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Thursday, 10 May 2012

The Renewable Energy Guide

Introduction to Renewable energy
We all are answerable for climate change and it is our responsibility to work for its solution. In
the past century, it has been noticed that the consumption of non-renewable sources of energy
has caused more environmental damage than any other human activity. Electricity generated
from fossil fuels has led to high concentrations of injurious gases in the atmosphere.
In spite of the harmful effects, the price of the fuels is pushing relentlessly upwards. The reason
is that the demand is exceeding supply by a few million barrels a day and the gap is getting
The need of the hour is sustainable, clean and green energy. We can no longer afford to spew
out tones of carbon dioxide into the atmosphere, nor can we easily cope with the rising fuel
prices anymore. The myth of inexhaustible natural reserves has been dispelled. We’re
surrounded by many renewable sources of energy, merely waiting to be tapped into.
Renewable energy is the energy derived from natural processes that are replenished frequently.
Renewable sources can avoid above problems by using energy sources that either will last
longer than the human race or can be regenerated. Most renewable energy sources are
environmentally friendly, can fight global warming by reducing carbon emissions and also allow
the economies to lessen their dependencies on politically turbulent nations. Renewable energy
is the energy generated from solar, wind, rain, tides, hydropower, biomass, geothermal
resources, and bio fuels and hydrogen derived from renewable resources.
Different types of renewable energy
Renewable energy is derived from natural processes that are constantly renewed in a short
period of time. Renewable sources of energy differ widely in their cost-effectiveness and their
availability around the world. Though water, wind, and solar may appear free, but their cost
comes in assembling, harnessing, and transporting the energy that could be used. For instance,
to make use of energy from water, a dam with electric generators and transmission lines is
· Renewable energy sources used most often are:
· Solar
· Wind
· Geothermal
· Hydro power
· Biomass

Solar energy is the cleanest and inexhaustible of all known energy sources. Solar energy is the
light, heat and other radiation that is released from the sun. Solar radiation holds huge amounts
of energy and is responsible for almost all the natural processes on earth.
Science behind the Working of Solar light Panels:
Solar light Panels have photovoltaic cells or Solar Cells which are arranged in a grid-like pattern
on its surface. Solar cells are made of special materials for example silicon. When the solar
energy falls on Solar light Panels, this energy knocks electrons loose and allows them to flow
freely. The solar cells have the electric field that makes the loose electrons to move in certain
direction, which is a current. To take out this current off for external use we place metal
contacts on the top and bottom of our solar cell.
.Different components used to make solar power:
· Solar cells, which are commonly called PV panels
· One or more batteries
· Charge regulator for a stand-alone system
· Inverter, when alternating current (ac) rather than direct current (dc) is required
· Wiring
· Mounting hardware or a framework.

Wind is a form of solar energy. The irregular heating of the atmosphere by the sun, the
irregularities of the earth's surface, plus rotation of the earth causes winds. This wind energy,
when "harvested" by wind turbines produces energy which can be trapped to generate
electricity and carry out many functions.

Wind energy is generated by the process by which the wind is used to generate mechanical
power or electricity. When wind moves over the turbine blades, it generates a lift. The lift makes
the blades rotate and hence rotate the shaft. The rotating shaft moves a magnetic field in the
generator, which in turn creates electricity
 A Wind turbine includes the following parts:
· Gearbox – Gear box connects the low and high-speed shaft to each other
· Blades - wind blowing over the blades causes them to lift and rotate
· Hub - the sphere object used to mount the blades on
· Generator – Generator creates at least 60-cycle AC electricity
· Tower – Tower is the metal pole the turbine operates from. Tower is at least 100 feet
off the ground so that the turbine can capture the least turbulent wind
· Rotor hub – Rotor hub is the hub and the blades together
· Yaw drive – Yaw drive is required only for an upwind turbine; it keeps the rotor facing
the wind
· Yaw motor – It provides power for the yaw drive
· Nacelle – Nacelle sits on top of the tower and clings to the gear box
· Low-speed shaft – It is turned by the rotor at a rate of 30 to 60 rotations every minute
· High-speed shaft – It connects to the generator and drives it
· Anemometer –Anemometer is used to measures the speed of the wind.

