Topic: Alternative energy A-level exam

Transcription

1 ALTERNATIVE ENERGY Name: Schneeberger Bernhard Class: 3 / 4 AEB 2000 / 2001 Examiner: Prof. Wurzinger Riedl GREEN Seite 1 von 1

2 Table of contents 1 What is alternative energy? 2 Electricity and the environment: Why should we care? 2.1 Environmental factors 2.2 Conventional energy sources 3 Alternative technologies 3.1 Efficiency 3.2 Solar power Solar thermal power Photovoltaic cells 3.3 Geothermal power 3.4 Wind power 3.5 Low impact hydro power 3.6 Biomass power 4 Pros and cons 5 Words 6 Sources GREEN Seite 2 von 2

3 1 What is alternative energy? Alternative power, or alternative energy is electricity that is produced in a clean way by using environmentally friendly basic material or sources. The basic materials could be renewable ones, like biomass or natural gas. Alternative sources are more or less powered from the sun. For example solar energy, wind energy and all kinds of hydro power. Some others, like geothermal, are powered from the geothermal heat beneath the earth s surface. The target is to minimize all kinds of pollution. But it is not so easy to force alternative energy. As long as commercial power sources (coal, oil, nuclear, hi-impact hydro) are cheaper than alternative energy, people will use comercial sources. Both new techniques have to be developed and environmental factors have to be right to keep the price low. For example, geothermal power could be used almost anywhere at Iceland, but hardly in Austria. 2 Electricity and the environment: Why should we care? Today, the electric power system is the largest single source of industrial air pollution, besides traffic. Conventional sources of electricity harm human health, destroy ecosystems, add to global warming and have high economic costs. Air pollutants are the major cause of asthma attacks to children and grown ups. Billions of liters of water are used to condense overheated steam in thermal power plants. This heated water can devastate fish population and coral reefs. Like el-nino is warming up the sea, which is GREEN Seite 3 von 3

4 caused by the greenhouse effect. Smog, acid rain and heavy metals harm the health of people all over the world. Climatic changes and environmental damage are serious indicators that the status quo is unacceptable. Oil, coal or other petroleum-based recources are called fossil fuels. They are formed by the decayed remains of prehistoric plants and animals. Burning these fuels creates greenhouse gases that accumulate in the atmosphere and allow high level ultraviolet radiation to pass through. Also sulfur dioxide, nitrogen oxide and carbon oxide are released. High impact hydro-electric plants damage their surrounding area with their big dams. Also natural river flows are changed and fish populations are killed. Nuclear energy is produced by causing changes in the nucleus of the atom. There is no air pollution but nuclear plants create dangerous radioactive wastes. They are difficult to dispose and last for centuries. There are no permanent storage sites for this kind of waste. 3 Alternative technologies Efficiency is the cleanest source. Using energy saving services lessens the demand for electricity. Buying economical household appliances and low fuel cars help to keep the environment clean. The sun s radiation is used directly to produce energy, which could be produced in two ways. Solar thermal GREEN Seite 4 von 4

5 and photovoltaic systems. Solar thermal systems use the sun s energy to heat water or transform it into steam. Heated water is used to heat for example a swimmingpool. The steam is used to turn a turbine and a generator, which produce the electric energy. Photovoltaic panels, commonly called solar cells or modules, use semiconductor materials to convert sunlight direct into electricity. These panels are used in remote areas. It is cheaper than stringing miles of electrical wire. The price of solar energy, which was once very high, has dropped by half every five years over the last 25 years. Windmills or turbines are used to produce electricity. Wind power emits no pollution. If care is taken to avoid placing the windmills in undeveloped areas, these generators can have relative little impact on the land. Using wind is economical in areas where the average wind speed is at least 20 kilometers per hour. Although a single wind turbine can produce a usable amount of electricity, most wind power is produced in wind farms. These are large groups of turbines grouped together on a site. Wind power is one of the cleanest sources that can be used. And the cost- power relation is better than for example for solar power. The geothermal heat in deep areas beneath the earth s surface is used to produce overheated steam. This steam can be used to produce electricity or longdistance energy. These plants emit very little air pollution and have minimal impact on the environment. They are also very economical. Energy from flowing water is the oldest form of using power from nature. Low impact hydroelectric plants convert a renewable energy (water flows) into electricity and don t emit any air pollution. Planning the dam carefully may cause new eco-systems for GREEN Seite 5 von 5

6 animals and plants. If dams also have fish ladders and if they fit into the nature, this is a very clean form of energy. Organic material, called biomass, can be burned in an incinerator to produce energy. Biomass recources include agricultural, forestry and food processing byproducts. In new facilities the biomass is converted into a combustible gas. Although biomass produces air pollution, it s a more green and renewable power source than petrol-based fuels. 4 Pros and cons + Using alternative energy and renewable sources helps to reduce harmful emissions to our environment. Then our seriously impacted nature could recover. This will increase quality of life for this and all further generations. - At this time alternative energy is more expensive than con-ventional energy. If conventio-nal power stations will be closed, lots of people will loose their jobs. But if new techniques are invented, and they sell good, prices will be reduced. And one should never forget thinking of our and our childrens environment, even if alternative power is more expensive. 5 Words accumulate agricultural ansammeln landwirtschaftlich GREEN Seite 6 von 6

7 amount average beneath combustible commercial power dam decayed remains demand facilities forestry alternative energy green house effect high impact hydro plant house-hold appliances incinerator long- distance energy low impact hydro plant nucleus remote areas renewable semiconducors status quo storage site to devastate to emit Betrag, Menge Durchschnitt Unterhalb leicht entzündlich althergebrachte Energieformen Kraftwerksdamm verrottete Rückstände Anforderung Anlagenkomplex forstwirtschaftlich Alternativenergie Treibhauseffekt Speicherkraftwerk mit hohem Damm Haushaltsgeräte Müllverbrennungsofen Fernwärme Laufkraftwerk mit niedrigem Damm Kern eines Atoms abgelegene Orte erneuerbar Halbleiter der jetzige Zustand Lagerplatz vernichten aussenden, abgeben 6 Sources GREEN Seite 7 von 7

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9 Wind energy A B C M E D F I G H K L A J A Rotor blades B Hub C Low speed shaft D High speed shaft E Gearbox F Mechanical brake G Electrical generator H Electronic transformer I Hydraulics system J Pillar K Anemometer L Wind vane M Housing GREEN Seite 9 von 9

10 Solar thermal power A - Pool water inlet B - Pump C - Filter D - Check valve E - Gate valve 1 F - Drain valve G - Solar collectors H - Vacuum breaker and auto air relief I - Gate valve J - Fossil fuel heater (if existing) K - Chlorinator (if existing) L - Warm water returns to pool M - Sensor N - Automatic control box O - Electric or constriction valve (collector bypass) P - Booster pump GREEN Seite 10 von 10

11 Photovoltaic system Geothermal energy GREEN Seite 11 von 11

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13 Hydro-power GREEN Seite 13 von 13

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15 Biomass incinerator GREEN Seite 15 von 15

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