[SGVLUG] Off-topic - home guerrilla solar systems

[Michael Proctor-Smith]

On 2/24/07, David Lawyer <dave at lafn.org> wrote:
> On Fri, Feb 23, 2007 at 08:07:00AM -0800, Don Gibbs wrote:
> > While the group entertains this off-topic thread ...
> >
> > I've wondered about the long-term benefit of PV (photovoltaic)
> > systems.  I've done a some searching but have not seen any decent
> > analysis evaluating the overall energy efficiency  of such systems.
> > For instance, for a non-steerable, residential system capable of
> > delivering 1kW peak (noon, mid-summer, surface normal to sun) in the
> > LA area and tied to the neighborhood utility, how much total energy
> > was required to build and install it and how much total energy will
> > it deliver over a ten year period?  I suspect the payback is pretty
> > good.  But my gut judgements have proven wrong before.
>
> If it costs less for electricity this way, then it likely will use
> less energy.  All energy (including labor energy) get added to costs
> so this is about the best criteria we have for estimating energy
> content.  I've read that PV will cost more for electricity so if
> that's the case then it's a loser.  Another unknown is how long the PV
> installation will last.  You also need to include the cost of
> batteries.  The cost method of estimation of energy content has been
> widely used for decades.

You do not have to include the cost of batteries unless you want a
totally off the grid solar electric system. You install the solar
system and then when your solar panels are producing  energy you can
actually spin your power meter backwards(if they produce more power
then you are using) and get credit for the energy that you are adding
back into the power grid.

> Here's an important paper on PV economics from profs. at the Naval
> Postgraduate School at Monterey, CA.  They seem to agree with me and
> conversely.
> http://www.nps.navy.mil/drmi/WorkingPapers/DRMI%20Working%20Paper%2006-02.pdf
>
>                         David Lawyer
>