[LINK] A Clean Energy Revolution -- Now

[Michael Skeggs mike@bystander.net]

Yes, but the transmission loss over a few metres from a roof to the
meterbox is nominal.
DC strings of panels typically operate at 300v to 500v DC. Which isn't a
lot in terms of arc-ing.
The other advantages are accurate, to some extent.
In a lot of ways, it boils down to economics. If I am launching a space
satellite, efficiency is critical. If I am trying to contribute to a
suburban power bill, not so much. So paying more will deliver increased
efficiency, but is it justified?
As a broad and sweeping generalisation, silicon solar cells are just about
as good as they are going to get right now, and we won't see any further
step change price drops unless there is a so-far unknown technical
revolution. The panel manufacturers have captured just about every economy
of scale and optimisation of the production process.
The panels account for around half the cost of a residential PV system, and
retail about $1/watt in bulk.
The other half is the inverter, mounting frames and installation labour.
The labour cost is hard to trim, the frames are hard to make less
expensively, so that leaves the inverter as a point for further cost
savings.
To date, inverters have been big hunks of comparatively dumb electronics,
e.g:
http://synapsesolar.com/index_files/slides/Inside%20inverter.jpg

Splitting these off into small, micro inverters per panel exposes them to
the same benefits of micro-electronic production that has delivered massive
cost savings in consumer electronics over the past 30 years.

So I definitely agree micro inverters are great, but their cost will drop
like a stone over the next 5 years, so I wouldn't be paying a premium for
one today.
They do offer potential to make it trivial to expand today's DC string
installations by adding additional panels that connect directly to the
meter as a second stand alone installation.

Solar PV is considerably cheaper than grid power everywhere in Australia
right now. I'd urge any linkers who might be thinking solar power would be
good, but to hold off as the price will drop further to go ahead and act
now. If you wait longer, you are postponing savings and might find that
costs actually go up as government support programs are withdrawn.

Regards,
Michael Skeggs
(who is also on the board of www.bmrenew.org)



On 22 September 2013 22:59, Hamish Moffatt <hamish at cloud.net.au> wrote:

>
>
> Two fundamentals haven't changed though;
> 1. Transmission losses are proportional to current (P=I*I*R), and higher
> voltage means lower current (P=V*I, P is constant);
> 2. It's a lot easier (cheaper, more efficient) to step between voltages
> with AC than DC.
>
> Hamish
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