Energy and Fuel Types

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ENERGY AND FUEL TYPES 1

Energy and Fuel Types

Jisung Moon

Pensacola High School

IB Physics

May 10, 2012

Mr. Bobbitt


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Abstract

Different sources of energy were examined in this investigation. Examining efficiencies,

environmental problems, and costs of the different power sources give reasons for the

widespread or limited use of the fuel sources. Additionally, concepts of the transfer of energy

and energy loss, visually represented by sankey diagrams, demonstrate how many variables must

be actually taken into account to accurately calculate real life problems.


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Energy and Fuel Types

Ever since the industrialization of our world, humans have come to become dependent on

electricity, which is in turn dependent on energy. As a result, the production of energy has

become vital to sustaining the way of life for most people living in MEDCs (More

Economically Developed Country). Fossil fuels, nuclear, solar, hydroelectric, wind, and wave

power, the different sources of energy exploited for the use of human consumption through

electricity, all have their benefits and detriments. The evolution of producing and using energy

from different fuel sources has been motivated by a desire for better efficiency, and more

recently, greener energy stemming from scares of global warming, now identified as ClimateChange.

Fossil Fuels

With the beginnings of mechanization in the 18 th Century during the industrial revolution,

energy became high in demand. Fossil fuels including coal, shale, oil, and natural gas were the

first to be used due to their abundance, high energy density, and relative ease to convert into

useable energy. Although still widely used, in modern times, the use of fossil fuels has been

shunned by environmental groups for its high carbon dioxide emission.

Fossil fuels are made up of dead organic matter, continually exposed to high temperatures

and pressure for millions of years. The chemical energy stored by the dead plant matter which

makes the coal, shale, oil, or natural gas is released when burned, thereby creating thermal

energy which is then used to make steam turn a turbine to finally be converted into electrical

energy (Kirk, 68). (See figure 1.)


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Coal is not only the most widely used source for energy for electric generation but also

the longest used. With an energy density of 22 MJ kg -1, coals efficiency is about 35% (Kirk, 67-

8). Coal is the single largest contributor of CO 2 emissions worldwide ( www.eia.doe.gov).

Transportation costs of coal have been steadily decreasing over the years. (Figure 2.) The Energy

Information Administration estimated that the cost to transport one ton of coal for one mile was

about $12 USD.

While coal is abundant, enough to last humans at least 119 years (www.worldcoal.org/),

relatively cheap, and easy to convert to electrical energy, it has been criticized for its detrimental

effects on the environment. Digging and burning coal causes the release of harmful gases such asmethane and pyrite. This results in acid rains and interference of water tables. Many countries

are converting to the use of greener renewable energies as a result.

Much like coal, shale, oil, and natural gases are fossil fuels that are used to generate

electricity. All four are burned in an electric producing power plant. (Figure 1.) However, oil and

natural gases have higher energy densities and efficiency rates. (Table 1 and Table 2.) Shale has

a much lower energy density however. The cheap price of coal compared to oil and gas has kept

coal at the top in usage. The transportation costs of coal is also much cheaper than that of oil,

shale, or natural gases.

Historically, oil, shale and gases have been behind coal production because people were

already using coal, and the institution of coal had already been placed. Not only that, but

transportation issues and designs changes and the development of such equipment to convert

these fossil fuels into electricity was costly. Political factors were also a likely cause in the

restraint of use of other fossil fuels. (http://www.anl.gov ) As time passed, these fossils fuels

became used, but coal is still the most widely used fuel form. (Figure 3.)


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Nuclear

Instead of burning a fuel to create steam, nuclear power is unique in that it uses fission

reaction to create high temperatures to boil the water, usually through a PWR or pressurized

water nuclear reactor. A clean, CO 2 -free source of energy, nuclear energy is highly efficient and

considered the best way of generating electricity in terms of being green and cost effective. The

extremely high energy density, a staggering 90,000,000 MJ kg -1, is just one reason for its

efficiency (Kirk, 67). (Table 2.) Transportation costs would be minimal as Nuclear Energy does

not needs larges masses of Uranium, unlike coal, where tons of coal is needed for burning.

