The current issue of home power magazine directly answers this ...
www.home-power.com

It is a myth (your understanding) , panels recoup there cost in about 2-3
years and will last much longer than 25 years. The 25 years , is the
manufactures warranty for 80% power generation .... The panels will last
until they suffer physically damage, the silicon will deliver power well
past our or our children's life times ...


"mike" wrote in message ...
I once read that it takes more energy to make, deliver, install a solar
panel than the total energy you get out of it over it's 20 year
lifetime. If that's true, (small scale PV) solar makes little sense
from an environmental standpoint.

mike

In article , "Joel Kolstad"
writes:

mike wrote:
I once read that it takes more energy to make, deliver, install a solar
panel than the total energy you get out of it over it's 20 year
lifetime. If that's true, (small scale PV) solar makes little sense
from an environmental standpoint.

My understanding is that improvements in the efficiency of the panels has no
longer made that true... although of course to some degree it depends on
where you end up installing the panels!

An easy way to determine whether or not the statement could be true is to
see whether or not the cost of the energy produced by the panel over its
life -- using regular market rates -- exceeds its cost. If so, obviously
the panel must be producing more energy than was requried to build it, since
all the labor and materials the manufacturer put into the panel weren't
free!

Actually, solar panels DO - under circumstances, but that seems
beside the point in this particular thread. We all get a migration
from the original thread question to automobile economy (!) and a
lot of polarized opinions. :-)

It seems that the higher the polarization level, the more they
become like electrolytic capacitors. Put them in the wrong way
and they blow up...

The original thread question (maybe) was about using solar
cells for battery charging. In that case there needs to be
identification with two major application areas:

1. The characteristics necessary to charge a particular battery.

2. The range of input voltage and current sufficient to operate
the charging circuit as obtained from solar cells.

Nobody seems to have addressed item (1) which would seem
to drive the whole task. Item (2) could have been satisfied with
actual measurements in a 48-hour time period, one day to set
it up, a second day to take the measurements, noting time of
day, cloud cover, etc.

Please excuse me for thinking linearly... :-)

Len Anderson
retired (from regular hours) electronic engineer person

In article , "Joel Kolstad"
writes:

mike wrote:
I once read that it takes more energy to make, deliver, install a solar
panel than the total energy you get out of it over it's 20 year
lifetime. If that's true, (small scale PV) solar makes little sense
from an environmental standpoint.

My understanding is that improvements in the efficiency of the panels has no
longer made that true... although of course to some degree it depends on
where you end up installing the panels!

An easy way to determine whether or not the statement could be true is to
see whether or not the cost of the energy produced by the panel over its
life -- using regular market rates -- exceeds its cost. If so, obviously
the panel must be producing more energy than was requried to build it, since
all the labor and materials the manufacturer put into the panel weren't
free!

Actually, solar panels DO - under circumstances, but that seems
beside the point in this particular thread. We all get a migration
from the original thread question to automobile economy (!) and a
lot of polarized opinions. :-)

It seems that the higher the polarization level, the more they
become like electrolytic capacitors. Put them in the wrong way
and they blow up...

The original thread question (maybe) was about using solar
cells for battery charging. In that case there needs to be
identification with two major application areas:

1. The characteristics necessary to charge a particular battery.

2. The range of input voltage and current sufficient to operate
the charging circuit as obtained from solar cells.

Nobody seems to have addressed item (1) which would seem
to drive the whole task. Item (2) could have been satisfied with
actual measurements in a 48-hour time period, one day to set
it up, a second day to take the measurements, noting time of
day, cloud cover, etc.

Please excuse me for thinking linearly... :-)

Len Anderson
retired (from regular hours) electronic engineer person

"Solar Guppy" wrote:
The current issue of home power magazine directly answers this ...
www.home-power.com

That's http://www.homepower.com/ (the other one is a WWWeb interface
to one of these newsgroups.

--
William Smith
ComputerSmiths Consulting, Inc. www.compusmiths.com

"Solar Guppy" wrote:
The current issue of home power magazine directly answers this ...
www.home-power.com

That's http://www.homepower.com/ (the other one is a WWWeb interface
to one of these newsgroups.

