Hybrid Car – More Fun with Less Gas

80 cents / kWhr

register ::  Login Password  :: Lost Password?
Posted by hubops on April 5, 2010, 9:00 pm
 


Let's see if Ontario's <micro> solar industry
takes off  ...

http://microfit.powerauthority.on.ca/

The sellers are saying under 10 year payback
on investment - at todays prices.
 ~ 80 grand for 10 kw should earn ~ 10 grand per year (they say)
.. I wonder how much the 80 grand will buy in a few years, though ..?
John T.



Posted by Josepi on April 6, 2010, 3:53 am
 


Well let's see. (how many time we have to do this for financially challenged
people)

$0K x 5% per annum (lost) = $000.00 per anum lost investment income.

oooops... they are short about $2K over the eight years.

It's not like they are sales people...are they?

--------------------------
10kW x 180 days x 4 hours = 7200kWh (generous in Ontario) x $.81 (roof
mount price) = $832 gross/annum
 less $000/annum in investment loss / interest
------------------------------------------------
$832 per annum net (no maintenance/ batteries/ electronics / rust /roof
damage figured in)

$0K / $832 = 43 years payback with no maintenance. Most of us will never
live to see the break even point.
----------------------------------

$0K sounds a little high though. Maybe about $0-50K??




Let's see if Ontario's <micro> solar industry
takes off  ...

http://microfit.powerauthority.on.ca/

The sellers are saying under 10 year payback
on investment - at todays prices.
 ~ 80 grand for 10 kw should earn ~ 10 grand per year (they say)
.. I wonder how much the 80 grand will buy in a few years, though ..?
John T.





Posted by vaughn on April 6, 2010, 11:42 am
 



It looks like you are also financially challenged, because the calculation is
not nearly so simple.  As the project pays for itself, the investment gradually
decreases, just like the declining balance on your mortgage, so the "Cost of
Capital" should gradually decrease over the years.  That said, it must "save"
more than the cost of capital or the time for payback approaches infinity.

Also, those calculations almost never seem to include maintenance or the
decreasing efficiency of the PV panels as they age.

Vaughn



Posted by Josepi on April 6, 2010, 3:35 pm
 

That would be financially **knowledge** challenged

"As the project pays for itself"

Typically these projects do **NOT** pay for themselves so there won't be any
"declining balance", once the real picture is had, and I didn't mention the
maintenance costs, as they are undetermined, due to lack of good historical
maintenance data on PV systems. I was also trying to keep it simple for
simple friends.





It looks like you are also financially challenged, because the calculation
is
not nearly so simple.  As the project pays for itself, the investment
gradually
decreases, just like the declining balance on your mortgage, so the "Cost of
Capital" should gradually decrease over the years.  That said, it must
"save"
more than the cost of capital or the time for payback approaches infinity.

Also, those calculations almost never seem to include maintenance or the
decreasing efficiency of the PV panels as they age.




Posted by vaughn on April 6, 2010, 5:36 pm
 



Yes, I mentioned that possibility. I wrote: "That said, it must "save" more than
the cost of capital or the time for payback approaches infinity"  As it turns
out, I own a small PV system myself that makes no economic sense.  I consider it
part hobby and part of my hurricane preparations.


One thing that we can safely assume about the maintenance cost is that it will
not be zero.  We know about how long most consumer electronics lasts, and we can
estimate the hazard due to storm damage etc.  So just as you assumed a perfectly
reasonable cost of capital (5%), you can also assume a reasonable allowance for
maintenance and include it in your calculations.  Keep in mind that a
roof-mounted PV system will probably need to be re-installed at least once in
its lifetime due to normal re-roofing.

There are financial programs built into business calculators and spreadsheets
(Net Present Value & Internal Rate of Return) that can help you calculate these
cash flows so you can make a more informed buying decision, or you can simply
model the whole project by building your own multi-year spreadsheet and putting
in your own best estimates of future energy costs, future power production of
the system, future interest rates, and future expenses of the system.  Drag it
out for as many years as you wish!

Vaughn



This Thread
Bookmark this thread:
 
 
 
 
 
 
  •  
  • Subject
  • Author
  • Date
please rate this thread