Do you know that Earth’s center can reach 12000 degrees Fahrenheit? Just imagine if we could
tap that heat for our own use. Geothermal systems do just that. Geothermal energy is the
energy that is generated by heat stored beneath the Earth's surface. Geothermal energy taps
the Earth’s internal heat for lot of purposes including electric power production, heating and
cooling of buildings
Three geothermal technologies currently used in the United States are:
· Direct-use systems
· Geothermal power plants
· Geothermal heat pumps
Direct-use systems:
In these systems, a well is drilled into a geothermal reservoir to supply a steady stream of hot
water. The water is brought up from the well, and with the help of piping, a heat exchanger, and
controls the heat is delivered directly for its intended use. A disposal system in some cases
injects the cooled water underground or disposes of it in a surface storage pond. This
Geothermal hot water is used for many purposes including heating buildings, raising plants in
greenhouses, heating water for fish farms, drying crops, or for industrial process.
Geothermal power plants:
In these systems geothermal hot water or steam is used to generate electricity. Older types of
geothermal power plants uses steam from the deep wells to directly drive a turbine to produce
electricity. Nowadays Flash steam plants are the most common type of geothermal power
plants. They use very hot water which is pumped under high pressure to the generation
equipment at the surface. Water is vaporized and the vapor drives turbines to generate
Geothermal heat pumps:
Geothermal heat pumps rely on the fact that below the surface, the Earth remains at a relatively
constant temperature all through the year, warmer than the air over it in the winter and cooler
in the summer. This heat pump transfers heat stored in the ground into a building in winter and
it transfers the heat out of the building and back into the ground in summer. The geothermal
heat pump has series of pipes, buried in the ground close to a building to be conditioned. Fluid is
circulated all the way through the pipes to either absorb heat from the ground or distribute heat
to the ground. These Geothermal heat pumps are used for space heating and cooling in
addition to water heating, for residential and commercial applications.

4)Hydroelectric power
The hydroelectric power plants or Dams are used to generate electricity from water on large
scale basis. The hydroelectric power plant is built across the large river which has sufficient
quantity of water. In case the river is large, more than one dam can also be built across the river
but at different locations. Flowing water generates energy which can be captured and turned
into electricity. This is called hydro power or hydroelectric power.
Working or Principle behind Hydroelectric Power Plant:
The water that flows in the river possesses two type of energy: the kinetic energy which is due
to flow of water and potential energy which is due to the height of water.
In hydroelectric power plants potential energy of water is utilized to generate electricity
Water is made to fall with a high force. The force of the water being released through the dam
falls on the blades of turbine, which is turned by the moving water. The shaft from the turbine
goes into the generator, which generates the power. Power lines are linked to the generator
which carries electricity to the homes or factories. When ever the water is done going through
the turbine, the water go back to the river

The term Biomass often refers to organic material such as timber and crops grown particularly
to be burnt to generate heat and power. Biomass power is power acquired from the energy in
plants and plant-derived resources, such as food crops, grassy and woody plants, remains from
agriculture or forestry, and the organic constituent of municipal and industrial wastes. The highyielding
energy crops like trees and grasses, coupled with high-efficiency conversion
technologies, can supplement our use of fossil fuels and help us take action to global climate
change concerns. Agricultural crops and residues, industrial wood and logging residues, farm
animal wastes, and the organic portion of municipal waste all are biomass feedstock.
We need to make sustainable use of plants or trees as fuel, and replant them as we harvest
them. As long as biomass is produced sustainably by only using as much as is grown—the
battery will last forever. Biofuel technologies can competently transform the energy in biomass
into transportation, heating, and electricity generating fuels.