This is an INDIVIDUAL assignment. You may discuss it among your teammates, but each of you must write and submit your own tech note. I will be using SafeAssign to check for plagiarism, so be sure to do your own work. President Trump is demanding that the US build “border wall” along the US/Mexico Border. On July 13, 2017, Business Insider (https://www.businessinsider.com/trump-solar-border-wall2017-7) reported that the President suggested that the wall have photovoltaic cells and that the resultant electricity be sold to help defray the cost of the wall. Ignoring the Business Insider details (which may or may not be right) use the following assumptions to perform a Fermi estimate to determine if the cash flow from such a solar wall could pay back the cost of construction over a period of 20 years? 30 years? 40 years? Name one engineering drawback to this approach. Name one political/practical drawback to this approach.
Common assumptions: The wall would be entire length of the US-Mexico Border, 1900 miles.
The wall would be 30 feet high. The cost to construct the wall without solar panels would be $20 million/mile. The cost would be spread over a 10 year construction period, with 1/3 due at the start, 1/3 at the end of the 5th year and 1/3 at the end of 10 years. The interest rate would be current 30 year Treasury Bond rate, rounded to the nearest 0.5%. The cost of the solar panels would be divided in the same way as the cost of wall. One-half of the solar panel capacity would become available at the end of the 5th year, with the remainder being available at the end of the 10th year. You are responsible for estimates regarding the cost of the panels (including installation), the generating capability, the return from sale of electricity, etc. Don’t forget that solar panels only make electricity during hours of full sunlight! It’s a Fermi problem, so I’m not looking for 3 digits of precision! Write me a short (3-5 page) tech note summarizing your computations and answering the questions above. Remember that artifacts (tables, charts, and figures) are “worth 1000 words”. Your writing needs to be professional in quality. Your math needs to be written well (see Rothwell and Cloud). Be sure that your assumptions are clearly stated.
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