Energy in our life 1. Forms of energy:• Mechanical energy• Nuclear energy• Electric energy• Chemical energy• Thermal energy

2. Consumption in the world;3. Consumption in Italy;4. Consumption in Sicily;5. Renawable energy in Sicily:• Solar energy;• Wind energy;• Hydroelettric energy;

6. Why to save energy?

Mechanical energy

In mecanics, there are two types of energy:

• Kinetic energy: is what must be done on a body,initially stationary, to bring it into movement

• Potential energy: The potential energy of a body,usually denoted by U, is the ability to do work that the body possesses by virtue of his position within a field of conservative forces.

Nuclear energy

• Nuclear energy includes all sorts of phenomena which have energy production due to changes in atomic nuclei. The nuclear energy, along with renewable and fossil sources, is a primary energy source, that is present in nature and not derived from the processing of other forms of energy.

Nuclear, positive or not?

Benefits …• A nuclear power plant does not radiate CO2.• Nuclear power plants do not produce carbon dioxide, nitrogen and

sulfur, the main causes of the greenhouse effect.• Economic advantage: production of a nuclear energy reduces the

amount of oil and the dependence of economies on oil. All this leads to increased stability of the national and global economic sectors.

Disadvantages …

• Consequences of incidents:. The radiation to which the population is exposed, causes risk of

death from leukemia and cancer. Nuclear localization: The process of locating a nuclear plant and the storage of waste

is very difficult. Few nations are willing to sacrifice their land to host the nuclear waste.

Electric energy

• Electricity is a form of energy due to forces and fields of electrical origin, or which involves the movement of electric charges

Power plant:• A power plant is an industrial plant suitable for producing

electricity. Modern society is based in an essential use of electricity, so the production of energy and, consequently, power plants have a fundamental technological importance. The power plants produce energy almost exclusively in today's alternating current, using electric machines called alternators.

Chemical energy

• Chemical energy is energy that varies due to the formation or breaking of chemical bonds of any

kind. • It is deposited in the connections

between atoms within the molecule.

When these connections are broken (eg when a substance burns), a part of this energy lives released as heat and light.

Thermal energy• Thermal energy is a form of energy possessed by any body that has

a temperature above absolute zero. Thermal energy can be produced in large quantities simply through combustion, or by means of nuclear reactions, or by passing electric current through a wire with low resistance, as in electric stoves and all appliances that produce heat. The heat sources are the sun and the subsoil.

Geothermal energy

• Geothermal energy is energy generated by geologic sources of heat and can be considered a form of renewable energy.

• Geothermal energy is a form of usable energy that comes from the heat present in the deeper layers of the earth's crust. Penetrating deep into the earth's surface, the temperature gradually becomes higher, increasing by an average of about 30°

C per km in the crust.

Energy consuption in the world• About 1.6 billion people, a quarter of the world's population, are without

electricity.• Most of this population lives in developing countries such as Africa and

Asia.. • about 2.6 billion people use traditional biomass almost exclusively as a

primary source of energy

Mondo

38%carbone

1%rinnovabili13%gas

11%petrolio

19%idro-geo18%nucleare 3,7

1,5

1,5

4,2

2,8

2

4,4

3,6

2,5

4,5

4,2

2,7

0

2

4

6

8

10

12

mili

ardi

di t

ep

Richiesta energetica

1996

1998 2000 2002

Energy consumption in Italy:

0

5

10

15

20

25

30

35

40

45

50

2008 2009

Renewable

Coal

Natural gas

Nuclear

Other sources

Renewable energy in Sicily

0

10

20

30

40

50

60

2005

Hydroelectric

Thermoelectric

Wind

Fotovoltaic

• Energy needs in Sicily Net production in Sicily • 2003 : 20.571 GWh 2003: 24.387 GWh• 2004: 20.972 GWh 2004: 24.618 GWh• 2005: 21.406 GWh 2005: 24.796 GWh

Solar energy Solar energy can be used to generate electricity or

heat. The main technologies for the transformation of solar

energy are: solar panels; photovoltaic panels; Solar power in Priolo:. Energy from burning mirrors. First system in the world that

functions at night. Satisfies about 4 000 families. The structure has a feature that makes it unique: it is able to collect solar energy and preserve it for many hours, its 5,5 km long, special tubes run through 30 000 square feet of parabolic mirrors; it is able to generate electricity at night or in overcast skies.

Wind energy• Benefits of wind energy;• The wind is a renewable resource;• Does not emit pollutants;• Contributes to greenhouse gas reduction ;

Hydroelectric energy• Hydroelectric power is derived from

rivers and lakes, through the establishment of dams and penstocks. There are various types of dams: a center jump will take advantage of water falling from great heights available in mountainous regions. In-river plants are used river water masses that jump over small steps; to do this, however, the river must have a consistent flow.      The water of a lake or reservoir is piped downstream transforming its potential energy into kinetic energy due to distributors and the turbines. The kinetic energy is then transformed through the electric generator into electricity.

Why save energy…• To reduce environmental stressors: Energy saving is the

fastest and most efficient instrument in terms of cost, to reduce greenhouse gas emissions, thus improving air

quality. • For reasons of international politics: to meet the

agreements of the Copenhagen conference, which has set the target of lowering the average temperatures to 1.5 degrees by 2015.

• For economic reasons: The EU could save at least 20% of its current energy consumption.

• Economic growth in developing countries.