1. Cities and Energy, Winter 2006, "What is energy?" What is Energy?

2. Cities and Energy, Winter 2006, "What is energy?" Defining Energy and Its Importance in Describing Human Activity Outline molecules Forms of Energy 1 st Law of Thermodynamics $$$ - A Broader Definition of Energy

3. Cities and Energy, Winter 2006, "What is energy?" Outline 2 nd Law of Thermodynamics To engine Earth oil Principle of Maximum Energy Flow Through for Survival Principle of Maximum Energy Flow Through for Survival Energy and Its Implications for Cities

4. Cities and Energy, Winter 2006, "What is energy?" Forms of Energy Energy in Transition …Moving in and out of systems wind kinetic energy electrical energy out Energy Associated with Mass

5. Cities and Energy, Winter 2006, "What is energy?" Total Energy Associated With Mass i. Potential energy (mgz)g ii. Kinetic energy (1/2 mV 2 ) Velocity iii. Internal energy Forms of Energy

6. Cities and Energy, Winter 2006, "What is energy?" Rotational molecules Total Energy Associated With Mass - Internal Energy Forms of Energy Translational KE molecule electron Vibrational Kinetic Energy molecules Molecular/Chemical Bonds Nuclear Energy

7. Cities and Energy, Winter 2006, "What is energy?" Heat Transfer Energy in Transition Forms of Energy Acoustic transmission, electromagnetic radiation Work – Work due to deformation of a solid Dx F=kdx x W = Force x distance

8. Cities and Energy, Winter 2006, "What is energy?" “Energy can be defined and measured as the ability to generate heat.” Odum and Odum, p. 27 I disagree! Heat or thermal energy is the consequence of our energy inefficiencies. In the industrialized world, the overall efficiency of how we employ energy to enable human processes is about 3.5% efficient, which means that 96.5% of the energy we use doesn’t do anything but transfer to our environment as heat! It seems better to define energy in terms of what is useful to human / biological processes.  Work Defining Energy and Its Importance in Describing Human Activity

9. Cities and Energy, Winter 2006, "What is energy?" Work = Force x Distance (Newton – meter) (Joule) (Pound – foot) Defining Energy and Its Importance in Describing Human Activity

10. Cities and Energy, Winter 2006, "What is energy?" da Vinci Cengel and Boles, Thermodynamics Defining Energy and Its Importance in Describing Human Activity

11. Cities and Energy, Winter 2006, "What is energy?" Cengel and Boles, Thermodynamics Defining Energy and Its Importance in Describing Human Activity

12. Cities and Energy, Winter 2006, "What is energy?" To fuel cell/motor Solar energy Solar photovoltaic panel electrical energy produced water hydrogen Heat Work out Heat

13. Cities and Energy, Winter 2006, "What is energy?" Broader Perspective of “Work” “Energy is a measure of everything. It measures the amount of stored capability for future processes and the rate at which processes go. The total amount of an accomplished process is measured by the enery used.” Odum and Odum, p. 23 Exaggeration? Defining Energy and Its Importance in Describing Human Activity

14. Cities and Energy, Winter 2006, "What is energy?" ProcessEnergy Used Educate 10 students Educate 1,000,000,000 students Feed 1,000 people in the 3 rd world Feed 1,000 people in the industrialized world Provide sewage service to 10,000,000 people in a city Enable 1,000 people to attend the local opera Defining Energy and Its Importance in Describing Human Activity

15. Cities and Energy, Winter 2006, "What is energy?" From a broader perspective, then: Defining Energy and Its Importance in Describing Human Activity “Work” can also be: the ($$$) produced from the use of energy, thus permitting the purchase of additional energy the human processes made possible from the use of energy the products produced by the use of energy

16. Cities and Energy, Winter 2006, "What is energy?" Energy is conserved 1 st Law of Thermodynamics -

17. Cities and Energy, Winter 2006, "What is energy?" To fuel cell/motor Solar energy Solar photovoltaic panel electrical energy produced water hydrogen Heat Work out Heat

