PHEV Rate of Return Analysis Spreadheet

Attached is a spreadsheet which will calculate your rate of return for a PHEV modification. Please note, that in most cases, this return will be negative.

It asks the following questions to calculate your personal rate of return:

• How much do you expect to pay, on average, for gas while you have the PHEV?
• How much do you expect to pay, on average, for electricity to charge the PHEV?
• How many times can you charge the PHEV battery before it must be replaced?
• How much will it cost to replace the PHEV battery?
• How many times are you going to charge the PHEV per day?
• How many kilowatthours of electricity does it take to charge the PHEV?
• How many miles do you drive per day?
• What mileage do you get out of your stock Prius?
• What MPG do you expect from your car while in PHEV mode (0 for full EV mode or unlimited MPG)
• How many miles do you stay in that mode per charge?
• What MPG will you get when PHEV battery dead? (consider weight of PHEV)
• Cost of PHEV Unit
• Installation Cost
• Sales Tax
• Tax Credit (Usually 10% of PHEV+Installation+Tax)
• Tax refund arrives in 30-day period #
• How long do you plan on owning your PHEV pack (120 month max)
• Residual Value - How much more can sell your prius for because of the PHEV, after you are done with it?
• Guess Rate of Return - If you get an error in the rate of return field, plug in a different guess value.

The fields on the left are answers to the question.
The middle of the spreadsheet shows cash flows and how many charges are left on your battery for each 30 day period.
The stuff on the right is calculated monthly savings.

The spreadsheet isn't perfect, but it's pretty good. If you don't trust downloading the spreadsheet, I have also uploaded it as a google doc at http://spreadsheets.google.com/ccc?key=rWKokgluC9LllCTQbuu8WLQ. However, it is free for anyone to edit, so it may be heavily altered in the near future.

-->Adam