pmel energy source enviroment ghg 1

SUMBER ENERGI UNTUK

PEMBANGKIT LISTRIK

Permasalahan GHG (Gas Rumah

Kaca) serta Solusi dengan

ENERGI BARU TERBARUKAN

Dosen : Ir.SYARIFFUDDIN MAHMUDSYAH,M.Eng.

The Magic Of Electricityby Syariffuddin Mahmudsyah

Electricity: A form of energy associated

with a flow of electrons whose movements can

create fields of force and generate energy

Electricity is a form of energy. It is generated by millions of free-flowing electrons whose movements create force fields and generate energy from motion. When you do things like surf the Net, heat something in the microwave, watch TV, and turn on the light in your bedroom, you are using electricity.

If you want to understand electricity, you first need to know a little about matter, atoms, and electrons. Matter is anything that takes up space or has mass. Everything you can touch is made of matter. Atoms are the very small "building blocks" of matter. Everything you touch is matter and is made up of atoms (lots and lots of atoms!). These very small atoms are made up of an even smaller nucleus and one or more small electrons circling the nucleus. Electrons always have a negative ("-") electric charge, and it is this electric charge that is responsible for what we call electricity.

Did You Know? Electrons don't really race from one end of the wire to the other like sprinters at a track meet. In an electric current the electrons jump from one atom to another, pushing other electrons in front of them as they go. They really behave more like runners in a relay race, passing along the baton (electrical energy) from one atom to the next. The electrons don't actually travel very fast, but the electrical energy that they create travels at the speed of light! Remember that electrons carry a negative electrical charge. When electrons move from one place to another they take that negative charge with them. It is this movement of charge that we refer to as electricity! So if you can get a bunch of electrons to cooperate and all head in the same direction, you've got electricity!

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

ELECTRICITY AT WORK

If you walk across a carpet,

electrons move from the rug

to you. Now you have extra

electrons. Touch a door

knob and ZAP! The

electrons move from you to

the knob. You get a shock.

Static electricity is usually

caused when certain

materials are rubbed against

each other, like wool on

plastic or the soles of your

shoes on the carpet. The

process causes electrons to

be pulled from the surface of

one material and relocated

on the surface of the other

material. Rubbing a balloon

on a wool sweater creates

charges on the surfaces.

The same goes for a balloon

and a wall. The material that

loses electrons ends up with

an excess of positive (+)

charges. The material that

gains electrons ends up an

excess of negative (-)

charges on its surface.

STATIC ELECTRICITY

ELECTRICITY ON THE MOVE

In the diagram to the left there has to be a complete electric circuit to light this bulb. The electric current flows from one terminal of the battery through the wire to the other terminal. If we make a gap or a break in the circuit by using a switch, the electricity cannot flow through and the light goes out. Air is an insulator. When we flip the switch on, the two metal parts in the switch come together to close the gap and complete the electrical circuit.

In this electrical circuit

below the electrical

current flows from one

terminal through a

metallic plate that is

highly conductive, a

switch and a fuse to

complete the electrical

circuit. If there is a

break or gap in any of

these the circuit will not

be complete and the light

will not illuminate.

A fuse is a safety device that breaks the circuit if to much electricity is passing through it.

ELECTRICITY

KILLS

An electric shock can occur upon contact of a human or animal body with any source of voltage high enough to cause sufficient current flow through the muscles or nerves. The minimum detectable current in humans is thought to be about 1 mA. The current may cause tissue damage or heart fibrillation if it is sufficiently high. When (and only when) an electric shock is fatal, it is called electrocution.The average

lightning bolt carries about 30,000 amps of charge, has 100 million volts of electric potential, and is about 50,000

｡F.

SAFETYMicroshock is a direct current path to the heart tissue

Macroshock is current flowing across intact skin and through the body. Current traveling from arm to arm or between an arm and a foot is likely to traverse the heart and so is much more dangerous than current traveling between a leg and the ground.

Avoid contact of any

kind with power lines

either downed in a

storm or ones that are

leading into a home.

They may cause

serious injury or even

death by

electrocution.

Never overload electrical

outlets and circuits.

Overloaded electrical

outlets, or circuits that

supply power to several

outlets, is a major cause of

residential fires. Overloaded

outlets and circuits carry

too much electricity, which

generates heat in

undetectable amounts. The

heat causes wear on the

internal wiring system and

can ignite a fire.

