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ENERGY PATHS in the ECOSPHERE

ENERGY PATHS in the ECOSPHERE. TREN 1F90 Sustainability, Environment and Tourism. ENERGY. What is it?. ENERGY. Defined as: THE CAPACITY TO DO WORK. What is it? BASIC DEFINITIONS AND LAWS. ENERGY. POTENTIAL ENERGY: Stored energy in all its forms When released, it can do work

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ENERGY PATHS in the ECOSPHERE

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  1. ENERGY PATHS in the ECOSPHERE TREN 1F90 Sustainability, Environment and Tourism

  2. ENERGY • What is it?

  3. ENERGY • Defined as: • THE CAPACITY TO DO WORK What is it? BASIC DEFINITIONS AND LAWS

  4. ENERGY POTENTIAL ENERGY: • Stored energy in all its forms • When released, it can do work Examples: • Coal, oil, gas • Foodstuffs • Rivers and streams above sea level

  5. ENERGY KINETIC ENERGY: • Energy in motion • Energy possessed by moving objects Examples: • Falling leaf • Diving kingfisher • Waterfall

  6. ENERGY • POTENTIAL ENERGY • KINETIC ENERGY ↕INTERCONVERTIBLE ↕

  7. Laws of Thermodynamics All energy follows basic laws of thermodynamics, central to the understanding of ecological processes and environmental issues.

  8. Laws of Thermodynamics FIRST LAW: Energy can be neither created nor destroyed – it can only change form.

  9. Laws of Thermodynamics SECOND LAW: During transformations, energy goes from a concentrated form to a less concentrated form. Less concentrated energy is dissipated in the form of heat.

  10. Laws of Thermodynamics HEATis the inevitable byproductof energy transformations

  11. Laws of Thermodynamics HEAT COAL ↓ Burned to generate electricity ↓ Transmission of electricity through wires ↓ Lighting of bulb filament ↓ Light energy

  12. Laws of Thermodynamics HEAT • May be defined as the kinetic energy associated with the random motion of atoms and molecules

  13. Laws of Thermodynamics HEAT • Useful in concentrated form (e.g., internal combustion engine), but generally dissipated to the environment in a dilute form

  14. ENERGY CONCEPTS ENERGY QUALITY • The ability of a given form of energy to perform useful work • Also called energy density • High quality energy sources are concentrated (large energy content per unit of measure)

  15. ENERGY CONCEPTS ENERGY QUALITY: All energy sources are degraded in quality with use, to a less useful form (heat)

  16. ENERGY CONCEPTS ENERGY QUALITY: All energy sources are degraded in quality with use, to a less useful form (heat) ↓ Wise energy use requires careful matching of energy source with needs

  17. ENERGY CONCEPTS Matching of energy source with needs: Use low quality energy for low-grade needs • E.g., passive solar radiation for heating living spaces Use high quality energy for high-grade needs • E.g., electricity to weld steel in industrial arc-welding

  18. VERY HIGH HIGH MODERATE LOW Electricity, nuclear fission Natural gas, gasoline, coal, concentrated sunlight Geothermal, biomass, tar sands, oil shale Wind, ambient heat ENERGY DENSITY / QUALITY

  19. ENERGY EFFICIENCY • The ratio of useful energy output to the total energy input.

  20. ENERGY EFFICIENCY Internal combustion engine in car Energy in 1 litre of gas: 6500 kcal Energy output from engineconsuming 1 litre of gas 1300 kcal Energy efficiency: 1300 = 0.20 = 20% 6500

  21. ENERGY EFFICIENCY Incandescent light bulb Every light bulb consuming 100 w of electricity radiates 5 w of visible light energy and 95 w of heat ↓ Incandescent light bulbs are about 95% efficient as heaters, but only 5% efficient as light sources!

  22. NET ENERGY Total energy available in a given source minus the energy used to find, concentrate, and deliver energy to the user

  23. NET ENERGY Tar sand oil extraction process Tar sands mined in open pits; Hot water and steam used to liberate oil ↓ Energy costs of extraction may be up to 80-90% of energy recovered ↓ Net value of extracted oil is only 10-20% of the oil’s true energy content

  24. NET ENERGY Food productionin industrial nations High yield agriculture requires large energy subsidy (fossil fuels for machinery and fertilizer production) ↓ Though total crop yields per hectare increased, the ratio of food energy produced to fuel energy used actually decreased through the mid- to late 20th century

  25. Ethanol fuel production • Ethanol (a renewable alternative fuel) is produced primarily from corn • Corn ethanol requires fossil fuel inputs for production (industrial agriculture) • Net efficiency of ethanol was quite low prior to 1990s-> research shows it takes more fossil fuel energy to produce than the energy it yields • Artificially high price of corn due to fuel use causes increased global food costs and contributes to famine and food shortages

  26. Ethanol fuel production • nitrogen fertilizers • irrigation pumps • gas + diesel fuels • machinery (including energy costs of manufacture) • drying of harvested corn • seeds (includes all inputs required to produce the seeds) • phosphorus fertilizers • herbicides • Pimental et al. (1990) in Carrol et al: Agroecology Main fossil fuel inputs in US corn production are:

  27. Ethanol fuel production • Efficiency may have improved in past 20 years: 1991: 24% 1998: 36% 2001: 67% • Shapouri (2004): attributed to technological advances in farming and manufacturing Source: Shapouri, Hosein. 2004. The 2001 net energy balance of corn-ethanol. www.usda.gov/oce/reports/energy/net_energy_balance.pdf

  28. Ethanol fuel production • Results vigorously disputed by some authorities “About 30 percent more fossil energy is required to produce a gallon of ethanol than you actually get out in ethanol” – David Pimental, 2006, cited in Ratigan, Dylan: Ethanol as gas replacement: Hope or hype? MSNBC On The Money, 23 May 2006 (http://www.msnbc.msn.com/id/12934470/ )

  29. Hope or hype? MSNBC On The Money, 23 May 2006 (http://www.msnbc.msn.com/id/12934470/ )

  30. Ethanol fuel production • Ethanol subsidies called ‘catastrophically idiotic’ (Drum, 2012) • Corn ethanol “worse than gasoline" for environment • Corporate handout gave $0.45/gallon to ethanol producers and fuel blenders; cost taxpayers $6 billion in 2011 • Subsidy expired at end of 2011 • Replaced by revised 2007 Renewable Fuel Standard legislation, under the Energy Independence and Security Act (EISA)

  31. Ethanol fuel production • RFS program: U.S. govt. mandates that >37% of the 2011-12 corn crop be converted to fuel ethanol and blended with the gasoline that powers U.S. cars • Profits go to agribusiness (corn production) and big oil (fuel blenders). 10% of farms (largest) collected 74 per cent of all subsidies between 1995 and 2010. • upshot: ethanol subsidies didn't go away after all; they are just hidden a bit better! - Drum, Kevin. 2012. Ethanol Subsidies: Not Gone, Just Hidden a Little Better. Mother Jones

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