Energy the carbon imperative - short version

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Energy the carbon imperative - short version

  1. 1. Energy in Green Building:The Carbon Imperative and the Ruby Slippers Dr. Alexandra “Sascha” von MeierProfessor, Dept. of Environmental Studies & Planning Sonoma State University www.sonoma.edu/ensp
  2. 2. Natural carbon cycle ≈ 50 GtC/y CO2 emissions ≈ 7 GtC/y1 GtC/y = 1 billion tons of carbon per year,which may be bound in CO2 or other compounds
  3. 3. CO2 removal fromatmosphere ≈ 3 GtC/y CO2 emissions ≈ 7 GtC/y
  4. 4. 7 800 3
  5. 5. Burning fossil fuel means combustion of hydrocarbons: CXHY + O2 → CO2 + H2Ohydrocarbon + oxygen → carbon dioxide + waterwhere the proportions of CO2 and H2O depend on X and Y
  6. 6. GISS analysis of global surface temperature; 2008 point is 11-month mean. Source: Jim Hansen, 2008
  7. 7. Five Stages of ReceivingCatastrophic NewsDenialAngerBargainingDepressionAcceptance
  8. 8. Source: Arctic Council and International Arctic Science Committee, www.acia.uaf.edu
  9. 9. Slide: John Holdren
  10. 10. Climate stabilization (at 450 ppm CO2) requires global emissions to peak by 2015and to fall to ~80% below 2000 levels by 2050 Slide: Jim Williams Source: Intergovernmental Panel on Climate Change, Climate Change 2007: Synthesis Report
  11. 11. California’s Big Step Forward: Assembly Bill 32 600 Historical Emissions Inventory 2008 Estimate 500 2020 Goal under AB32 Million metric tonnes CO2e 400 Electricity 300 Transportation 200 2050 Target (EO 03-05) 100 Industry 2050 Goal Executive orderSlide: 0 1990 1993 1996 1999 2002 2005 2008 2011 2014 2017 2020 2023 2026 2029 2032 2035 2038 2041 2044 2047 2050Snuller Price
  12. 12. American Heritage Dictionary, 10th ed.
  13. 13. Physical Meaning of Energy:Energy = the ability to do work Force distance Work = Force · distance
  14. 14. Energy = the ability to do workPotential energy = mgh(mass, gravitational acceleration, height) velocity Kinetic energy = ½ mv2 (mass, velocity)
  15. 15. Examples of EnergyNatural gas in the pipeline (chemical)Gas flame on my kitchen stove (chemical to thermal)Hot water in the kettle (thermal)Electricity in the wall outlet (electrical)Spinning blade of the coffee grinder (mechanical kinetic)Pancakes & maple syrup (chemical)Vase sitting on top shelf (mechanical potential)Vase falling down to floor (mechanical kinetic)Radioactivity (nuclear to radiant)Sunshine (radiant to thermal)Wind (mechanical kinetic)
  16. 16. Because a measurable quantity of energy is conservedduring any conversion of one form to another,it makes sense to give a single name to that quantity.
  17. 17. Matter and Energy Resources“High Quality” means High quality energy: concentrated mechanical, electrical, radiant pure easy to use in an orderly state Medium quality energy: nuclear, chemical“Low Quality” means dispersed impure more difficult to use Low quality energy: disordered thermal (heat)
  18. 18. 2nd Law requires:Some of the chemical fuel energy will be degraded into heat.The amount of mechanical work or electricity produced will be lessthan the fuel input.
  19. 19. Basic lesson:Use energy sources matched in quality with end use needs.
  20. 20. Units of energy: Units of power:calories calories per hourkilocaloriesjoules joules per second = wattskilowatt-hours (kWh) kilowatts (kW)British Thermal Units (BTU) BTU per hourtherms (105 BTU)quads (1015 BTU) Power = energy per unit time
  21. 21. Electric usage 232 kWh $0.11/kWhGas usage 52 therms $0.71/thermConversion factors: 1 therm = 100,000 Btu = 105 Btu 1 kWh = 3,413 BtuQuestions:• Which is my greater energy consumption – electricity or gas?• Which is more expensive per unit energy – electricity or gas?
  22. 22. Electric usage 232 kWh $0.11/kWhGas usage 52 therms $0.71/thermConversion factors: 1 therm = 100,000 Btu = 105 Btu 1 kWh = 3,413 BtuConvert 232 kWh into therms by multiplyingby the conversion factors (3,413 Btu / kWh) and (1 therm / 105 Btu):232 kWh x (3,413 Btu / kWh) x (1 therm / 105 Btu) = 7.9 therms → I use 7.9 therms worth of electricity
  23. 23. $ 0.115 / kWhPG&E electric rates have stayed about the sameover the past five years
  24. 24. $ 1.04 / therm $ 0.92 / thermPG&E gas rates have gone up from $0.70 / therm
  25. 25. Electric rate $ 0.115 / kWhGas rate $ 0.92 – 1.04 / thermWhich is more expensive, gas or electricity?Conversion factors: 1 therm = 100,000 Btu = 105 Btu 1 kWh = 3,412 Btu$0.115/kWh x (1 kWh/3,412 Btu) x (105 Btu/therm) = $3.37/therm→ electricity is over three times as expensive as natural gas
  26. 26. Time for a break, maybe?
  27. 27. Portfolio of renewable energy resourcesProblematic issues:• spatial and temporal constraints on energy availability• requires sophisticated, integrated planningIn my opinion, these are the most readily solvable problems.
  28. 28. Pacific Gas & Electric, 1989
  29. 29. Exclusion zone radius 18 km, area 109 m2Incident solar radiation 1000 W/m2at conversion efficiency 0.1could generate 108 kW or 100 GW of solar powerat capacity factor 0.2 would produce 5% of U.S. electric energy

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