permaculture

["Lawrence F. London, Jr." <lfl@intrex.net>]

Subject: RE: [permaculture] Solar Electric Confusion
From: "Harold Waldock" <haroldw@alternatives.com>
Date: Mon, 24 May 2004 14:48:29 -0700
To: "permaculture" <permaculture@lists.ibiblio.org>

I'm happy there is comment about the central Permaculture design question -
energy design. It is not discussed enough on this list.

David Holmgren's calculations on emergy were based on old data and old solar
panel construction techniques.  Classic solar panels are made with electric
furnace that purifies silicon, doped, sliced and laminated.  The newer
amorphous silicon by Unisolar is 9 layers more or less painted or stuck on -
a completely different technique.  They claim a 2-4 year energy payback.
Odum's technique which Holmgren uses may be much more rigorous though.  The
mounting systems made from aluminium, the inverter and balance of system
greatly reduces the net energy gain.  Unisolar's 3 wavelength capturing
panels capture up to 2x more power over a year than conventional silicon
panels in published field tests (not peer reviewed) because of a number of
features such as low light efficiency, reduced temperature effects, partial
shading efficiency and others.  This is where the very low numbers are
coming from.  Unisolar is about to complete a 30mw/year plant. However, they
appear to be finding difficulties at this time while their 5 mw plant is
running 3 shifts. The possible drawback is that Unisolar panels may degrade
efficiency faster over the long run than crystalline silicon panels although
no field evidence of this has been presented that show production to be less
than rated. Unisolar panels take more space and operate at lower area
efficiencies - made up for by their price/area.  For the power produced they
are the cheapest by 15%-20% in one envelope calculation I did and can
produce 2 times more power than conventional panels for rated capacity.  The
power or efficiency rating used by the solar panel industry is like meghertz
differences between Intel's Pentium and Apple's PowerPC processors.  Higher
numbers do not mean faster end user computations.  The problem is that it is
hard to come up with a widely used and known standard that will give good
comparable results in consumer applications.

Comparing emergy calculations between emergy calculation standards cannot
produce useful results.  Odum's ideas are a bit complex and philosophical so
his standards are not used much although they have much better groundings is
the theoretical issue of embodied energy.  Not all embodied energy
calculations are the same. Holmgren is signalling that there is rich
academic and eventually real world discovery possible in the thinking and
application of Odum's ideas.

Solar panels bear some watching, though.  There are some made with large
quantities Cadmium, a dangerous heavy metal, others with Arsenic. I believe
that in 10 years they will be much cheaper and lower emergy too perhaps then
they will be a good investment from the Permaculture perspective.  For many
areas of NA on the grid they do not represent a valuable addition to a
household from a short term financial point of view with out the subsidies
of other taxpayers.  Bill Mollison's system errors included one about not
doing proper accounting.

I don't believe that Bill Mollison ever intended Permaculture to be
ideologically pure or extreme.  I've a saying that I'm using often: "If it
is not transitional it is not Permaculture."  The reason is that if we swear
off solar panels then many people won't have transitional systems and the
movement towards a permanent culture will be halted for most.  More often
than not, the extreme ideologies never get implemented because they can be
seen as unreasonable.  While it is reasonable to want the straightest line
so as to arrive at the final destination as soon as possible, in real life,
all prudential (rather than moral) matters require transitions and less than
direct methods to achieve the goal.  Therefore, solar panels, even now, make
for good transitional tools in the right places.  Just because solar panels
may not have very good energy paybacks does not mean it can be argued that
they can't be part of a good permaculture design.

I do not accept Holgren's rather some times end-of-the-world tone as I
believe we can hope reasonably.  We cannot get people to change their ways
with out offering hope other wise people will prefer to drive SUVs while
saying their mantra of "Let's eat, drink and be merry, for tomorrow we will
die. (and run out of oil)"  Our job as designers is to provide reasonable
hope with our reasonable transitional designs that people will pay for
because they provide great value and cost savings.

The evidence I've seen suggest the energy payback on solar is quite
reasonable.


Harold Waldock
haroldw@alternatives.com
Cell 604 763 6984

-----Original Message-----
From: permaculture-bounces@lists.ibiblio.org
[mailto:permaculture-bounces@lists.ibiblio.org]On Behalf Of jeff
Sent: May 14, 2004 8:02 AM
To: permaculture
Subject: [permaculture] Solar Electric Confusion



Holgrem recently wrote about Solar electricity...