ENV 200 Chapter 5, Fall 2013

Energy Energy • The capacity to do work or transfer heat Solar Capital • Almost all the energy that heats the earth and our buildings comes from the sun at no cost to us. • Without this perpetual, inexhaustible source of energy, the Earth’s average temperature would be -240°C!! • Life would not exist!! Solar Capital Solar Capital Visible light comprises most of the spectrum of electromagnetic radiation emitted by the sun! Energy Transformation Energy Transformation • When driving your car, only 6% of the high quality energy available in its gasoline fuel actually moves the car. • 94% of the high quality energy is released as low quality heat! • 94% of the money you spent on gasoline is wasted!! Energy Efficiency • Also known as energy productivity • A measure of how much useful work is accomplished by a particular input of energy into a system Energy Efficiency Plenty of room for improvement!! Stop wasting energy!! Energy Efficiency in the United States of America Perform useful w ork 16% Unnecessarily w asted 43% Wasted through second law of thermodynamics 41% Energy Quality • A measure of an energy source’s capacity to do useful work; The amount of energy available that can perform useful work – High-quality energy: concentrated; has a high capacity to do useful work • Examples: Very high-temperature heat, concentrated sunlight, high velocity wind, energy from burning fossil fuels – Low-quality energy: dispersed; has little capacity to do useful work • Examples: Amount of heat stored in a large amount of matter (The Atlantic for example) Energy In terms of renewability:  Perpetual Solar, wind, hydroelectric  Renewable  Renewable, but not on human timescales Fossil fuels, nuclear Considered non-renewable for practical purposes Solar Energy • Direct and Indirect • Direct solar energy produces several forms of renewable energy (Indirect solar energy): – Wind (Moving air masses heated by the sun) – Hydropower (Flowing water kept fluid by the sun) – Biomass (Solar energy converted to chemical energy and stored in plants) History of Human Energy Use History of Human Energy Use • Muscle power • Fire as first step along the energy path • Muscle power; domesticated wild animals • Wind and flowing water • Steam engine operated on wood; deplete forests • Coal, then oil • Nuclear energy • Energy crisis History of Human Energy Use • 2000 kilocalories per person per day for hunters and gatherers • Additional 600,000 kilocalories per person per day for modern humans; mainly used by machines and systems that maintain our complex lifestyle Sources of Energy • Commercial energy: energy sold on the market – Non-renewable sources: mainly carbon- containing fossil fuels (oil, coal, natural gas) – We live in a fossil fuel era!! – Renewable sources: wind, hydropower, biomass, geothermal Sources of Energy Sources of Energy Sources of Energy Sources of Energy Energy Consumption Energy Consumption Energy Consumption Energy Consumption Energy Consumption Evaluating Energy Resources • Supplies • Environmental impact • Amount of useful energy provided Evaluating Energy Resources • Any energy resource with a low net energy will need government subsidies to compete in the marketplace with high net energy resources. Fossil Fuels • Dominant source of power!! • High energy content • Efficient to burn, ship and store Fossil Fuels Fossil Fuels Fossil Fuels Unevenly Distributed!! 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 % of World Reserves Coal Oil Natural Gas Fossil Fuel Type US Saudi Arabia Russian Federation Iraq Fossil Fuels Per capita consumption varies!! Developed countries use more than developing countries!! Fossil Fuels Different profiles of energy use!! OECD = Organization for Economic Cooperation and Development Mainly Developed Nations Mainly Developing Nations Fossil Fuels Decreasingly available!! 0 100 200 300 Coal Natural Gas Oil Estimated Reserves (yrs) Fossil Fuel Formation Coal • Most abundant fossil fuel • Organic matter (generally woody plant material) compressed under very high pressure to form dense, solid carbon structures • Burned in 2100 power plants, generates 40% of the world’s electricity Coal Coal Coal Coal • Three largest coal-burning countries – China – United States – Canada Coal Coal Strip Mining Coal Coal Severe air pollution!! • Sulfur released as SO2 • Large amount of soot • CO2 • Trace amounts of Hg and radioactive materials Coal • Single biggest air polluter in coal-burning countries • One-fourth of the annual CO2 emissions • Many opposed to new coal-burning power plants!! • Environmentalists call for – Taxation on carbon dioxide production by power plants. – Cleaner coal-burning plants. CO2 Emissions Per Unit of Electrical Energy Produced for Energy Sources, expressed as % of emissions released by burning coal directly Coal • Conversion of solid coal to – Synthetic natural gas (SNG) by coal gasification – Methanol or synthetic gasoline by coal liquefaction • Are there benefits to using these synthetic fuels? Oil • Also known as crude oil, conventional oil, light oil or petroleum • Most used fuel since the 1960s • Accounts for ca. 40% of the world’s commercial energy consumption Oil Petrochemicals: products of oil distillation Oil Saudi Arabia 13.1 Russia 11.9 USA 8.5 Iran 5.2 Mexico 4.9 China 4.5 Venezuela 4.0 Canada 3.8 Norway 3.9 UAE 3.3 USA 24.9 China 8.6 Japan 6.4 Russia 3.4 Germany 3.3 India 3.2 S. Korea 2.8 Canada 2.6 France 2.5 Italy 2.4 Oil • 13 countries have at least 60% of the world’s crude oil reserves – Saudi Arabia: 25% – Canada: 15% Oil Oil • Organization of Petroleum Exporting Countries (OPEC) controls oil prices! Oil Oil • Possible effects of steeply rising oil prices – Reduce energy waste – Shift to non-carbon energy sources – Higher prices for products made with petrochemicals – Higher food prices; buy locally-produced food – Airfares higher – Smaller more fuel-efficient vehicles – Upgrade of public transportation Oil Oil Spills