22.0 Energy Tradeoffs Frank R. Leslie, B. S. E. E., M. S. Space Technology, LS IEEE 4/15/2010, Rev. 2.0 (321)

In Other News... Crude oil continues at ~$86/bbl Southwest Windpower will use 3Tier wind mapping below

22 Overview: Trade Studies Trade studies provide decision-making information as to selection of choices The selection of parameters with which to make the choice requires thought and a source of reliable data There is often a tendency to judge the answer as “wrong” if it disagrees with the prejudged answer! Following are a few examples, but there are many more approaches not covered here; search for “systems engineering methodologies” to find others

22.0 Generic Trades in Energy Energy trade-offs are required to make rational large-dollar decisions PV is expensive (~$3.00 per watt for hardware + ~$5 per watt for shipping and installation = ~$8 per watt) compared to wind energy ( $1.50 per watt for hardware + $5 per watt for installation = $6.50 per watt total ) Are Compact Fluorescent Lamps (CFLs) better to use? Ref.: pictures/general/ windfarm/index.asp?i=2 Ref.: on/story/story- images/solar.jpeg Photo of FPL’s Cape Canaveral Plant by F. Leslie,

22.1 How do we trade off choices? Usually, we want the “best” result for the least cost So “all” we have to do is define a “best” score and then compute $/score points! Oh.... sometimes that’s hard!  What does “best” mean anyway? What is “good”? What is “good enough”? What is “nonpolluting”? What is “clean”? What is “green”?

22.1 How do we decide on “best”? If it’s a simple choice like buying gasoline  The usual or typical price is known for stations  Our car should run “without complaint”, and the gasoline shouldn’t cause noticeable service problems  Gasoline is “almost” a commodity (“special” additives/ dyes!)  Price per gallon is the comparison for most of us There may be other nongasoline factors  Where the station is located (don’t drive far away)  Convenience of paying at the pump (slide that card!)  Traffic and getting back on the road  Company is accused of ignoring social justice in South America or Africa (Nigerian Ken Sara-Wiwa) If any of these items are too inconvenient or troubling, we may buy more expensive gasoline elsewhere

22.1 Leslie’s “Best” Restaurant Rule The food is tasty, and the prices are low (or at least not “high” --- a reference to artificial intelligence fuzzy logic) Look for a police car, fire truck, or ambulance outside  Usually means they’re eating there (as opposed to business --- if flashing red lights are off!)  They know all the restaurants around town that they like and don’t like, and they eat out daily  The food is usually good and doesn’t cost much The marginal utility between a “fine cuisine” restaurant and a local “family” restaurant is small Presence of “locals” there indicates they believe they usually get good value for their money (This gratuitous aside brought to you without extra charge)

22.2 Tradeoff Matrices Tradeoff matrices describe key attributes for various choices; a common systems engineering tool There are four main attribute categories: performance, cost, schedule, and risk  There should be approximately equal numbers of each attribute These scores are also known as “Figures of Merit” The attributes should be measured so higher numbers indicate “better” --- high scorers wanted A combination of these FOMs is necessary to get the “one juicy number” that summarizes/ranks the results A spreadsheet is nearly perfect for this work

Weighted Scoring Technique

Trade Matrix Formula

22.3 Difficulties of Selection Some specifications are available to provide necessary information  These “specs” can be entered in the spreadsheet, and a conversion factor developed to change the spec to a score The various scores are then weighted to indicate the relative importance The sum of the weighted scores yields a score that indicates the relative worth of the choice The relative difference of the scores may be trivial, indicating that one is not really better than the other choice; take your pick A significant difference (at the 95% confidence level) may point to selecting one choice over the other

22.3 Value of a Recounted Vote From

22.4 Ranking by “Somehow” Ranking from the best option down to worst sometimes produces focus without specific quantification This approach can suggest two or three choices for extensive examination by the priority thus given The ranking may be done by majority voting of a panel of “experts”  Each person may vote for one to all of the projects If a person likes only one, s/he votes for only that one If s/he likes two of them, s/he votes for both The total of the votes for each alternative then immediately indicates the preferred ranking by the group as a whole without the expense of re-voting (IEEE elects its next president this way)

22.4 Ranking through Pairing Compare pair-wise to find a predominance; point to the best of each pair choice; add/subtract to find net preference for each Option A: 3-2 = +1 (for orange area) Option B: 3-2 = +2 Option C: +2+3 = +5 Option D: 2-3 = -1 Option E: 3-2 = +1 Option F: 0-5 = -5               

22.5 Social Factors and Optimization There are often difficult-to-quantify aspects like beauty of the site, attractiveness, pure “viewscape”, or sound levels that are personal impressions, philosophy The optimization of the site to make it attractive to the public can be a major factor in gaining approval Involving the public in preliminary stages in meetings (charrettes) often can assist in final decisions and provide data to advocate your position Those strongly concerned one way or the other will have come there, thus their opinions outweigh those who didn’t show up (just like in election voting)  Should presidential elections be simplified to simply getting donations to go to the treasury? Most $ wins!

22 Conclusion: Trades Renewable energy faces the same types of problems that affect other areas of daily living  Necessary to get permission to do something different than what is codified in law or local ordinances  Requires convincing the public or government officials that the project is not a public nuisance and will be beneficial to the community Trade studies that produce a well-written report documenting the situation, goals, choices, and selections may help to sway those with the power to approve or disapprove your proposal  Example: Campus Sustainability Practice these trade studies on small projects to be prepared to do the large projects well

Olin Engineering Complex 4.7 kW Solar PV Roof Array Questions?

References: Books Boyle, Godfrey. Renewable Energy, Second Edition. Oxford: Oxford University Press, 2004, ISBN (my preferred text) Brower, Michael. Cool Energy. Cambridge MA: The MIT Press, , TJ807.9.U6B76, ’4’0973. Duffie, John and William A. Beckman. Solar Engineering of Thermal Processes. NY: John Wiley & Sons, Inc., 920 pp., 1991 Gipe, Paul. Wind Energy for Home & Business. White River Junction, VT: Chelsea Green Pub. Co., , TJ820.G57, 621.4’5 Patel, Mukund R. Wind and Solar Power Systems. Boca Raton: CRC Press, 1999, 351 pp. ISBN , TK1541.P , ’2136 Sørensen, Bent. Renewable Energy, Second Edition. San Diego: Academic Press, 2000, 911 pp. ISBN Tester, Jefferson W., Elisabeth M. Drake, Michael J. Driscoll, Michael W. Golay and William A. Peters Sustainable Energy Choosing Among Options. Boston: MIT Press, 870 pp. July 2005 ISBN-10: Tester, Jefferson W. Elisabeth M. DrakeMichael J. Driscoll Michael W. GolayWilliam A. Peters

References: Websites, etc. The charrette process of public involvement Tradeoff analyses Systems Engineering and Life: Designing, Developing, and Maintaining a Permanent Relationship _______________________________________________________________________________________________ ___ Wind Energy elist Wind energy home powersite elist geothermal.marin.org/ on geothermal energy rredc.nrel.gov/wind/pubs/atlas/maps/chap2/2-01m.html PNNL wind energy map of CONUS Elist for wind energy experimenters Site devoted to the decline of energy and effects upon population Federal Energy Regulatory Commission on OTEC systems telosnet.com/wind/20th.html solstice.crest.org/ dataweb.usbr.gov/html/powerplant_selection.html