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What are some payback times for systems currently installed? - Page 5

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Posted by Ron Rosenfeld on November 15, 2011, 12:06 pm
 


I think you are absolutely correct concerning the financial viability of
unsubsidized, grid-connected PV systems.  

But a number of locales do have subsidies which make PV competitive with mains
power (and one could get into a long and irrelevant argument about subsidization
of mains power and its sources, but I digress).

For your system,  you could also compare your actual output with your predicted
output.  The predicted output depends on "solar insolation" which is the average
number of "full-sun hours" at your locale for a given time frame.  For example
PVWatts suggests that in the winter, you might average 3 "effective-sun-hours"
per day.  That means you should expect no more than (45 x 3) watts output from
your setup, on average, per winter day.  Many factors will derate this further,
however.

I have an off-grid system, and averaging data over about six years, I draw some
interesting conclusions.  Comparing with PVWatts, an NREL tool for such
modeling, and taking into account orientation and location, I get about 40-50%
of the predicted output for my size system.  However, using a more sophisticated
tool (embodied in the HOMER program), the predictions for output are about 85%
of my measurements.  I suspect the PVWatts database does not take into account
my coastal location, which has increased fog.  And the HOMER numbers may be a
bit low as I get significant energy from a wind turbine (so the PV array will
not be generating measureable power when the batteries are full).

Again, so far as the economics, the power company wanted $0K to extend the grid
to my house.  My system's payback was instantaneous.  Had grid extension costs
been less, however, they payback would not have been there.

Posted by stevey on November 15, 2011, 3:50 pm
 
Hi Folks,

I'm glad to see you all engaged on this topic.
As an energy engineering profession, and founder of Wattminder,
investing in solar power
is a given--Sun's energy is FREE and forever.  I like to introduce
PVmonitor.net, our 5-year old
PV performance benchmark on demand;  and its successor PVwizard.com.
Both offer FREE
benchmark calculator service on-demand and instant display to help you
check up on your site.

In the past few months, Wattminder has been working on our second
generation,
on-demand analytics service platform for solar power sites anywhere in
the world.

It is in all-free beta trial for a month, in which we hope to gather
input
from users like yourselves so that we can modify and improve on it.
The basic benchmark service has been revamped with refinements like
aging
consideration, tracking, irridiance correction for air-mass; will
always be free.

While more advanced services added like Performance Check and
Degradation
Assessment will become fee services after the beta trial.

Please visit www.pvwizard.com , and give it honest and brutal
critique.
We won't be offended by your comment. For a brief introduction, see--
https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid xuyQoc-vUJ-MzRlNmM5ZjYtNjQ2My00YjlkLWIzOTgtOTk5YmZhOWYxZGRj&hl=en_US
Thanks and looking forward to hearing from you.
May the Sun always warm your face and your panels!

Posted by Mho on November 16, 2011, 4:08 am
 Great!  A sales spammer.

You are one of the types that has been lying to the public for years. The
bias has been exposed by most experienced suckers that purchased, in the
past. Without subsidies PV has been a dead loss financially.

With or without financial subsidies, PV systems have been a dead loss,
ecology wise. The pollution created in manufacturing and maintaining a
system has always outweighed the pollution generated by current electrical
generation systems, creating that same energy.

Where grid energy is not available cheaply, PV is a necessity, usually.

---------
"stevey"  wrote in message

Hi Folks,

I'm glad to see you all engaged on this topic.
As an energy engineering profession, and founder of Wattminder,
investing in solar power
is a given--Sun's energy is FREE and forever.  I like to introduce
PVmonitor.net, our 5-year old
PV performance benchmark on demand;  and its successor PVwizard.com.
Both offer FREE
benchmark calculator service on-demand and instant display to help you
check up on your site.

In the past few months, Wattminder has been working on our second
generation,
on-demand analytics service platform for solar power sites anywhere in
the world.

It is in all-free beta trial for a month, in which we hope to gather
input
from users like yourselves so that we can modify and improve on it.
The basic benchmark service has been revamped with refinements like
aging
consideration, tracking, irridiance correction for air-mass; will
always be free.

While more advanced services added like Performance Check and
Degradation
Assessment will become fee services after the beta trial.

Please visit www.pvwizard.com , and give it honest and brutal
critique.
We won't be offended by your comment. For a brief introduction, see--
https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid xuyQoc-vUJ-MzRlNmM5ZjYtNjQ2My00YjlkLWIzOTgtOTk5YmZhOWYxZGRj&hl=en_US
Thanks and looking forward to hearing from you.
May the Sun always warm your face and your panels!


Posted by argusy on November 16, 2011, 8:46 am
 On 16/11/11 2:38 PM, Mho wrote:

always

<snip>

no point in replaying the sales pitch, Mho <grin>

Lurkers!!

Always waiting in the background, just ready to pounce.
I've written my own power/pv monitor program, using a well-known
monitor/transmitter that has been re-branded in several countries.

I couldn't find a cheap enough program that recorded three phases, and presented
enough graphs on the data I wanted, so this old noggin just had to sit down with
a book on serial comms (which I really hadn't looked at much)
and plenty of searching via google for a decent (ie cheap) chart/graph for VB6

IT took me a lot of weekends, but I've now got an old Toshiba laptop (Win 2K)
running 24/7 with my program. Now I'll just have to buy a single PV panel, a
cheap DC-DC inverter and a big enough battery to last all night just to keep it
off the solar system.

Oh well, I might as well put it on a pole with a sun-tracker, and get the most I
can out of it.

Graham

Posted by Mho on November 16, 2011, 6:06 pm
 Man! The hours I have spent professionally and personally writing serial
port twiddling routines to poll equipment! I would be ashamed to admit it,
sometimes, well, to the management, anyway...LOL

I tried to get any protocols out of my Co-gen / inverter / charger / MPPT
unit manufacturer but they clam up. One day **SIGH** I will connect the old
RS-485 adapter up and rip off the comm protocol and write my own stuff also.
Their monitor programme sucks. VB 6 sounds great... never could get any
VB.net stuff working and haven't had the time. X-10 software I wrote needs
work and polish too then I have a few RTU units I need to make talk to
control some house stuff...drive is fading though, too many other projects.

Sounds like a parallel world over there!

Sorry about the replay. I usually snip or obliterate the stuff when whining
about something.

--------------
no point in replaying the sales pitch, Mho <grin>

Lurkers!!

Always waiting in the background, just ready to pounce.
I've written my own power/pv monitor program, using a well-known
monitor/transmitter that has been re-branded in several countries.

I couldn't find a cheap enough program that recorded three phases, and
presented
enough graphs on the data I wanted, so this old noggin just had to sit down
with
a book on serial comms (which I really hadn't looked at much)
and plenty of searching via google for a decent (ie cheap) chart/graph for
VB6

IT took me a lot of weekends, but I've now got an old Toshiba laptop (Win
2K)
running 24/7 with my program. Now I'll just have to buy a single PV panel, a
cheap DC-DC inverter and a big enough battery to last all night just to keep
it
off the solar system.

Oh well, I might as well put it on a pole with a sun-tracker, and get the
most I
can out of it.

Graham


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