Alternative energy resorses

ALTERNATIVE SOURCES OF ENERGIES PRESENTED By

T.V.N.VASISTA

MOBILE:+91-7416941475 E-mail:[email protected]

LESSON OBJECTIVE

By the end of this lesson I will be able to offer an explanation for the need to use alternative sources of energy

Target 1 met?

“It is defined as ability or capacity to do work”

We use energy to do work and make all movements. Energy lights our cities, powers our vehicles, and runs machinery in factories. It warms and cools our homes, cooks our food, plays our music, and gives us pictures on television.

1. Renewable energy-Energy that comes from naturally sources such as Sun ,wind etc. which is inexhaustible or naturally replenished

2. Non renewable energy-Energy sources that can’t be reproduced ,generated or replenished. Once depleted there is no more for future use.

WHAT IS AN ALTERNATIVE SOURCE OF ENERGY?

An energy source that can be used instead of fossil fuels

It is usually a renewable source of energy that could be used should fossil fuels run out

WHY IS THERE A NEED FOR ALTERNATIVE SOURCES OF ENERGY?

The graph that you completed last time shows just how much we rely on fossil fuels

90 per cent of the worlds energy supply’s come from fossil fuels Fossil fuels are convenient and relatively cheap – a litre of petrol

in 1998 would have been 20p if there was no tax added!

How much longer can we depend on fossil fuels?

Because they are fossil fuels they DO have a life expectancy“Oil has 40 – 50 years left”In 1960 they said this too! – what has happened is that we have found new reserves of oil and new technology has made the oil we use last longer

Burning fossil fuels has increased atmospheric pollution.

Vehicle exhausts contribute to acid rain more so than power stations burning coal.

The carbon stored in fossil fuels is released as carbon dioxide when they are burnt – this leads to the green house effect and global warming

Don’t get this confused with the hole in the ozone layer – this was caused by CFC’s

Fig:pollution from factories to the environment,causes global warming,which is the one of the major problem facing by the world.

The Green House Effect

Coal has the longest life expectancy Environmentalists dislike the burning of this fossil

fuel the most as it gives off the most CO2 Unless cheap alternatives to burning coal are

found there is likely to be an increase in its use – especially from Asia which has a lot!

SO WHAT ARE THE ALTERNATIVE ENERGY SOURCES TO FOSSIL FUELS?

Once upon a time – nuclear power was seen as the answer. Huge amounts of power could be produced from a small amount of uranium

However, it was not well known that it produced radioactive waste

The waste is dangerous to health and life for hundreds of years

There is no secure place for storage. Public confidence has also been shattered by the

explosion at Chernobyl in 1986

OTHER HOPES?

Now that nuclear power is considered too risky hopes lie with things like sun, water, wind, waves and tides.

Fig:Nuclear disaster caused by power plant in JAPAN due to TSUNAMI in ’11,radiation evolved from various countries due to nuclear wastes.

• Produced by fission or fusion of atoms.• Fission- When the nucleus splits nuclear energy is

release in the form of heat. • Fusion- Energy is also release when atoms combine

at high speed.• Power is generated in nuclear reactor by fission.

Advantages: Lower carbon dioxide (and other greenhouse gases)

released into the atmosphere in power generation.

Low operating costs (relatively). Large power-generating capacity able to meet

industrial and city needs. Disadvantages: Non renewable energy,Expensive to mine, refine and

transport. High construction costs due to complex radiation

containment systems and procedures.

Waste are generated during extraction and generation.

Radiation risk are high.Waste lasts 200 – 500 thousand years.

Hydropower is power that is derived from the force or energy of moving water, which may be harnessed for useful purposes. Prior to the development of electric power, hydropower was used for irrigation, and operation of various machines, such as watermills, textile machines, sawmills, dock cranes, and domestic lifts.

Hydropower available = ρQHWhere ρ-density of water, g-acceleration due to gravity,Q-discharge of water, H-head

Advantages:Advantages:Hydropower is clean. It does not emit any of the waste gases that contribute to air pollution, acid rain, and global warming. No fuel is required. Hydropower is reliable. As long as there is water, there will be an energy source. Hydropower is extremely efficient

oDisadvantages:Disadvantages:oHydropower dams disrupt the natural flow of rivers. oA large area for reservoir construction.oBuilding a dam on a river has major implications for the biota found in the river system. 

o Solar energy is the energy derived from the sun through the form of solar radiation. 

o Solar energy is the energy force that sustains life on the earth for all plants, animals, and people. The earth receives this radiant energy from the sun in the form of electromagnetic waves, which the sun continually emits into space.

o This solar energy can be tapped directly as concentrating solar power(CSP) (solar thermal energy)and photovoltaic(PV) cells.

o Solar Cell: The PV cell is the component responsible for converting light to electricity. Some materials (e.g., silicon is the most common) produce a photovoltaic effect, where sunlight frees electrons striking the silicon material. The freed electrons cannot return to the positively charged sites (‘holes’) without flowing through an external circuit, thus generating current.

o Solar cells are designed to absorb as much light as possible and are interconnected in series and parallel electrical connections to produce desired voltages and currents.

o PV is best suited for remote site applications that have small to moderate power requirements, or small power consuming applications even where the grid is in existence.

