World+Energy+Sources+Notes+2011

Back to IB PHYSICS > ENERGY, POWER AND CLIMATE CHANGE > PHYSICS CLASS 2011 COLLABORATIVE NOTES PROJECT You should write notes on the section which is allocated to you. Make sure your notes are easy to understand and include pictures, links and examples where appropriate. Explain the formulas from the data booklet where necessary. On each page, you will see the syllabus references. To write notes, click on EDIT. You can then write, insert files and pictures or links. You could link to useful web resources, java applets etc. You can obtain information from the text books or the Internet. You must login to be able to edit and you must be a member of the wiki. Deon || 8.2 World energy sources Notes 2011 Zac || 8.3 Fossil fuel power production Notes 2011 Bevis || 8.4 Non-fossil fuel power production Notes 2011 Reilly, Luke, Ryan || 8.5 Greenhouse effect Notes 2011 Luka, Antoine || 8.6 Global warming Notes 2011 Ivy, Matteo || =8.2 WORLD ENERGY SOURCES (Zac)=
 * 8.1 Energy degradation and Power Generation Notes 2011

8.2.1 Identify different world energy sources. There are numerous energy sources available to the world, both renewable and non-renewable and at varying levels of efficiency.

Non-renewable energy sources utilize a finite fuel that releases energy when subject something that alters its chemical or nuclear structure, usually heat.

Students should be able to recognize those sources associated with CO2 emission. Students should also appreciate that, in most instances, the Sun is the prime energy source for world energy. 8.2.2 Outline and distinguish between renewable and non-renewable energy sources.

The most common fuel in China is coal, it is made of the dead remains of plants and planktons from aeons ago; compressed by the pressure of the earth into the black lumps of goodness we know and use today. Coal, however, faces the problem of being high in CO2 emissions and as such is environmentally unfriendly, similarly, oil and gas are also non-renewable environmentally unfriendly fuels.

Oil, now the world’s most popular choice of fuel, it is created in a similar way to coal except from the remains of microscopic organisms compressed at the bottom of the ocean. It is easier to extract than coal due to its being liquid, and can be pumped instead of mined.

Wood and biomass, instead of waiting for millions of years for the earth to compress the microscopic corpses of plankton and the remains of dead plants it was seen as lucrative to instead use wood, sugarcane and other plants as fuel. Despite this sounding good on paper these fuels are faced with very low energy density and are thusly inefficient sources of fuel.

Nuclear fuels utilize elements that have unstable nuclei, allowing them to have chain reactions and generate huge amounts of energy. Despite being non-renewable nuclear energy does not produce CO2 or any other greenhouse gases, as such it does not contribute to the greenhouse effect; despite producing harmful, highly radioactive waste.

Fusion fuel, both uranium 235 and hydrogen can be used, both have extremely high energy densities; i.e. a lot of energy can be extracted per kg of fusion fuel.

8.2.3 Define the //energy density// of a fuel.
 * Fuel || Energy density (MJkg-1) ||
 * Fusion fuel || 3*108 ||
 * Uranium 235 || 9*107 ||
 * Petrol || 46.9 ||
 * Diesel || 45.8 ||
 * Biodiesel || 42.2 ||
 * Crude Oil || 41.9 ||
 * Coal || 32.5 ||
 * Sugar || 17.0 ||
 * Wood || 17.0 ||
 * Cow Feces || 15.5 ||
 * Household Waste || 10.0 ||

Energy density is measured in J kg-1 8.2.4 Discuss how choice of fuel is influenced by its energy density

Energy density determines how much energy per kilogram of mass can be extracted, things with low energy density are inefficient to transport and store, and as such are not as appealing to use.

As a race we saw the continued use of these sources non-sustainable and harmful for the world we live in; thus, it was in our best interest to discover and utilize renewable energy sources. Things such as tidal power, geothermal energy, solar power, wind power, wave energy and hydroelectric dams were developed.

Tidal power utilizes the changes in tides caused by the gravitational force of the moon. As the tide changes turbines are driven and thus, produce electricity.

Geothermal energy is the harnessing of steam created by water flowing into hot cracks in the earth’s crust. The creation of steam involves a great release of energy, this and the pressure created when water turns to steam in a closed environment can both be used to drive turbines.

Solar energy is done by mirrors focusing the radiation to a point, the hot spot is then harnessed to power an engine than can do work. Alternatively a photovoltaic cell can be used to convert radiation directly into useful energy.

Hydroelectric power stations use the concept of potential energy gained by water as it is rained upon high places such as mountains, as the water runs down a slope it can be used to drive turbines.

Wind power, through air currents produced by the alternation in heating by the sun energy can be harnessed through the use of wind turbines that turn when blown.

Despite the huge benefits of non-renewable energy the distribution of usage is still heavily in favour of non-renewable sources due to the price efficiency and natural greed of the human race, i.e. people see it in their interest to reap profits from non-renewable energy sources.

The values of energy density of different fuels will be provided. The distribution of energy is thus, Oil – 38% Gas – 23% Coal – 26% Hydroelectric – 6% Nuclear – 6% Geothermal, solar, wind, wood and others – 1%

This is measured in terms of power that each of these methods provides to the world at large.

The obvious advantage of renewable energy sources is that they are renewable, they are infinite. In theory they are perfectly sustainable, however, the reason they are not so widely used is that the technology for them is underdeveloped and overpriced, as such the majority of earth’s population cannot afford to use them and prefer the cheaper alternatives in coal and oil. Furthermore, despite being renewable their efficiency is not especially high and require great amounts of equipment to harness their respective sources. In actuality fusion fuels possess the great energy density and are the most efficient despite requiring a nuclear power station to operate.

8.2.5 State the relative proportions of world use of the different energy sources that are available. The distribution of energy is thus, Oil – 38% Gas – 23% Coal – 26% Hydroelectric – 6% Nuclear – 6% Geothermal, solar, wind, wood and others – 1%

This is measured in terms of power that each of these methods provides to the world at large.

The obvious advantage of renewable energy sources is that they are renewable, they are infinite. In theory they are perfectly sustainable, however, the reason they are not so widely used is that the technology for them is underdeveloped and overpriced, as such the majority of earth’s population cannot afford to use them and prefer the cheaper alternatives in coal and oil. Furthermore, despite being renewable their efficiency is not especially high and require great amounts of equipment to harness their respective sources. In actuality fusion fuels possess the great energy density and are the most efficient despite requiring a nuclear power station to operate.

Only approximate values are needed. 8.2.6 Discuss the relative advantages and disadvantages of various energy sources. The discussion applies to all the sources identified in sub-topics 8.2, 8.3 and 8.4.



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