renewable electric energy sources

8/6/2019 Renewable Electric Energy Sources

http://slidepdf.com/reader/full/renewable-electric-energy-sources 1/34



y PH-I --------INTRODUCTION

y ENERGY PROBLEM

y PRESENT CONDITION

y RENEWABLE ENERGY FOR SUSTAINABLE DEVELOPMENT

y TOWS ANALYSIS



y PH-II---------SOLAR ENERGY

y WIND ENERGY

y TIDAL ENERGY

y BIOMASS

y GEOTHERMAL ENERGY

y HYDRO-POWER

y PH-III--------CONCLUSION



y INDUSTRIES

y DOMESTIC LOAD



y ENERGY DEFICIT GLOBALLY

y POPULATION

y FASTER DEPLETION OF FOSSILS

y ENVIRONMENTAL EFFECTS

y DIFFICULTY IN INCLUDING RENEWABLEENERGY SOURCES IMMEDIATELY



y THREATS

y OPPORTUNITIES

y WEAKNESSES

y STRENGTHS



ySOLAR ENERGY



� Photovoltaic cells are solar cells that convert the sun¶s

energy into electricity.

� Solar cells have no moving parts, and they run on

nonpolluting power from the sun.

� However, they produce a very small electrical current.

Meeting the electricity needs of a small city would

require covering hundreds of acres with solar panels.



Photovoltaic

CellsSunlight falls on a

semiconductor,

causing it to release

electrons. The

electrons flow

through a circuit

that is complete

when another

semiconductor in

the solar cell

absorbs electronsand passes them on

to the first

semiconductor.



y Solar cells require extended periods of sunshine toproduce electricity. This energy is stored in batteries,

which supplies electricity when the sun is not shining.

y

Currently, solar cells provide energy for more than 1million households in developing countries, whereenergy consumption is minimal and electricity distribution networks are limited.



y Energy from the sun warms the Earths surfaceunevenly, which causes air masses to flow in theatmosphere.

y

We experience the movement of these air masses as wind.

y Wind power, which converts the movement of windinto electric energy, is the fastest growing energy

source in the world.



y Wind turbines are used to capture the energy from the wind.

y Large arrays of wind turbines are called w ind farms.

Large wind farms supply electricity to thousands of homes.

y In windy rural areas, small wind farms with 20 or fewerturbines are also becoming common.

y Because wind turbines take up little space, somefarmers can add wind turbines to their land and stilluse the land for other purposes.



y The cost of wind power has been steadily falling as wind turbines have become more efficient.



y Tidal power traditionally involves erecting a dam across the

opening to a tidal basin. The dam includes a sluice that isopened to allow the tide to flow into the basin; the sluice isthen closed, and as the sea level drops, traditionalhydropower technologies can be used to generateelectricity from the elevated water in the basin. Someresearchers are also trying to extract energy directly from

tidal f low streams.y The energy potential of tidal basins is large the largest

facility, the La Rance station in France, generates 240megawatts of power. Currently, France is the only country that successfully uses this power source. French engineers

have noted that if the use of tidal power on a global level was brought to high enough levels, the Earth would slow itsrotation by 24 hours every 2,000 years.

y Tidal energy systems can have environmental impacts ontidal basins because of reduced tidal f low and silt buildup.



y 1Wave Energy

y Kinetic energy (movement) exists in the moving waves of theocean. That energy can be used to power a turbine. In this the

wave rises into a chamber. The rising water forces the air out of the chamber. The moving air spins a turbine which can turn a

generator.y When the wave goes down, air flows through the turbine and

back into the chamber through doors that are normally closed.y This is only one type of wave-energy system. Others actually use

the up and down motion of the wave to power a piston thatmoves up and down inside a cylinder. That piston can also turn agenerator.

y Most wave-energy systems are very small. But, they can be usedto power a warning buoy or a small light house.



y Another form of ocean energy is called tidal energy. When tides comes into the shore, they can be trappedin reservoirs behind dams. Then when the tide drops,the water behind the dam can be let out just like in a

regular hydroelectric power plant.y In order for this to work well, you need large increases

in tides. An increase of at least 16 feet between low tideto high tide is needed. There are only a few places

where this tide change occurs around the earth. Somepower plants are already operating using this idea.One plant in France makes enough energy from tidesto power 240,000 homes.



y

The final ocean energy idea uses temperature differences inthe ocean. If you ever went swimming in the ocean anddove deep below the surface, you would have noticed thatthe water gets colder the deeper you go. It's warmer on thesurface because sunlight warms the water. But below the

surface, the ocean gets very cold. That's why scuba divers wear wet suits when they dive down deep. Their wet suitstrapped their body heat to keep them warm.

y Power plants can be built that use this difference intemperature to make energy. A difference of at least 38

degrees Fahrenheit is needed between the warmer surface water and the colder deep ocean water.

y Using this type of energy source is called Ocean ThermalEnergy Conversion or OTEC. It is being used in both Japanand in Hawaii in some demonstration projects



y Biomass fuel consists of plant material, manure, orany other organic matter that is used as an energy source.

y

Fossil fuels can be thought of as biomass energy sources, although they are nonrenewable.

y Renewable biomass fuels, such as wood and dung, aremajor sources of energy in developing countries.

y More than half of all wood cut in the world is used asfuel for heating and cooking.



SOLAR ENERGY PHOTOSYNTHESIS BIOMASS ENERGY



y In some areas, deposits of water in the Earths crust areheated by geothermal energy.

y Geothermal energy is the energy produced by heat

within the Earth.y The United States is the worlds largest producer of

geothermal energy.

y Although geothermal energy is considered a renewable

resource, the water that is used must be managedcarefully so that it is not depleted.



y Geothermal power plants generate electricity usingthe following steps Steam rises through a well

Steam drives turbines, which generate electricity Leftover liquid is pumped back into the hot rock

y The leftover liquid, water, is returned to Earths crustbecause it can be reheated by geothermal energy and

used again.



y More than 600,000 homes inthe United States are heatedand cooled using geothermalheat pumps.

y

A geothermal heat pumpuses stable undergroundtemperatures to warm andcool homes because thetemperature of the ground isnearly constant year-round.

y A heat pump is simply a loopof piping that circulates afluid underground.



y H ydroelectric energy is electrical energy producedby falling water.

y Hydroelectric energy accounts for 20% of the worlds

electricity.y Large hydroelectric power plants have a dam that is

built across a river to hold back a reservoir of water.

y The water in the reservoir is released to turn a turbine,

which generates electricity.



y Hydroelectric dams are expensive to build, butrelatively inexpensive to operate.

y Unlike fossil fuel plants, hydroelectric dams do not

release air pollutants that cause acid precipitation.y Hydroelectric dams also tend to last much longer than

fossil fuel-powered plants.

y Dams also provide other benefits such as flood control

and water for drinking, agriculture, industry, andrecreation.



y While in developing countries the construction of large dams continues, in the United States, the era of large dam construction is probably over.

y

One modern trend is micro-hydropo w

er, which iselectricity produced in a small stream without havingto build a big dam. The turbine may even float in the

water, not blocking the river at all.

y

Micro-hydropower is much cheaper than largehydroelectric dam projects, and it permits energy to begenerated from small streams in remote areas.



y CONCLUSION



?

ANY QUESTION

renewable electric energy sources

Documents