Renewable energy sources include solar, wind, ocean thermal, geothermal, and biomass. They are clean sources that do not emit harmful greenhouse gases. Solar energy can be harvested through various technologies, though some have intermittency issues. Wind energy is harvested via wind turbines and has the advantages of being clean, renewable, and using a free raw material. Geothermal energy harnesses heat from the Earth's crust to power turbines. Biomass energy is obtained by combusting or processing various organic waste materials and plant crops.

3. Why to use renewable energy sources?
The term renewable energy means the
energy produced from renewable
sources arising from particular natural
resources. They are therefore forms of
alternative energy to traditional fossil
fuels (which are part of non-
renewable) and many of them have
the distinction of being too clean
energy that not discharge harmful
and / or greenhouse gases such as
CO2, into air. They are thus the basis
for the so-called green economy.

4. From the energy point of view solar energy is alternative to
traditional fossil fuels, it is renewable and clean (green
energy) as well as one of the strengths in support of so-called
green economy in modern society. Solar energy can be
properly exploited through different technologies and
different purposes although in several of its technologies of
exploitation suffers from variability and intermittency of
production or not full programmability due to day-night
cycles and the cloud cover.

5. The wind is exploited for the
production of electrical energy using
devices with blades, used in so-
called Wind Farm "wind farms" to
obtain large quantities of electrical
energy. Three elements play, in
particular, in favor of this type of
energy: it is absolutely clean from
the ecological point of view, it is
renewable, and the raw material is
at zero cost. This source is
inexhaustible, free and produces no
waste. The disadvantage is the
large size of the installations.

6. A power plant for the conversion of the thermal energy of
oceans produces energy by exploiting the difference in
temperature between the different layers of ocean. The solar
energy absorbed by the surface of the sea heats it, creating a
temperature difference between the surface water, which can
reach 25 - 28 degrees, and those located for example at a depth
of 600 m, which do not exceed 6-7 degrees. The areas from
yellow to red in the image below are suitable for the
exploitation of the thermal gradient to produce electricity, the
potential of this technology is considerable in the appropriate
areas.

7. Geothermal energy is an important resource, not yet fully
exploited, to obtain an efficient mix of sources towards
sustainable development. This form of renewable energy
derive from the heat present in the deeper layers of the
Earth's crust.
The exploitation of geothermal energy is to pipe the steam
coming from the water sources of the underground routing
to turbines used for the production of electricity. The water
vapor is then reused for heating, the greenhouse
cultivation and spas.

8. A biomass power plant is a power plant that uses renewable energy
obtainable from biomass pulling through different techniques: by
direct combustion of biomass, by pyrolysi, by gasification. The term
biomass defines any organic matter such as waste industry residues
of agricultural processing and forestry, firewood, food industry
waste, dung and animal wastes, vegetable oils, waste but also plant
species cultivated for the purpose, such as poplar, miscanthus, or
other essences and fast-growing species and easy to grow, suitable
for the purpose.

9. Ppt created by students in the 3A class
I.C. "A. D'Aosta" - Ottaviano (NA) - ITALY

10. Ppt created by students in the 3A class
I.C. "A. D'Aosta" - Ottaviano (NA) - ITALY