The term "ground" refers to a

conductive body, usually the

earth. "Grounding" a tool or

electrical system means

intentionally creating a low-

resistance path to the earth.

When properly done, current

from a short or from lightning

follows this path, thus preventing

the buildup of voltages that

would otherwise result in

electrical shock, injury and even

death. When you create that path

to ground is when shock or

electrocution occurs.

Ground fault circuit interrupter

(GFCI) are good idea when

plugging devices such as a tv’s,

toaster, and or tools into walls.

FATHERS OF ELECTRICITY

Ben Franklin an American writer, publisher, scientist

and diplomat, who helped to draw up the US

Constitution also helped to discover the magic of

electricity. Franklin started working with electricity in

the 1740's and believed that lightning was a flow of

electricity taking place in nature. In 1752 Franklin

proved this theory that lightning was a form of

electrical energy by fastening a iron spike to a silken

kite, which he flew during a thunderstorm, while

holding the end of the kite string by an iron key.

When lightening flashed, a tiny spark jumped from the

key to his wrist. The experiment proved Franklin’s

theory, but was extremely dangerous- He could easily

have been killed.

ELECTRIC LIGHTWhen an electric current passes through a wire, the atoms not only produce heat when they resist the movement of electrons, they may also change some of the electrical energy into light. In 1878 Joseph Swan, a British scientist, invented the incandescent filament lamp and within twelve months Thomas Edison made a similar discovery in America. Light bulbs contain very thin wires, called filaments, which force the electrons to travel through an extremely small area. The resistance is further increased by making the wire very long and coiling it up to fit into a small space. The wire resists the current so much that the filament becomes hot enough to glow white. Swan and Edison later set up a joint company to produce the first practical filament lamp. Prior to this, electric lighting had been by crude arc lamps. Edison used his DC generator to provide electricity to light his laboratory and later to illuminate the first New York street to be lit by electric lamps, in September 1882. Edison's successes were not without controversy, however although he was convinced of the merits of DC for generating electricity, other scientists in Europe and America recognized that DC brought major disadvantages.





Michael Faraday

The credit for generating electric current on a practical scale goes to the famous English scientist, Michael Faraday. Faraday was greatly interested in the invention of the electromagnet, but his brilliant mind took earlier experiments still further. If electricity could produce magnetism, why couldn't magnetism produce electricity. In 1831, Faraday found the solution. Electricity could be produced through magnetism by motion. He discovered that when a magnet was moved inside a coil of copper wire, a tiny electric current flows through the wire. Of course, by today's standards, Faraday's electric dynamo or electric generator was crude, and provided only a small electric current be he discovered the first method of generating electricity by means of motion in a magnetic field.

Nearly 40 years went by before a really practical DC (Direct Current) generator was built by Thomas Edison in America.





James Watt

James Watt When Edison's generator was coupled with Watt's steam engine, large scale electricity generation became a practical proposition. James Watt, the Scottish inventor of the steam condensing engine, was born in 1736. His improvements to steam engines were patented over a period of 15 years, starting in 1769 and his name was given to the electric unit of power, the Watt.Watt's engines used the reciprocating piston, however, today's thermal power stations use steam turbines, following the Rankine cycle, worked out by another famous Scottish engineer, William J.M Rankine, in 1859.

A steam engine is an external combustion heat engine that makes use of the thermal energy that exists in steam, converting it to mechanical work. Steam engines were used as the prime mover in pumps, locomotives, steam ships and steam tractors, and were essential to the Industrial Revolution. They are still widely used, particularly for electrical power generation using the steam turbine. A steam engine requires a boiler to boil water to produce steam. The expansionﾑor contractionﾑof steam exerts force upon a piston or turbine blade, whose motion can be harnessed for the work of turning wheels or driving other machinery. One of the advantages of the steam engine is that any heat source can be used to raise steam in the boiler; but the most common is a fire fueled by wood, coal or oil or the utilization of the heat energy generated in a nuclear reactor.



Power Transmission1 ) Power station generators make

electricity at 11000 to 25000

volts. To deliver electricity with

as little waste as possible a very

high voltage must be used. So

transformers at the transmission

sub-station step up the voltage up

to 765,000 volts.

2 ) Electricity can be carried over the

countryside on overhead lines or

underground cables. Pylons over

the ground are ugly but they are

much cheaper to make and erect

than underground cables as you

can see.

