Thread: Grid can go 75% renewable

Originally Posted by JDNSW

Similarly, yes, solar efficiency does decrease with increase in temperature, but the effect is relatively minor, and more than compensated for by the longer periods of sunlight which accompany hot weahter and droughts.

Reality is that solar panels see temperatures of 50c and at that temperature, the loss is NOT minor but as much as 30% loss.

They also have a lifespan of only 25 years at best which amounts to a total REAL cost of at least 2.6 times the initial cost to equal the normal lifespan of a coal fired power station.

There is just too much b/s around how good solar panels are!

Originally Posted by drivesafe

Reality is that solar panels see temperatures of 50c and at that temperature, the loss is NOT minor but as much as 30% loss.

They also have a lifespan of only 25 years at best which amounts to a total REAL cost of at least 2.6 times the initial cost to equal the normal lifespan of a coal fired power station.

There is just too much b/s around how good solar panels are!

25 years after installation my original solar panels showed no measurable reduction in output. And in my experience, days with air temperatures up around the high forties were also among the days of best output, because they were long days of unobstructed sunshine.

These panels are no longer in use, the whole system having been replaced using panels with three times the output per panel.

While I have seen the life of panels quoted as 25 years, i have yet to see real evidence to support this. Although I have no doubt at all that some panels will have a limited life, there does not appear to be anything inherent in the technology that says this is necessarily the case.

The 25 year expected lifespan is what the solar industry quotes.

This I imagine would be based on what the total output capacity a solar would be at 25 years, not if the panel still worked.

I have no idea how they rate solar panels but I would expect it to be something like the way they rate lead acid batteries.

If a lead acid battery is no longer capable of supplying at least 80% of its original capacity, the industry recommends it be replaced.

It still works, but is down on capacity. So solar panels would probably have a similar rating.

In my experience, the output of solar panels doers not deteriorate significantly with age, unlike the example of lead acid batteries. The fundamental difference is that a battery operates using a reversible chemical reaction, which, in real life, is never exactly reversible, so that recharging the battery never restores it to exactly the original state. In the case of a lead acid battery this primarily takes the form of the creation of lead sulphate crystals that are much larger than in the original construction, and are either much less soluble, or damage the plate structure (or both).

In the case of a solar panel, there is no chemical reaction, the operation occurring at the subatomic level. There is no "cycle". The only reason for a limit to the life of the panel is deterioration of the construction materials due to exposure to the weather. This is very dependent on the design and the construction and on the climate to which it is exposed. These vary so much that the very conceopt of a specific "life" is ludicrous. And the industry has not really been in existence for long enough to have a real idea of how long the panels being put in service today will last. But we do know that a lot of the ones made 25 years ago are still producing close to their original output today. Note that some proportion of them do fail - due to manufacturing faults, or lightning or mechanical damage.

Solar panels do wear out.. 3 different ways.

LID - initial usually working first 1000 hours due to now being exposed to light

PID - more rare and often from voltage differential in the panel itself

ARD - age repeated and due to the composition of the panel degrading from the light & heat

A reduction of 20% can be expected for 1 & 3 combined.
2 can result in up to 30% losses.

Originally Posted by drivesafe

The 25 year expected lifespan is what the solar industry quotes.

This I imagine would be based on what the total output capacity a solar would be at 25 years, not if the panel still worked.

I have no idea how they rate solar panels but I would expect it to be something like the way they rate lead acid batteries.

If a lead acid battery is no longer capable of supplying at least 80% of its original capacity, the industry recommends it be replaced.

It still works, but is down on capacity. So solar panels would probably have a similar rating.

Yep, it's exactly the same with panels, degrade to 80% (from memory) at 25 years.

In my actual experience, not memory, less than 10% degradation in 25 years.

The Australian headline today." WA to import coal from NSW"
ROTFL.
Regards PhilipA