exist in activity that harnesses the energy of the ocean?
In Portugal almost half of the electricity comes from hydropower?
Work made by students of class 5th A