Because there is no burning, nuclear power does not emit harmful gases into theatmosphere and is environmentally clean, except the waste that it produces, which is stored in

containers. Recently, the military has been experiment with uses of the nuclear waste in order to

recycle it (www.nirs.org/) . Although environmentally friendly, if anything should go wrong,

there would be monstrous catastrophe, as seen by the Chernobyl disaster.

Nuclear power was not used in the early stages of industrialization because there was no

technology to harness nuclear power. Of course, limited knowledge of nuclear physics did not

help either.

Solar Power

Solar power is one of the recent ways of generating electricity. Solar power has become

popular mostly through green energy activists and the advancement of science which allows for

such devices. A renewable, free energy source, as the energy comes from the sun, solar power is

very clean, although chemicals used to make PV cells and solar heaters is a valid argument

against solar energy being completely green (Kirk, 71). PV cells or Photovoltaic cells and active

solar heaters are the two main ways solar power is harnessed.
http://www.nirs.org/http://www.nirs.org/


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A Photovoltaic cell harnesses solar energy by taking the solar radiation and converting it

into electrical energy using semiconductors. (Figure 5.) Although recent advancements in

technology have made PC cells capable of a 42.8% efficiency, the average efficiency of a PV

cell varies between 12% to 24%, depending on the company and model. (http://www.alt-

energy.info).

An active solar heater uses solar radiation to heat water which is running through a pipe

within the panel. (Figure 6.) The hot water could be used if it were in homes or converted into

steam to run a turbine generating electric energy.

Solar energy is however limited by the visibility of the sun and is unreliable. Besides thefact that the sun is out only during the day, cloudy or rainy conditions even further prohibit the

use of solar energy (Kirk, 71). Also, solar energy has a very lower energy density and requires

large areas for industrial purposes.

Hydroelectric

Hydroelectric power uses the potential water of water due to gravity. Hence,

hydroelectric energy is a clean, renewable source of energy (Figure 10.) which does not involve

harmful chemicals like solar cells. Dams are often associated with hydroelectric power plants.

Although dams do use hydroelectric power, it is not the only power scheme that can harness

hydroelectricity. There are 3 main types of hydroelectric power sources, the tidal, pump, and

lake, the lake scheme. All three are similar in that they convert the potential energy of water into

kinetic energy to turn a turbine. (Figure 7.)

The lake scheme uses the natural water cycle to fill up reservoirs which can be used

whenever needed. The tidal scheme stores the water during a high tide and releases the water

during the low tides. Lastly, the pump uses a pump to pump water back up. However, for it to be


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an efficient system, the system must produce enough energy to power the pump and have excess

energy to generate electricity.

While there are no environmental hazards, building structures to harness hydroelectric

power such as dams requires a shifting of the landscape which in the long term may completely

change the area. In the case of the Three Gorges Dam in China, over 3 million people had to be

displaced so that it could be built. Due to environmental concerns, dams are no longer built in the

US.

The energy density of water depends on the rate of the flow of water as well as the height

of water since the potential energy comes from gravity, where PE=mgh. Therefore energydensity varies for different dams as well as the three different type of hydroelectric power. This

means that the efficiency of hydroelectric systems would also vary.

While hydroelectric power started being used near the 1900s, water has been used for

several centuries to perform work. There are accounts of the Ancient Romans using pumps as

well as gravity to work their aquifers, to supply cities with fresh water. Waterwheels have also

been used by people to power mills.

Wind

Through giant turbines, wind energy can be converted into electric energy. The giant

turbines (Figure 8.) are much like windmills. However, the blades of a modern turbine is used to

run a generator to make electric energy. A renewable and clean form of energy like

hydroelectric, it produces no carbon dioxide and other harmful gases.

Wind energy is derived from solar energy which gives wind its KE. That KE of the wind

is used to turn a turbine, and the KE of wind transfers into the KE of the turbine which in turn

becomes electric energy thanks to a generator. (Figure 8.)


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While the efficiency of wind can go up to 50%, wind energy is unreliable because it is

not always windy, although the turbines are placed in areas of high wind speeds. The cost of a

turbine is extremely expensive, as is the transportation costs. Having to use trains or large trucks

to carry the huge blades. The costs of the generator, blades, and actual parts of structure are often

enormous sums. (Figure 11 and 12.)

