Phys 360 -- Group Project #1
Modeling Car Costs and Incentives for Fuel Efficiency
Download the MS Excel file and open it
Description: The file is for cases (a) and (b) from Activity #5, comparing the Honda Civic LX to the Hybrid with the parameters 10,000 miles/year, 30.5 & 42.5 miles/gallon, and $2.50/gallon. The columns in the file are:
A) year since purchase (t=0 is the moment you drive the car off the lot, it reflects no fuel, only the purchase price; at t=1, we are considering all the fuel used during your first full year of driving; at t=2, all the fuel used in your second year of driving (from t=1 to t=2), etc.
B) Miles driven during year t.
C and I) Miles per gallon, for the conventional and hybrid cars, respectively.
D) Cost of fuel per gallon in dollars (average over a given year, t).
E and J) Total cost of fuel during year t, calculated as E = B/C*D and J = B/I*D (sketch out a unit analysis on paper to convince yourself this equation is correct).
F and K) Total running cost to own and operate the vehicle up to that date, calculated as currentF = previousF + currentE (and for the hybrid, cK = pK+cJ).
G and L) The total amount of carbon dioxide emitted since the purchase of the car, calculated as currentG = previousG + B/C*(124,000 Btu/gallon)/(6500 Btu/lb.co2), and similarly for the hybrid.
N) The difference in the total costs (Hybrid - LX). How is this column related to payback time?\
O) The difference in the total amount of carbon dioxide emitted (LX - Hybrid).
Modeling the Civic LX vs Hybrid:
For comparison, note down the payback time of the Civic LX/Hybrid test. How many miles has each car traveled by the time payback is reached?
Calculate the total amount of carbon dioxide (in pounds) emitted by each car by the time payback is reached.
Do your answers depend on the miles/yr traveled? Devise and carry out a test using the spreadsheet to answer this question; describe the test and your answers.
Take 5-10 min to try out some other parameters for the LX/Hybrid test. Make sure everyone in your group gets a turn operating the spreadsheet. Note down the parameters you test and the results (payback time and total miles traveled by payback). Note: "systematic" testing involves changing one parameter at a time (holding the other variables constant, or "controlling" those variables) and reflecting on the results, so that you can disentangle which effects are due to which causes.
Modeling your chosen conventional vs hybrid vehicles:
First, change the miles/gallon columns to reflect the EPA fuel economy measurements of the conventional (column C) and hybrid (column H) vehicles (note: consider city vs highway driving). Also, change the initial costs (cells F3 and L3) to reflect the purchase price of the vehicles from your research.
Decide on values for the other parameters (miles/yr, $/gallon) and set them in the spreadsheet. Determine (a) the payback time and (b) total miles traveled by payback time. Is the car likely to survive that long?
How much carbon dioxide emission is saved per year by choosing the hybrid over the conventional vehicle? Over the expected lifetime of the vehicle?
Consider the different types of incentives we discussed last class (see Sec. II.5 of the Group Project#1 handout):
- tax credit to offset part of purchase price of hybrid vehicle
- higher tax on gasoline
- implement a tax on carbon dioxide emitted
How will you incorporate each of these into your spreadsheet model? Try implementing them one at a time ("systematically") to see and understand the effect of each possible policy. Then adjust the amount (or "level") at which you implement them to find a payback time that is "reasonable" (that is, that would encourage a buyer to make the high initial investment in the hybrid car). Remember the goal of this group project is to design an effective and fair policy that encourages energy efficient, low carbon emission vehicles.
1) Each group member should spend some time at home using Excel to further investigate the dependence of payback time on the parameters that are relevant to icentives.
2) Each group member should read the following to consider how current policies are used to provide incentives for buying and using fuel efficient vehicles:
- Federal Government’s revised Alternative Motor Vehicle Credit
- Read about gasoline tax rates in different countries on p.46 of our textbook (see the table)
- Read about CAFE standards in our textbook (Focus On 2.1) and from the National Highway Traffic Safety Administration (search on CAFE, or visit here)
During the next class meeting, there will be 15 min for group discussion. During that time, you will discuss your results and decide on key parameters to use in your project writeup: what is the "right" payback time? What parameters will your group use in its spreadsheet tests? What levels are appropriate to get the desired results without becoming burdensome? Prepare your thoughts at home so you can use your time effectively in class to discuss and settle these issues.