Concentrating solar power Photovoltaic cells

• Solar cells are long lasting sources of energy which can be used almost anywhere.

• Solar cells are totally silent and non-polluting.• Solar cells provide cost effective solutions to

energy issues in places where there is no mains electricity.

• As they have no moving parts, they require little or no maintenance at all, and have a long lifetime.

•The initial cost is quite high.•Most types of solar cells require large areas of land to achieve average efficiency.•Air pollution and weather can also have a large effect on the efficiency of the cells.•The silicon used in cells is also very expensive.

WIND ENERGY

Differential heating of the earth’s surface and atmosphere induces vertical and horizontal air currents that are affected by the earth’s rotation and contours of the land and generates wind.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. The total amount of economically extractable power available from the wind is considerably more than present human power use from all sources. Presently, India is ranked 4th in the world in terms of wind installed capacity.

• Wind mills or turbines works on the principle of converting kinetic energy of the wind in to mechanical energy.

• Power available from wind mill= ½ ρ A V³

Where, ρ – air density = 1.225 Kg. / m³ at sea level.(changes by 10-15% due to temperature and pressure variations)

A – area swept by windmill rotor = Π D²/4 sq.-m. (D – diameter )

V – wind speed m/sec.

• A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades.

• The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed.

SMALL(<10SMALL(<10kW)kW)Used in Used in HomesHomesFarmsFarmsRemote Remote ApplicationApplication

INTERMEDIAINTERMEDIATETE(10-250 kW)(10-250 kW)Used inUsed inVillage PowerVillage PowerHybrid Hybrid SystemsSystems

LARGELARGE(660k(660kW-2+ MW)W-2+ MW)

Used inUsed inCentral Central Station Wind Station Wind FarmsFarmsDistributed Distributed PowerPower

Advantages:Advantages:

Does not consume any fuel,Causes no air pollution.It is ecofriendly,The wind blows day and night, which allows windmills to produce electricity throughout the day.The energy consumed to manufacture and transport the materials used to build a wind power plant can be produced by the plant within a few months.DisadvantagDisadvantageses A wind farm may cover a large area of land, although many land uses such as agriculture are compatible.It can be used only in areas where there is sufficient wind speed available throughout the day.Power output is low as compared to other alternative sources like hydropower & nuclear

TIDAL ENERGY:TIDAL ENERGY:

• During high tide, water flows from sea to bay.• Turbine produces power.• During low tide, water flows from bay to sea.• Another set of turbine produces power.• Common turbines can also be used.•Power generated similar to hydropower.

oUtilization of organic waste to produce energyo Chemical energy stored in plants and animals or in the animal waste is called bio-energyoBurning of the biomass will release the energy in the form of heatoCan also be converted into other energy source such as bio-fuel

o On the contrary, biomass crops are seen as occupying agricultural land.

o Could contribute to global warming and particulate pollution if directly

burned

Advantages:Theoretically inexhaustible fuel source.

The use of waste materials reduce landfill disposal and makes more space for everything else.

Natural heat extracted from the earth's crust.

For electricity, steam is formed using the heat which rotates the turbine fitted to generator and at last, electricity is generated.

Geothermal energy generally involves low running costs since it saves 80% costs over fossil fuels and no fuel is used to generate the power

Being the renewable source of energy , geothermal energy has helped in reducing global warming and pollution.

To get geothermal energy, requires installation of power plants, to get steam from deep within the earth and this require huge one time investment.electricity towers, stations need to set up to move the power from geothermal plant to consumer.It is only suitable for regions where temperature below the earth are quite high and can produce steam over a long period of time.

ADVANTAGES OF USING NATURAL SOURCES OF ENERGY

They are inexhaustible – they will always be available – they are renewable

They are clean and will not damage the Earth There are several types – so one or more of

them is present in each country Most natural sources can be used on a small

scale and serve local needs therefore cutting costs of transmitting the energy

REVIEW

Explain why fossil fuels are: (a) cheap (b) in limited supply (c) dirty

PUT FORWARD ARGUMENTS IN FAVOUR OF:

(a) Using natural gas instead of coal (b) using nuclear power rather than oil (c) using alternative sources of energy rather

than nuclear power

MY DREAM:

I Just want to accomplish NUCLEAR ENERGY on running of satellites.