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Old 05-12-2012, 09:26 AM   #59
Scooby Specialist
Member#: 95600
Join Date: Sep 2005
Location: Pittsburgh
2003 WRX wagon


Originally Posted by shikataganai View Post
Time to back of napkin it.


- Average gas price over the next 6 years of $4 in today's dollars, which I personally feel is very conservative.
- Average electricity price of $0.10/kWh, also conservative and higher than the current Seattle City Light rates that range between 4.7 and 9.8 cents/kWh, iirc.
- 12k miles/year for each, even though that might be practically challenging to achieve in the EV due to the range.
- V6 4WD RAV4 Limited with navi/Entune as the relatively feature- and performance-matched gas contender, which gets 22 mpg combined and costs $29.9k before destination as described
- Single trim EV model, which costs $49.8k before destination and uses about 0.440 kWh/mile (based off of published Leaf efficiency * scaling factor of 1.2 for weight)
- An EV buyer with an adjusted gross income sufficient to qualify for the full $7,500 Federal tax credit ($55k for a married couple filing jointly), and who lives in Seattle, where EVs are exempt from the 9.1% (iirc) sales/use tax on new vehicles and EVSE is provided free by The EV Project. California's incentives are even more friendly.
- Charger efficiency of 90%, which is more than fair unless one's talking inductive charging

Gas price formula: 12,000 miles x 6 years * $X/gal / 22 mpg, which works out to $13,090 for X = 4.
Electricity price formula: 12,000 miles x 6 years * $Y/kWh * 0.440 kWh/mile / 90% charging efficiency, which works out to $3,520 for Y = 0.10.

Net "fuel" cost savings over 6 years and 72,000 miles = $13,090 - $3,520 = $9,570
Net initial purchase price difference = $49.8k - $7,500 - ($29.9k * 1.091) = $9,679

So the EV breaks even at just over 6 years, and that's before accounting for lower maintenance and increased resale value, the latter of which for used RAV4 EVs has historically been far greater than used gas RAV4s

Despite all this, I still maintain that buying a $50k EV for frugality is a silly idea. If one wanted to be frugal, they wouldn't have been looking at 22 mpg, $30k cars of any sort in the first place, but rather combing the lower cost, more frugal branches of the automotive family tree. Again, though, frugality is not what I'm personally after.
Just so you know 90% is very high for charger efficiency. The tesla packs, which this has use tons of energy rushing fluid around and so forth while charging. Your efficiency will be lower than 90% almost for sure. Also as you said the mileage won't work out, and you don't list a discount rate. Otherwise it seems fine, but the resale for EVs won't stay high if people can buy a new one. The reason the old RAV4 EVs had such high resale is no one could buy one otherwise.
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