It is highly unlikely that a solar panel will have such a short lifespan.
Solar cells are
basically semiconductors, and you can pick up a transistor radio today that
was manufactured with the early generation of transistors used in the 60's
and
it will still play (if the batteries haven't leaked all over the inside)
And the
semiconductor area in a transistor is hundreds if not thousands of times
smaller
than a solar cell.  Semiconductors degrade from ion shift within the
semiconductor
and from overloads, all very important when the conductors are microscopic,
but not much of a concern when the conductive areas are huge as in a solar
cell.

I wouldn' t be surprised a bit if a solar cell lifespan exceeded a century,
and I
suspect it is much, much longer, if the high energy light (ie: ultraviolet)
that
doesen't contribute to power generation is filtered from the cell.  See the
following
for current research on what destroys solar cells:

http://www.eurekalert.org/pub_releases/2005-06/ou-nsw061705.php

Ted

They have a gaurantee of efficiency of 25 years. Their life has never been
determined yet.

This is not true. Current PV panels generate their construction energy
in 3 to 6 years. They have a life well over 25 years. They are a viable
solution for off-grid situations, and will be economically viable for
on-grid apps as fossil fuel costs climb higher.

Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html

snip

Question

I have been informed? that current solar cells consume more energy in their
fabrication than they will generate in their lifetime.

Is this true?  Please comment
thanx

I am impressed.  Where do you live.  How would this system perform at
latitude 51degrees N.?  In the winter?

thanx
snip

This is open to much argument, but there are too many profit oriented
concerns that seem to be investing heavily in new facility startups for
the production of panels at today's pricing, for the panel manufacturer's
costs to be any where close to the naysayer's guesses.

The efficiency of today's DC to AC grid based inverters is very good,
typically above 92% per the State of California's very conservative
testing procedure results used to qualify for rebates. (Results on web)

I admit that the 12, 24, and even the 48 VDC systems that are commonly
used in OFF GRID battery PV solar systems usually use large diameter
conductors between the panels and the battery controllers / inverters.

However, in ON GRID systems (like my own) that do NOT use ANY batteries,
Much higher DC voltages are usually used. My own system right now at
5:00 PM 8/27/05 is producing 359 VDC power from the panels on a day
when the temperature was 103.1 degrees F.  

I use the SMA Sunny Boy 2500U inverters (4).  By the way, I produce
enough power that I have averaged getting an credit of ($2.49) for
every day since the 13th of June from my electric utility.

None, its all on my out of food production roof. It is also much more
efficient, because there aren't any line losses in transmission to
my house for what I do use, nor, is much lost in transmission to my
immediate neighbors who receive my surplus production via the grid.

Bob Gardner

I can't argue this number, I've see it before, but I don't see
hydrogen as even part of the "vehicular fuel" solution, it has NO existing
distribution, storage, or developed vehicular power plant.

Hybrid Bio-diesel vehicles using the principles proven by the Toyota, Honda
and Ford's PRODUCTION hybrid gasoline vehicles in conjunction with
urban solar PV power could work very well as vehicle fuel sources.

These Bio-diesel fuels could utilize existing infrastructure external
to the vehicle, and perhaps could be retrofitted.  Note: the railroads
are using hybrid diesel locomotives in some of the worst polluted cities
TODAY, to improve the diesels efficiencies and for pollution reduction.

We need some way to use up our existing energy supplies though.

I have to chuckle when I see solar recommended as the final solution. No one
seems to consider the amount of energy it would take to manufacture the
panels, to convert the DC to AC, to make the large-diameter/low resistance
conductors necessary to carry such small voltages, and finally, the amount
of land taken out of production because it is in constant shade.

Bob Gardner

The problem with burning hydrogen is that solar panels can't make enough of
it. To replace today's vehicular use of oil, we'd need 230,000 tons of
hydrogen daily.  Solar cells to make that much hydrogen would cover about
20,000 square kilometers.  To get this much power -- 400 gigawatts daily --  
without carbon emissions, the only cost-effective solution is nuclear
plants. And that has its own political and ecological consequences.  See
http://www.world-nuclear.org/opinion/grant.htm

Seth

I think you're mostly right for short term, but long term belongs to
hydrogen.
The problem with solar is storing the energy. Stick a solar panel in your
back yard that converts water to hydrogen, and you can store as much as you
want.

I would like to present to you the (near) future of transportation...

Diesel hybrid cars (full two-mode plug-in hybrids)
Diesel for motorcycles
Diesel (probably 2-stroke) engines for general aviation (including
rotorcraft)
Extensive use of bio-diesel

Hybrid cars (gasoline)are in production
Diesel hybrid trucks and busses are in production
Diesel motorcycles are / will be in production soon
Diesel aviation engines are in production...more are coming

Very soon we will see the first diesel hybrid passenger car in
production

Diesel for aviation or motorcycles...they have been around for some
time. Think of Junkers "Jumo" 205. Decades ago there were several
Diesel aircraft engines built by Guiberson, Packard, Rolls-Royce,
Clerget, Fiat and others. Royal Enfield (India) has had a diesel
motorcycle in production for some time. I believe it is now
discontinued.

Some diesel hybrid car prototypes...

GM's Ope Astra diesel hybrid
Citroen Berlingo diesel hybrid
VW Golf diesel hybrid (so I hear)

Some diesel aviation engine prototypes...

SMA Morane Renault MR 200 www.smaengines.com
Teledyne Continental Motors CSD-283 www.teledyne.com (Nasa GAP)
DeltaHawk V-4 www.deltahawkengines.com
Zoche 01A www.zoche.de
Diesel Air Ltd. DAIR-100 www.dair.co.uk

Some (gasoline) hybrid cars in production...

Toyota's Prius and Lexus
Ford's Escape Hybrid

Some diesel motorcycle prototypes...

Diesel Kawasaki M1030 M1 (KLR 650) F1 Engineering / Hayes Diversified
Technologies (HDT)

For third world countries a diesel motorcycle could be ideal. It is
probably very dependable and durable and relatively easy to fix. It
could be bi-fuel, meaning it could use diesel, Jet A, light heater oil
and most importantly... bio-diesel and even straight vegetable oil
(SVO). It could ne equipped with a small (max 200kg) 2-wheel trailer
and a power take-out (PTO). The PTO would mostly be for a generator
and/or (water) pump.

Picture this. In a third world country, a motorcycle travels 100km @
80kmh with 2 litres vegetable oil that they have made themselves. It
then pumps (with a pump attached at the PTO) from a deep dwell 150
litres of fresh water into a tank that's on the trailer, drives back
and delivers the fresh water to the families in the village. Later at
night, it runs to provide electricity (with a generator attached to the
PTO) for many houses in the village and to recharge the batteries. This
motorcycle and its accessories the families in the village have bought
together, with some help from some organisation like the UN.

Of note: Of course the best way to produce electricity in these often
sunny third world countries is solar panels!!