[aprssig] Solar, then vs now

Rich Mulvey aprs at mulveyfamily.com
Mon May 23 15:15:57 EDT 2011


I'll dig up the latest values, but even so, I sincerely doubt it would
make much difference.  In my particular case, our yard and house is
completely shaded.  Summertime electricity costs are something like
$40/month, as we pretty much never need A/C.  In the wintertime, when
the leaves are down, the roof is covered with snow from at least
December to March, and usually from November to April.  Natural gas
costs dominate the utility bills by far during that period.  And as I
said, there's no way I'm cleaning off any solar panels on a daily
basis.  :-)



On Mon, May 23, 2011 at 1:59 PM, Bob Bruninga <bruninga at usna.edu> wrote:
>> I ran some calculations a couple years ago for my house
>> in upstate NY.... It would never have even come close
>> to breaking even during my expected lifespan.
>
> Which is the point of this recent discussion!  We were so wrong back then!
>
> Depending on what you mean by "a couple of years" and what you *assumed*,
> the difference between then and now could be 2 to 40 times more cost
> effective today than it was "a couple of years ago"...
>
> I had the same conclusions back before the 1st week in August 2009 when for
> the first time in years, I actually looked at the new math.  I was shocked
> to see that I was *so wrong* by a factor of over 30 to 1.  Here is why I was
> so wrong:  I had overlooked these recent factors:
>
> 1) The cost of electricity in Maryland went up 50% recently (X1.5)
> 2) The cost of solar has dropped in half in the last few years (x2)
> 3) I overlooked the 50% government credits (x2)
> 4) I was using the idea of battery storage (x3)*
> 5) I overlooked the annual SREC payments (x2)
>
> Multiply all those factors 1.5 X 2 X 2 X 3 X 2 = 36.  I was wrong by a
> factor of 36 to 1!  That is why I sound so born-again.  I was so wrong with
> my old thinking on solar and want to share my conversion...
>
>> The only solar system that would have made even a
>> moderate amount of sense was solar-assisted water heating.
>> And even that would have been iffy.
>
> Do the calculations again (now), and make the right assumptions and you will
> be absolutely amazed at the results (if your state is progressive)...
>
> Bob, WB4APR
>
> * Note:  If one does not understand why the useful energy from an off-grid
> battery storage solar system is only 1/3rd that of a grid-tie system, please
> see www.aprs.org/off-grid-maybe.html
>
>
>
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-- 
rich at mulveyfamily.com




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