BIOMASS
Biomass is renewable organic material that comes from plants and animals. Biomass contains
stored chemical energy from the sun that is produced by plants through photosynthesis. Biomass
can be burned directly for heat or converted to liquid and gaseous fuels through various
processes.
Working of Direct Combustion
Direct Combustion systems feed a biomass feedstock into a combustor or furnace, where the
biomass is burned with excess air to heat water in a boiler to create steam. Steam from the boiler
is then expanded through a steam turbine converting heat energy into mechanical energy, which
runs a generator and produces electricity.
FIG: DIRECT COMBUSTION
Ocean Thermal Energy Conversion (OTEC)
Ocean Thermal Energy Conversion (OTEC) is a renewable energy technology that harnesses
the temperature difference between the warm surface waters of the ocean and the cold depths to
produce electricity.
WORKING OF OPEN CYCLE OTEC
The open cycle OTEC system depicted in
Fig. Operates by drawing warm surface
water from ocean (the working fluid) of
about 25-35oC in the evaporator
maintained at a reduced pressure by a
vacuum pump. The lower pressure in the
chamber causes the warm ocean water to
boil which generates steam to drive a
turbine (converting heat (steam) energy into mechanical energy) connected to a
generator(converting mechanical energy into electrical energy) to produce electricity. Once the
steam passes through the turbine, it enters a condenser cooled by cold water pumped from deep
below the ocean's surface where it is condensed back into a liquid. The condensate, which is now
desalinated water, is then vented from the system either to the ocean or to an isolated storage
tank.
WORKING OF CLOSED CYCLE OTEC
In the closed cycle system shown in Fig. warm surface water is used to heat an evaporator
containing a working fluid with a low-boiling point, such as ammonia. The heat from the warm
surface water causes the working
fluid (ammonia) to boil and
evaporate. The expanding vapor
from the boiling working fluid
(ammonia) drives the turbine
(converting heat (steam) energy
into mechanical energy) which is
connected to a
generator(converting mechanical
energy into electrical energy) to
produce electricity. After passing
through the turbine, the vapor enters a condenser cooled by cold ocean water pumped from deep
below the surface where it is condensed back into a liquid and recirculated through the system.
TIDAL ENERGY
Tidal energy is a form of hydropower that converts the energy of the tides into electricity or
other useful forms of power. The tide is created by the gravitational effect of the sun and the
moon on the earth causing cyclical movements of the seas
Basic principle of tidal power plant
A dam is constructed in such a way
that a basin gets separated from the
sea and a difference in the water
level is obtained between the basin
and sea. The constructed basin is
filled during high tide and emptied
during low tide passing through
sluices and turbine respectively.
The Potential energy of the water
stored in the basin is used to drive the turbine which in turn generates electricity as it is directly
coupled to an alternator.
SOLAR ENERGY
What is Solar Energy?
Energy produced by the sun,it is a clean, renewable source of energy.Harnessed by solar
collection methods such as solar cells and converted into usable energy such as electricity
Working of Solar Energy
Sunlight hit the solar panel (photovoltaic/ PV
Module) and absorbed by semi-conducting
materials such as silicon. Electrons are knocked
loose from their atoms, which allow them to
flow through the material to produce electricity.
This process is called the photovoltaic (PV)
effect. An array of solar panels converts solar
energy into DC (direct current) electricity. The
DC electricity enters an inverter. The inverter
turns DC electricity into 120-volt AC
(alternating current).The AC power enters the
utility panel in the house. The electricity (load) is then distributed to appliances or lights in the
house. When more solar energy is generated it can be stored in a battery as DC electricity and
will continue to supply your home with electricity in the event of a power blackout or at night
time.
WIND ENERGY
Wind Energy: Wind energy is defined as the process of capturing kinetic energy from wind and
converting it into usable mechanical power or electricity.
Working of Wind Energy
The wind turbine works on the principle of conversion of kinetic energy of wind to mechanical
energy used to rotate the blades of a fan connected to an electric generator.
When the wind or air touches the blades (or) vanes of the windmill. The air pressure can be
uneven, higher on one side of the blade and lower on the other. Hence, uneven pressure causes
the blades to spin around the center of the turbine. The turbine does not operate at wind speeds
above 55 mph with the use of the controller. The rotor shaft of the turbine (ie., low speed and
high speed) is interlinked with the gearbox which converts the speed from 30 to 60 rpm into
1000 to 1800 rpm. As the gearbox consists of gears, to transmit mechanical energy. These
speeds are most suitable to the generator for the generation of electricity. When the rotor of the
turbine rotates it drives a generator through a setup gearbox causing the generator to produce
electrical energy.
MAIN PARTS OF
WIND ENERGY
1. Rotor blade
2. Gear box
3. Generators
4. Nacelle
5. Power cables
6. Transformer
7. Switch yard
8. consumer
GEOTHERMAL ENERGY
Geothermal Energy: It is the energy that is generated from the heat within the Earth. Hot rocks
in the earth's core emit heat which generates steam and pressure and thus comes out of the earth's
surface. This steam is used to run turbines and produce electricity.
Working Of Geothermal Power Plant
1. Hot water is pumped from deep
underground through a well under
high pressure.
2. When the water reaches the surface,
the pressure is dropped (low
pressure) which causes the water to
turn into steam.
3. The steam spins a turbine, which is
connected to a generator that
produces electricity.
4. The steam cools off in a cooling
tower and condenses back to water.
5. The cooled water is pumped back into the Earth to begin the process again.