Wave

Wave energy also uses the water, but unlike hydroelectric energy, it does not use gravity,

but wave or tidal forces. Wave energy is most successfully harnessed by an OWC, or oscillating

water column. Explained in figure 9, wave energy is also a clean renewable energy source.Due to the extremities and variances of waves, energy density varies depending on how

strong and how constant the waves are. However, it has very low efficiency rate. Using the Wells

turbine, it gets about 0.7 to 0.4 efficiency.

Conclusion

No energy source will dominate another source completely. Because each energy source

has its pros and cons, all energy sources will advance, some more than others. For example,

while nuclear energy is highly efficient and green, the nuclear waste becomes a problem. While

wind energy is clean and renewable, it is unreliable and to some people ugly against the

countryside or the sea, as is the case in Europe. One thing is certain, as long as man continues to

live, he we crave for energy and better ways to harness energy will be found.


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References

Physics for the IB Diploma by Tim Kirk

http://www.eia.doe.gov

http://www.worldcoal.org/

http://www.sankey-diagrams.com

http://www.barnardcastleschool.org.uk/

http://www.oncor.com

http://www.world-nuclear.org

http://www.nrc.gov/reactors/bwrs.html http://www.pesa.com.au

http://www.nucleartourist.com/

http://www.anl.gov/

http://www-pub.iaea.org/MTCD/publications/PDF/te_1584_web.pdf
http://www.eia.doe.gov/http://www.eia.doe.gov/http://www.worldcoal.org/http://www.worldcoal.org/http://www.sankey-diagrams.com/http://www.sankey-diagrams.com/http://www.barnardcastleschool.org.uk/http://www.barnardcastleschool.org.uk/http://www.oncor.com/http://www.oncor.com/http://www.world-nuclear.org/http://www.world-nuclear.org/http://www.nrc.gov/reactors/bwrs.htmlhttp://www.nrc.gov/reactors/bwrs.htmlhttp://www.pesa.com.au/http://www.pesa.com.au/http://www.nucleartourist.com/http://www.nucleartourist.com/http://www.anl.gov/http://www.anl.gov/http://www-pub.iaea.org/MTCD/publications/PDF/te_1584_web.pdfhttp://www-pub.iaea.org/MTCD/publications/PDF/te_1584_web.pdfhttp://www-pub.iaea.org/MTCD/publications/PDF/te_1584_web.pdfhttp://www.anl.gov/http://www.nucleartourist.com/http://www.pesa.com.au/http://www.nrc.gov/reactors/bwrs.htmlhttp://www.world-nuclear.org/http://www.oncor.com/http://www.barnardcastleschool.org.uk/http://www.sankey-diagrams.com/http://www.worldcoal.org/http://www.eia.doe.gov/


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Appendix

Figure 1. The process of energy transformations for fossil fuels.

Figure 2. Transportation costs of Coal.


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Figure 3. A pie chart showing which fuels were used percentage wise for worldwideconsumption of fuel and as a source for the generation of electricity.

Figure 4. This is a diagram of a nuclear reactor and how it uses fission reactions to makeelectricity.


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Figure 5. This diagram shows how the use of semiconductors converts solar radiation intoelectricity.

Figure 6. A diagram of how an Active Solar heat uses the suns energy to heat water which isused to generate electricity.


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Figure 7. Transfer of energy in hydroelectric power.

Figure 8. Transfer of energy in wind power.


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Figure 9. A diagram of a oscillating water column shows how wave power is harnessed.


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Figure 10. This diagram shows how fuel is not a factor in hydroelectric dams. With the increasein fuel prices, other energy sources become more expensive to produce, but increase in fuel

prices does not have any effect for hydroelectric energy.


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Figure 11. The cost of blades of a wind turbine.


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Figure 12. Costs of land wind turbine.


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Figure 13. Sankey diagram of Coal

Figure 14. Sankey diagram of Oil


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Figure 15. Sankey diagram of Wind

Figure 16. Sankey diagram of Nuclear


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Figure 17. Sankey diagram of PV cell


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Figure 18. Sankey diagram for natural gas

Figure 19. Sankey diagram for Coal, Oil, Gas, Nuclear, Hydro, and other renewables

Energy and Fuel Types

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