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Old 03-16-2013, 10:46 PM   #21
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Join Date: Aug 2005
Chapter/Region: RMIC
'18 Pacifica PHEV
'12 RAV4 EV


Originally Posted by bal00 View Post
I just don't see the point in such a half-assed conversion.
Originally Posted by shikataganai View Post
I calculate NG direct cost plus VRA compressor energy cost of 8.6 cents per mile at relatively high Seattle residential NG prices so if the form factor and payload restrictions fit the bill it's certainly cheaper to run than gas or diesel vehicles for high mileage fleets that need to move people off road.
Saturday night cost estimation time, since I already did the math for another thread, the baby is sleeping peacefully between feedings, and I think the numbers are actually somewhat interesting/surprising:

Full assumptions in this post, for the morbidly curious, with the high points being a reasonable guess at CNG system depreciation, $4/gallon gasoline, Seattle residential NG prices as per the quoted post above, and home refueling via a bought-used VRA that doesn't depreciate much after being initially installed. Whew. That's a sentence and a half. Anyway, the point is that I think the assumptions are reasonable.

Given the above then the breakeven point for a Ram CNG relative to a non-CNG Ram lies somewhere around 64,000 miles and 5 years. Note that this breakeven point assumes one places a value of $0 on the intangible aspects of having an alt fuel vehicle, namely environmental somewhat-friendliness, domestic sourced fuel/not supporting dictators overseas, convenience of home refueling, and the lack of being tied to the gasoline grid.

As for me, I actually place a pretty high value on those intangible aspects, as evidenced by my prior electric bike shenanigans, my wife's current Prius, and her EV-in-next-year plans. For ****s and giggles, if we assign those intangibles a value-to-me of just over $100/month then the CNG Ram pays for itself in 3 years and 36,000 miles.

(The real elephant in the closet underlying the above calculations' assumptions is whether I'd be interested at all in a non-CNG Ram 2500. The answer to that would be no. But since I'd rock a Land Cruiser, which is more or less in the same ballpark cost and MPG-wise, I'll let the elephant sidle past without further mention.)
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Last edited by shikataganai; 03-16-2013 at 11:49 PM.
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