[mythtv-users] [Slightly OT] solar power for all our gadgets

Jeff Walther trag at io.com
Mon Mar 9 16:54:14 UTC 2009

> Date: Mon, 09 Mar 2009 07:53:10 -0700
> From: Yan Seiner <yan at seiner.com>

> Jeff Walther wrote:
>> Anyway, this topic kind of chaps me because I frequently hear the media
>> non-critically hyping how wonderful it is to have solar panels, and the
>> fact is that anyone who can do simple math (and doesn't live somewhere
>> with really expensive electricity) can see that they make no economic
>> sense whatsoever.
> Alas, the ability to do simple math and a PV analysis is sorely lacking
> in the US... Witness the current housing meltdown.
> I did the same analysis.   It costs about $10K/1KW for solar.  With
> state and federal subsidies, the break-even over 20 years is about
> $0.15/KWh, and the life of the equipment is 20 years.  This assumes no
> maintenance.

Was your $10K/1KW figure the nominal generating capacity or the actual
generating capacity?   It makes a difference of a factor of 2.5X - 3X.

See my paragraph in my original posting about getting 400 KWH per month
out of a 3000 watt installation.

They'll sell you a panel with a "capacity" of 1 KW but that's its capacity
under ideal conditions.   It might generate that in the desert, mounted on
a sun tracking platform.  On a residential rooftop, you'll get 100 - 133
KWH/month out of that 1KW panel.

That's the place where folks really fall down, and despite my snarky
comment about math skills, it's hard to blame the consumer.  Someone tells
them an installation is 3000 watts capacity, they think they'll get 3000
watts while the sun is shining.  They don't know enough engineering to
realize that ideal conditions do not apply most of the time.

I had to hunt far and wide before I found a solar panel installer who
actually admits what the customer can really expect to generate from a
given "capacity" of panels.

Unfortunately, this kind of deception and wishful thinking is driving
public policy.  Sigh.

Jeff Walther

More information about the mythtv-users mailing list