1. ENERGY AND ITS SOURCES
RENEWABLE SOURCES

2. RENEWABLE SOURCES
 Renewable energy is energy which comes
from natural resources such
as sunlight, wind, rain, tides, and geothermal
heat, which are renewable (naturally
replenished). About 16% of global final energy
consumption comes from renewables, with 10%
coming from traditional biomass, which is mainly
used for heating, and 3.4% from hydroelectricity.

3. NUCLEAR POWER
 As of December 2009, the world had 436 reactors.
Since commercial nuclear energy began in the mid
1950s, 2008 was the first year that no new nuclear
power plant was connected to the grid, although two
were connected in 2009. Annual generation of
nuclear power has been on a slight downward trend
since 2007, decreasing 1.8% in 2009 to 2558 TWh
with nuclear power meeting 13–14% of the world's
electricity demand.

4. HYDROPOWER
 Hydropower, hydraulic power, hydrokinetic
power or water power is power that is derived from
the force or energy of falling water, which may be
harnessed for useful purposes. Since ancient times,
hydropower has been used for irrigation and the
operation of various mechanical devices, such
as watermills, sawmills, textile mills, dock cranes, and
domestic lifts. Since the early 20th century, the term is
used almost exclusively in conjunction with the
modern development of hydro-electric power, the
energy of which could be transmitted considerable
distance between where it was created to where it
was consumed.

5. WIND POWER
 Wind power is the conversion of wind energy into
a useful form of energy, such as using wind
turbines to make electricity, windmills for
mechanical power, windpumps for water
pumping or drainage, or sails to propel ships.
 At the end of 2010, worldwide nameplate
capacity of wind-powered generators was
197 gigawatts (GW). Wind power now has the
capacity to generate 430 TWh annually, which is
about 2.5% of worldwide electricity usage.

6. SOLAR POWER
 Solar energy, radiant light and heat from the sun,
has been harnessed by humans since ancient
times using a range of ever-evolving technologies.
Solar radiation, along with secondary solar-
powered resources such as wind and wave
power, hydroelectricity and biomass, account for
most of the available renewable energy on earth.
Only a minuscule fraction of the available solar
energy is used.

7. GEOTHERMAL POWER
 Geothermal electricity is electricity
generated from geothermal energy. Technologies in use
include dry steam power plants, flash steam power
plants and binary cycle power plants. Geothermal
electricity generation is currently used in 24
countries, while geothermal heating is in use in 70
countries.
 Estimates of the electricity generating potential of
geothermal energy vary from 35 to 2,000 GW. Current
worldwide installed capacity is
10,715 megawatts (MW), with the largest capacity in
the United States (3,086
MW), Philippines, and Indonesia.

8. BIOMASS
 Biomass, as a renewable energy source, is biological
material from living, or recently living organisms. As an
energy source, biomass can either be used directly, or
converted into other energy products such as biofuel.
 In the first sense, biomass is plant matter used to
generate electricity with steam turbines & gasifiers or
produce heat, usually by direct combustion. Examples
include forest residues (such as dead trees, branches
and tree stumps), yard clippings, wood chips and
even municipal solid waste.

9. BIOFUEL
 Biofuel is a type of fuel whose energy is derived
from biological carbon fixation. Biofuels include
fuels derived from biomass conversion, as well
as solid biomass, liquid fuels and
various biogases. Although fossil fuels have their
origin in ancient carbon fixation, they are not
considered biofuels by the generally accepted
definition because they contain carbon that has
been "out" of the carbon cycle for a very long
time.