1. Objectives Responding to TDRs Evaluating renewable source of energy Designing for renewables Field Trip 5/2 City Hall – meet in entranceway at 12:45 pm

2. TDR responses Read them through once Put them aside No point getting defensive about them Use them to inform your presentation and prepare your final draft Do not worry too much about grades Peer evaluations count for a relatively small part of your draft grade Even my evaluation only counts for 10% of final project grade

3. Responding to TDRs You do not need to provide a response to small changes in the text You do need to respond to every numbered comment (and all other major comments) stating: Either how you addressed the concern Or why you don’t need to address the concern The reviewer is always “right”

4. TDR response example Figure 4 is not integrated into the text of the paper. A further description and definition of key terms in the figure would make the paper stronger. A longer caption explaining the figure has been added as has an additional sentence in the body of the paper elaborating the conclusions from this figure.

5. TDR responses 1 per reviewer (including me) Due 5/4 when final reports are due. TDR responses are worth 5% of project grade Final report is worth 30% of project grade

6. Defining renewables Difference from earlier discussions Discussing global, rather than just US Solar Wind Biomass Tidal Geothermal Small hydro

7. Solar Solar thermal

8. Solar PV

9. Analysis of solar potential 1350 W/m 2 from the sun (annual average) 300 – 400 W/m 2 on the surface of the Earth Efficiency to conversion to electricity 1 – 10% Transmission losses Inversion losses Storage losses Efficiency for thermal systems 20 - 35 % Pump losses, standby losses

10. Wind turbines

11. Analysis of wind potential E = ½ m v 2 W = ½ Q ρ v 2  v 3 Wind speed is most important parameter Area of blades also a factor Losses Regulating speed/inversion Variable direction/speed Efficiency not as meaningful as output

12. Biomass Combustion (not generally considered renewable) Digestion to produce methane for burning

13. Tidal power

14. Geothermal power

15. Why small hydro and not big hydro? Much smaller effect on streams/rivers No damming required Silting Sedimentation Dam failure

16. Potential (with current technology) ResourcePotential (TWh/year) Output (TWh/year) Wind20-40K50 Solar12-40K1.2 Geothermal4-40K44 Biomass8-25K185 Wave/Tidal2-7.5K~0 Small Hydro?15 Reference: Gross et al. (2003) Environment International

17. State of the art Currently ~356 TWh/year with renewables ~15,000 TWh/year of electricity generation Not reaching our full potential Reasons?

18. Costs of renewable electricity What are average costs for nuclear, coal, gas electricity? FuelCost US¢/kWh Solar30 Wave9 Biomass6 Wind5

19. Successes Wind Since 1990 annual energy output/turbine has increased two orders of magnitude Maximum capacity has increased by factor of 20 (up to ~1 MW) Weight/capacity has decreased by factor of ~2 Sound levels have decreased by factor of ~2 Installed capacity has increased order of magnitude Reference: Gross et al. (2003) Environment International

20. Future for wind Offshore installations Why is this desirable?

21. Solar PV Capacity has increased by factor of ~5 since 1990 Price/peak watt has decreased over an order of magnitude over the last 25 years Efficiency has increased by a factor ~2 over 25 years

22. What are the downsides of renewables Intermittency Strain on grid Local problem Peak power issues Energy storage Additional transmission for offshore capabilties

23. What is the situation in the US? “Renewable energy consumption for 2001 dropped to its lowest level in over 12 years, accounting for just 6 percent of total U.S. energy consumption.” http://www.eia.doe.gov/cneaf/solar.renewables/page/rea_data/chapter1.html Why? What is included?

24. More about renewables in the US Usage by fuel and sector (1997-2001) http://www.eia.doe.gov/cneaf/solar.renewables/pag e/rea_data/table2.htmlhttp://www.eia.doe.gov/cneaf/solar.renewables/pag e/rea_data/table2.html Solar shipments http://www.eia.doe.gov/cneaf/solar.renewables/pag e/rea_data/table10.htmlhttp://www.eia.doe.gov/cneaf/solar.renewables/pag e/rea_data/table10.html Renewable consumption by state http://www.eia.doe.gov/cneaf/solar.renewables/pag e/rea_data/appendixc.htmlhttp://www.eia.doe.gov/cneaf/solar.renewables/pag e/rea_data/appendixc.html

25. Central question is one of cost and political will Populations are often willing to pay for renewable power Captures imagination more than energy conservation Detractors include Entrenched energy interests Operation and maintenance experts Economists

26. Designing for Renewables Match renewable to load Educate clients Make conservation more exciting Plan for energy storage