3 ) To avoid power cuts caused by lightning,

electricity supply lines are

arranged in an inter-connecting

grid. If one of the supplies to a

factory is cut off, it can still get its

supply from another line.

4 ) When the electricity reaches the second

of the two main substations, it is

still at a very high voltage. Step-

down transformers in the

substation reduce the voltage to a

lower level which is carried on

smaller, lighter pylons.

5 ) The final link in the chain from power

stations to commercial and

residential facilities is the

transmission of the stepped-down

voltage.

Alternating

Current

Alternating current is useful because its voltage can be

changed by using a transformer, which is simply two

coils of insulated wire wound round an iron core.

Although there is no electrical connection between the

two coils, any voltage in the first coil sets up a voltage in

the second coil. This effect is called induction. Larger

or smaller voltages, whatever is needed can be set up by

varying the number of turns in the two coils.

Of the two forms of

electricity, power

stations use

alternating current. To

make alternating

current, powers

stations use

generators that have

coils like an electric

motor. As each coil is

turned between the

two magnets, current

is made the exact

opposite of an electric

motor. But the amount

of current varies as the

coil turns round. The picture above shows you how the amount

of current varies as the coil turns. The turning

coil is shown on the top of the picture. You can

see that when the coil is upright, no current is

made at all. As it turns the current flow begins

to increase, but soon the flow gets smaller

again. After the coil has turned half a circle,

the current starts to flow the other way. Power

stations produce 50 of these two-way cycles

every second.

21st Century Electricity

If we go on using coal, oil and gas as fast as we do now, they could be used up in under 100 years. So scientists are looking for other ways of producing electricity. If you want to help these scientist, tell your friends what you have learned and grow to love and understand the magic of electricity even more.

Difference between Power and Energy

A. Primary Energy: Oil, Coal, Natural and Primary electricity

B. Secondary Energy: Oil --- oil products like diesel and petrol, Coal --- coal briquette and coke

C. Primary Electricity: nuclear, geothermal, wind, HEP (Hydro Electric Power)

D. Secondary Electricity: electricity generated by burning fossil fuels

16

Energy Sources

17

Energy Sources

• Non-Renewable Energy - Energy sources

used faster than can be replenished.

Coal - Oil - Natural Gas

• Renewable Energy - Continuously present as

a feature of the environment (solar energy),

or is continually replenished.

Some forms are referred to as perpetual

energy.

18

All Energy Sources

19

2. What percent of fossil fuels are used?

• Fossil fuels supply 90% of world’s

commercial energy.

– Oil 40%

– Coal 24%

– Natural Gas 25%

20

3. What is the difference between

Resources and Reserves

• Resource - Naturally occurring substance of use to humans that can potentially be extracted using current technology.

• Reserve - Amount of a known deposit that can be economically extracted using current technology, under certain economic conditions.

Reserve levels change as technology advances, new discoveries are made, and profit margins change.

21

Resources and Reserves

22

4. How is coal formed?

• Coal

– 300 mya plant material began collecting underwater, initiating decay, forming a spongy mass of organic material (peat).

Due to geological changes, some of these swamps were covered by seas, and covered with sediment.

Pressure and heat over time transformed peat into coal.

23

Recoverable Coal Reserves

24

5. Types of extraction

• Two main extraction methods:

– Surface Mining (Strip Mining)

Removing overburden on top of a vein.

Efficient but destructive.

– Underground Mining

Minimizes surface disturbance, but costly

and dangerous.

Black Lung Disease

25

Surface mining of coal

• Strip mine

• Eco problem – over burden

– Laws in 1990’s now require ground replacement

26

Surface-Mine Reclamation

27

Deep mining – tunneling for coal

28

Problems with Coal

• Bulky - causes some transport problems.

• Black Lung Disease: Mining creates dust pollution.

• Mining accidents: collapse of tunnels,

malfunctioning machinery

• Ecosystem damage/reclamation efforts

• Burning releases pollutants (C and S).

– Millions of tons of material released into

atmosphere annually.

Acid Rain: Sulfur leads to acid mine drainage

and acid deposition.

Global warming: Increased carbon dioxide

29

Coal Use Issues

• Coal is most abundant fossil fuel.

– Primarily used for generating electricity.

Three Categories:

Lignite

High moisture content - Least desirable.

Bituminous

Most abundant - Most widely used.

Anthracite

Highest energy content - Hard to obtain.

pmel energy source enviroment ghg 1

Documents