[Pil-pc-oceania] better than sliver technology (PV)?

[Meadows, Joel]

Dear Petra,
Your 11 kWh/day is indeed below average (particularly for a household
with 5 people - am I right? - and a business). The average Australian
household uses between 16 - 18 kWh/day depending on what figures you
use, but the average household size is just over 2 people. Some recent
work I have been doing in inner city Melbourne has shown households in
one area averaging 19 kWh/day, and this in area with 1.8
people/household. 

The other big factor to consider is reticulated (or bottled) gas use. If
you have gas you are deferring quite a bit of electricity use (heating,
hot water [the big ones in cooler areas] and cooking) on to gas, so
gassed areas should be below average in electricity use.

We have spent quite a bit of time improving the efficiency of our
households electricity use. By this I don't just mean the technical
efficiency of the appliances we use (i.e. compact fluoros over
incandescent), but the efficiency of the way we install things (i.e.
lights hung into rooms for bounced and reflected light rather than
recessed into ceilings) and the efficiency of usage (i.e. Not leaving
lights on when there is no one in the room). We have managed to get our
usage down to about 2.5 kWh/day, though absolute figures have become
hard to work out now that we are generating power on-site (PVs) through
the one meter.

Regarding PV 'efficiency' there is quite a bit of rubbish to wade
through (in fact I think all 'efficiencies' should be seriously analysed
before accepted). Technical efficiency for PVs is the power generated by
the panel for the area it takes up. So highly efficient panels are just
smaller than less efficient ones, not necessarily cheaper, or with a
lower embodied energy (generally the higher the efficiency the more
complex the construction), or longer lasting, or even more powerful in
real world situations. 

Amorphous panels (those black/grey ones) have always been less efficient
(i.e. bigger) than a monocrystaline (those bluie ones). But many claim
they use less energy to make, work better in part shade as well as
better in high temperatures, so might well have a greater overall power
output than the more 'efficient' options. So as for which PV panel to
choose I'd be looking for made in Australia (which limits you to BP
panels from the Sydney plant, and Origin 'sliver' panels from SA [are
they actually available yet? Are they really any cheaper than the
competition, or like all the other 'price breakthroughs' in PV history
was that just a bit of spin?].

According to the Going Solar website at you current usage (11 kWh/day)
you will be needing  a 2.55 kilowatt array (I think this is a bit of an
underestimation) to generate your annual electricity, and you'd be
looking at $28,600 less rebates. I can think of a good deal more you
could do with that kind of money that would have a much greater impact
on greenhouse emissions.

According to the ACF Consumption atlas
(http://www.acfonline.org.au/custom_atlas/index.html - YOU WILL NEED
FLASH TO VIEW THIS AS IT IS QUITE FLASHY) household electricity use only
accounts for 20% of our total household greenhouse emissions, transport
only 10.5%, where as food is 28.3% and goods and services 29.4% with
construction making up the other 11.8% (this calculator does not factor
in government services, which when included on a per citizen basis can
be the largest single item on the greenhouse table). So those who claim
carbon neutrality by purchasing greenpower and paying greenfleet are
only dealing with 30% of their emissions, and then perhaps not even
dealing with that.

Happy to chat more off-list if you want some system sizing and household
efficiency advise (and I'm still happy to have you over for a visit,
lets try again this week).

Cheers,

Joel Meadows


-----Original Message-----
From: pil-pc-oceania-bounces at lists.permacultureinternational.org
[mailto:pil-pc-oceania-bounces at lists.permacultureinternational.org] On
Behalf Of petra.kahle at haztech.com.au
Sent: Sunday, 5 August 2007 11:08 AM
To: permacultue discussion list
Subject: [Pil-pc-oceania] better than sliver technology (PV)?

Hi All,
in my search for sliver technology photo voltaic cells (which are said
to be very efficient) I found concentrating pv cells -
www.greenandgoldenergy.com.au.
Greens friend Alistair McCaskill reckons they are better than sliver. I
can't judge that, can you?

We use under 4000kWh per year in electricity. I think that is lower than
average for a 4 person household, especially since we run a business
from here too. But we still have waste in there. How much do you use?

My partner Jeff is now starting to think about installing a 1Kw pv
arrangement since he heard that if you make good arrangments with the
power companies you might get the cost back in one or two years!

Cheers, Petra.


PS Chisholm Greens candidate Alistair McCaskill is now looking for
letterboxers and organisers for letterboxers.
Phone:  03 9890 7126
Mobile:  0411 400 908
Fax:      03 8640 0739
website: www.alistairmccaskill.org
"Alistair McCaskill" <chisholm at greens.org.au> or contact me.
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