The cost of being on-line

[Martin Naef]

Hi Denis

On 26.06.2011 7:50, diode wrote:
> Right now, the only ENR not at its full potential technically is PV
> solar. We can achieve about 19% efficiency at best. 24% in the
> laboratory. The guy who finds out how to make a 80-90% efficient PV
> is RICH.

That would be a dream indeed. Though the high efficiency must still be 
affordable...

> PV lasts about 20-30 years, now are recyclable (or soon will be), and
> needs only cleaning…

Actually, PV generally lasts significantly longer. 20 to 30 years is 
what the manufacturer guarantees, and it usually means that after that 
time it still generated something like 80%+ of peak power. Recent 
figures I heard assume that PV panels can easily be run for 50 years and 
still reach something like 70%. The inverter needed to feed the power 
into the grid won't last that long, though - but that can be replaced.

> Thermic solar is very efficient (in the 90% figure) and you can even
> use it in Scandinavia. You can even make electricity from it (as the
> EU is financing the plants in Spain and North Africa).

Thermic solar only works with direct sunlight. That's all right for hot 
water, but not very efficient for electricity production given the 
weather in the north. That's why they are built in Spain, southern Italy 
and Africa indeed. But don't forget that this energy must be 
transported. That's not a technology problem, but a political one.

> The best Nuclear power plant is 32% efficient on secondary energy
> (once you have left the 98% of the fuel not used) and it's not going
> to get better anytime soon. 3rd gen plants (EPR) are not much

Sure, but who cares? Nuclear isn't limited by space, and I don't think 
the actual fuel is the big cost driver.

But all the efficiency figures aside, the big problem with those 
alternative sources is controllability - or rather the lack of. Unless 
we solve the storage problem and build up rather massive transmission 
capacity, they can never be the sole solution. Anybody who wants to shut 
down nuclear and coal plants today or within the next five years is 
chasing a dream.

Martin