--
William Smith
ComputerSmiths Consulting, Inc. www.compusmiths.com

On a sunny day (Thu, 15 Apr 2004 05:57:18 GMT) it happened
wrote in :
A guy in Florida quoted 48 years pay back time. I ran
the numbers for my home - over 40 years, and I pay 13
cents per kwh. A 2 kW system costs $15000. Assuming
an average of 8 hours per day of 2kW per hour, that
solar system would give me 16 kWh. I pay 16*.13 or
$2.08 for 16 kWh. Works out to 19+ years for payback,
if you don't count on mortgage payments for the system.
Add that in, and the cost of a $15000 system is
much worse - over 30,000 in a 25 year, 7% mortgage.
You have to take into account that the cost of a kWh from
the grid in 25 years will be a LOT higher too, if there
still is a grid during and after WW3 that is.
JP

On a sunny day (Thu, 15 Apr 2004 05:57:18 GMT) it happened
wrote in :
A guy in Florida quoted 48 years pay back time. I ran
the numbers for my home - over 40 years, and I pay 13
cents per kwh. A 2 kW system costs $15000. Assuming
an average of 8 hours per day of 2kW per hour, that
solar system would give me 16 kWh. I pay 16*.13 or
$2.08 for 16 kWh. Works out to 19+ years for payback,
if you don't count on mortgage payments for the system.
Add that in, and the cost of a $15000 system is
much worse - over 30,000 in a 25 year, 7% mortgage.
You have to take into account that the cost of a kWh from
the grid in 25 years will be a LOT higher too, if there
still is a grid during and after WW3 that is.
JP

"Jan Panteltje" wrote in message
...
On a sunny day (Thu, 15 Apr 2004 05:57:18 GMT) it happened
wrote in :
A guy in Florida quoted 48 years pay back time. I ran
the numbers for my home - over 40 years, and I pay 13
cents per kwh. A 2 kW system costs $15000. Assuming
an average of 8 hours per day of 2kW per hour, that
solar system would give me 16 kWh. I pay 16*.13 or
$2.08 for 16 kWh. Works out to 19+ years for payback,
if you don't count on mortgage payments for the system.
Add that in, and the cost of a $15000 system is
much worse - over 30,000 in a 25 year, 7% mortgage.
You have to take into account that the cost of a kWh from
the grid in 25 years will be a LOT higher too, if there
still is a grid during and after WW3 that is.
JP

I would say that so far during WW# there is still a grid.

"Jan Panteltje" wrote in message
...
On a sunny day (Thu, 15 Apr 2004 05:57:18 GMT) it happened
wrote in :
A guy in Florida quoted 48 years pay back time. I ran
the numbers for my home - over 40 years, and I pay 13
cents per kwh. A 2 kW system costs $15000. Assuming
an average of 8 hours per day of 2kW per hour, that
solar system would give me 16 kWh. I pay 16*.13 or
$2.08 for 16 kWh. Works out to 19+ years for payback,
if you don't count on mortgage payments for the system.
Add that in, and the cost of a $15000 system is
much worse - over 30,000 in a 25 year, 7% mortgage.
You have to take into account that the cost of a kWh from
the grid in 25 years will be a LOT higher too, if there
still is a grid during and after WW3 that is.
JP

I would say that so far during WW# there is still a grid.

"Watson A.Name "Watt Sun - the Dark Remover"" wrote
in message ...
Charles W. Johnson Jr. wrote:

[snip]

While I'm all for using more renewable resources, and especially
ones that are environmentally friendly, it doesn't make sense to
cause yourself financial pain doing so. It makes sense to buy the
must fuel efficient vehicle that fits your needs but not to overspend
simply because it's a little better on the gas mileage.

It's not a "little" better, it more than double - 50+ MPG compared to
25!

[snip]

Surprisingly enough some SUV owners actually need the SUV at the time of
purchase, I personally drove through snow 70cm deep on a regular basis
prior
to my recent job change. Just because the people in southern California
don't need it doesn't mean no one does.

Charles

Surprisingly enough, many of those people who bought a big Ford
Expedition or GM Yukon could have got by with a lot smaller, and hence a
lot more economical SUV. ALso, there are vans, too, with a much better
gas mileage. Surprisingly enough, it's not about whether or not it's a
SUV or a truck or whatever, it's whether or not it's a gas guzzler.

A van with 4X4 or allwheel drive and ground clearance is an SUV.
Gas mileage becomes secondary if every time you try to move you get stuck.
The small SUV hold a family of 5 uncomfortably the larger hold a family of
seven, mom, dad, grandma and grandpa + 2 or more kids comfortably plus will
pull that 30'+ mobile home they camp in. Again not everyone lives in
Southern California where you can't do anything fun least you violate some
environmentalists dream.

Personally I bought the smallest vehicle I felt could do the job I needed it
to. That turned out to be a V6 that get about 25mpg highway.

Charles