[GreenYes] using solar electricity and solar hot water

[Linda Christopher <lrecycle@garbage.org>]

Solar electric panels w/a battery backup produce 12V direct current 
which is unsuitable for running high amperage power tools.  Instead 
you would need to 1) buy a <lot> of panels (combining solar and wind 
is ideal a small scale electric system), 2) then have an inverter 
that converts the 12v Direct current to 120 Alternating Current. 
Expensive-even assuming this is not a commercial project.  Your draw 
(amperage) will be high you so will still need to be connected to the 
grid so you can draw down the additional energy when you need it, 
then sell energy back to the grid when you are producing more than 
you are using.  The advantage of this system is you don't need a 
battery bank for storage (which is a pain) . You are using the grid 
as storage as well as back-up. (Besides you need to use excess 
generation to run that meter backwards to justify the expense).

(You might want to consider starting with solar hot water instead of 
solar electricity. It is simple, low-temperature technology and may 
have a better payback. )

Back to solar electricity: I'm a fan of keeping it simple. That is 
use a combo small scale wind/solar/hydro set-up w/ a battery storage 
and using 12V appliances when appropriate.  (although some would 
argue the batteries are not so simple).

So what does appropriate mean?  There are many appliances which are 
well suited to operating at 12V DC.  Just think of how many are 
designed for RVs.  Lights are a good example.  Other appliances can 
be converted.  Even computers.

High amperage appliances (microwaves, power tools, even blow-dryers!) 
are unsafe to operate on direct current- among other system design 
problems. Since you have so many of those items, it's not too 
practical to leave the grid.  That means going with the inverter, 
then you don't have a dual AC/DC system and a bunch of batteries to 
keep around.

Just a hint: The first step to retrofitting a conventional house for 
solar electric is to buy ultra energy-efficient appliances- not the 
refrigerators you buy at Sears. You can start with that.
-- 
Linda Christopher,  Program Director
The Materials for the Future Foundation
(415) 561-6530 x15
www.materials4future.org