What do you estimate to be the current cost per watt over
the life of a coal, oil, gas or nuclear fueled facility
(build, operate, fuel and decommission)?
"It's tough to make predictions, especially about the future." --
Yogi Berra
I'm afraid I have no easy answer--that question entails a bunch of
assumptions about construction costs, interest rates, the price of
oil, politics, etc. AIUI utilities are traditionally insulated from
these factors by guaranteed profit provisions in the laws that govern
them; it's kind of a cost-plus deal.
I've seen a really good treatment of the question for nuclear power on
Wikipedia somewhere.
As a rough estimate of historical costs we can look at our power
bills--mine indicates the local cost-of-generation is 4.3 cents / kWh,
or $43 x 10^-6 per watt-hour.
Assuming that figure includes all maintenance, fuel, construction,
decommissioning, the cost of money, etc., and that the plant lasts 30
years, the cost of producing 5 Wh/day (the average output of a 1w
solar cell) comes to 5 * 43 x 10-6 * 30 * 365 = $2.35.
In fact, solar power won't be available every day, so solar cells'
output could be matched for less cost, by whatever availability factor
you wish to assume. Also, the cost of new plants may be higher (or
lower) than historically, but this guess is at least a first-order
approximation in today's dollars that includes historical inflation,
etc.
Assuming a 20 year life and 300 day-per-year availability, a $6/watt
solar cell costs $6/ (5 hours * 300 days * 20 years) = $200 x 10^-6
per watt-hour.
That solar-cell figure EXCLUDES two substantial costs:
1) maintenance, battery changes, etc., and
2) the cost of money (i.e., the interest cost on a large up-front
investment).
Obviously I erred above when I said $2 was 3x the utilities' COG. I
_should've_ said their COG is only 1/3rd of your bill, so their break-
even point is 1/3rd of the consumer's break-even point.
Best wishes,
James Arthur