18. Cities and Energy, Winter 2006, "What is energy?" Solar energy Solar photovoltaic panel electrical energy produced water hydrogen Heat Sales $$$$ 1 st Law from a Broader Perspective

19. Cities and Energy, Winter 2006, "What is energy?" To engine Earth oil Energy “quality” diminishes with each process 2nd Law of Thermodynamics -

20. Cities and Energy, Winter 2006, "What is energy?" Where the oil, natural gas, and coal came from Photosynthesis Geological Activity + MUCH time Power plant 9000 J8 J heat8992 J heat4 J fossil fuel 4 J 1 J Fossil fuels represent highly concentrated energy! Fossil fuels represent highly concentrated energy! Odum and Odum, 1976 Energy “quality” diminishes with each process 2nd Law of Thermodynamics -

21. Cities and Energy, Winter 2006, "What is energy?" Energy “Cascades” from high entropy (concentration) to low entropy (concentration) Quality of Energy on Earth Solar Oil Coal High Temperature Mass Mass at Atmospheric Temperature There is MUCH more Total Energy Here, But Not Useful Reason: Energy Efficiency There is MUCH more Total Energy Here, But Not Useful Reason: Energy Efficiency Energy “quality” diminishes with each process 2nd Law of Thermodynamics -

22. Cities and Energy, Winter 2006, "What is energy?" Energy Efficiency = Useful energy output / energy input that costs Typical Best Energy Efficiency Solar Fossil fuel / power plant Fossil fuel / I.C. auto 50% ~40% ~20% 0% Mass at Atmospheric Temperature Pre-industrial revolution <0.1% Energy “quality” diminishes with each process 2nd Law of Thermodynamics -

23. Cities and Energy, Winter 2006, "What is energy?" Quality of Energy Materials are also associated with quality of energy 2nd Law of Thermodynamics - $$$$$

24. Cities and Energy, Winter 2006, "What is energy?" gasoline Sales $$$$ 2 nd Law from a Broader Perspective What does the 2 nd Law tell us about the Quality of the energy made avail. with the $$$ generated? Earth oil refinery

25. Cities and Energy, Winter 2006, "What is energy?" Relevance of 2 nd Law to a City?

26. Cities and Energy, Winter 2006, "What is energy?" Energy Source(s) “Interaction process” (production) Storage of high quality energy Production of higher quality energy Heat dissipated in production Feedback work loop depreciation Principle of Maximizing Energy Throughput for Survival

27. Cities and Energy, Winter 2006, "What is energy?" Fossil fuels enabled the formation of cities and the mass migration from Farm to city. Solar Energy Income: 700 Watts/square meter Pre-industrial (oil/coal) age effic.:0.1 % Human energy needs:100 Watts Land needed to support family of 6 (for crops/meat)~2-5 acres required to feed family Pre-industrial Coal, then oil and natural gas, became the drivers for the city. Could transport food and trade goods. Provided alternative career paths; all needing energy. Energy: Implications to the City

28. Cities and Energy, Winter 2006, "What is energy?" MIT, Sustainable Energy Course Energy: Implications to the City

29. Cities and Energy, Winter 2006, "What is energy?" Material Virgin MJ/kg Recycled MJ/kg Aluminum19627 Polyethylene9856 PVC6529 Steel4018 Glass3013 Nylon120.232.1 Wood0.1-2 CSIRO Energy for human support for 1 year = 2500 MJ Car = 2000 kg = 80,000 MJ Skyscraper = 1x10 10 MJ (energy needed by 1 million people per year) Energy: Implications to the City

30. Cities and Energy, Winter 2006, "What is energy?" http://www.eia.doe.gov/emeu/aer/eh/frame.html Energy: Implications to the City

31. Cities and Energy, Winter 2006, "What is energy?" http://www.hubbertpeak.com/curves.htm 1997 2004 M. King Hubbert His prediction in 1956 that U.S.oil production would peak in about 1970 and decline thereafter was scoffed at then but his analysis has since proved to be remarkably accurate.” Energy: Implications to the City