Re: Electric car economics

"BobG" <bobgardner@xxxxxxx> writes:
>PV:
>If someone can tell me what the KWH per mile would be for a vehicle
>with performance similar to a modern subcompact,
>I'll work out some numbers for it.
>============================
>30mi/gal->.0333gal/mi->.203lb/mi(@6.1lb/gal)->3050BTU/mi(@15000BTU/lb)->.8939KWhr/mi
>(@3412w=1KWhr)
>Off the top of my head! Good memory!

Neat - about 1 kwh per mile. Let's build the system for 50 miles per day
(actually not quite good enough for me, I drive 60), so we would need to
procure 50kwhr per day. Off the grid, that's going to cost about $4.50. Wow,
that's not bad at all, a bit cheaper than gas on a fuel-only basis. That
said, an actual car is probably not going to be this efficient, is it? It
would be nice to have some real-world Kwhr numbers from an existing EV. But
I'll run with it - it goes with my pattern of picking optimistic values.

So, how much would a PV system cost? Here's some numbers, based on the
information from http://www.solar-electric.com/solar_system_costs.htm:

Hours of usable sunlight per day (I used a fixed system in Tuscon, AZ): 6.59
Wattage needed = 50000 / 6.59 * 1.15 = 8,725 watts!

Cost estimate (do it yourself) 8,725 watts * $9 per watt: $78,525. It will
take 47 years for this system to pay back just the installation costs, when
compared to the $4.50 you'd spend per day on simply recharging from the
grid. But it's actually worse than that. Batteries need replacing every 20
years or so, and the panels lose about 1% of their capacity per year. Add
in maintenance of say, 5% of the purchase price per year, and you are
totally screwed. You'll never reach profitability. My guess, that it would
take more than a decade even if prices drop to a sixth of what they are
now, is pretty close. This is a boneheaded choice no matter how optimistic
you make it.

Another fun thing - 8,725 watts is a LOT of solar panel. Using the best you
can buy today at $4.50 per watt (210 watt Sanyo HIT panels), that's 860
square feet of panel, weighing in at 1,353 pounds. Not pretty. *
--
* PV something like badgers--something like lizards--and something
like corkscrews.
.

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