https://upload.wikimedia.org/wikipedia/commons/4/42/Efficien...
The conclusion of that chart seems to be : concentrated solar power (even on small scale) is unbeatable, and tops out (realistically) at ~40% efficiency.
So now we should probably work on very, very cheap lenses if we want to advance solar panels, and quick ways to make small, very cheap panels.
This cell is the blue dot "Kaneka".
Multijunction cells are very expensive to make. The reason the multijunction cells in that chart all have concentrators is that without them, the cost is ridiculously too much to even consider.
This particular cell is noteworthy because it is cheap enough that you can eschew the added cost and complexity of the concentrator and just use more cells and potentially still be cheaper.
That's the operative word here. And that is far from a run race with this particular technology, it is going to be close enough that it bears watching but not so good that it is a slam dunk winner.
You could use some of that energy to have tiny motors that track the sunlight.
This would net in more energy and less cost per square meter right?
- you only need one motor to aim a whole array of mirrors
if you're willing to make some exotic gears
- the lifespan of the cells will shorten measurably
- you will need to cool the cells if you don't want them
to die very quickly
- there will be a serious fire riskAt this point in time there are no cheap and easy solutions in sight to make the next 2 to 5% gain in efficiency in a cost effective manner.
But given enough time and effort I'm sure that that will happen, I expect the final cut-off to be somewhere around 25% net efficiency (solar incidence to electricity out of the system) for smaller installations and maybe up to 30% for much larger installations.
Will this require more complex installation than flat panels?
Will this require more lifetime maintenance than flat panels?
If the answer to either question is a yes, it doesn't matter how good your system is in any other measure, you will lose against simple flat panels in total cost per electricity produced for any small-scale installation.
Leakage current, which happens even in darkness, wastes power at a fixed rate per unit area. By concentrating sunlight, one can generate far more than this leakage rate making it insignificant.
More important than energy efficiency is price per unit energy. You could have an inefficient but cheap solar cell that's more economical than an expensive efficient one (eg. active tracker vs fixed - the less efficient option is usually more economical). Though when installation costs dominate, then you really do want smaller panels so you can spend fewer man-hours nailing them up.
It's impossible. That said, every type of solar panel works best with direct solar irradiance, what you can get from scatter off clouds and on overcast days is a pittance even in the best situations compared with direct light.
So this isn't nearly as big a step (yet) as it is made out to be, it may work out commercially but that is definitely not clear at this moment, and if it does work out commercially then it remains to be seen how much of that efficiency gain ends up reducing the per KWh installed cost of the panels. Any net gain of course is good.
I don't follow this argument. The median panels used in actual installations have increased in efficiency from about 16% to about 18% over the last 10 years (while the prices have more than halved).
First, the chart you link to is for 'hero' cells, using expensive technology to test the limits of a particular material, it is only tenuously linked to industrial production. There's lots of leeway for improvement in industrial production, which is what matters to the economy.
Second, improvements in efficiency are only one part of cost reductions. In the time that the cost of panels has dropped perhaps 50 fold you're only talking about a 1/3 to 1/2 increase in efficiency.
Third, there's always potential for other materials or structures to come to the fore. If we could find a cheap way of producing multi-junction cells then the ~30% theoretical efficiency limit disappears.
So, there's plenty of scope for continued improvements.
I really don't see why this is impossible. Hire a bunch of specialists, make robots build the cells end to end, then build a bunch of those robots.
Anything a human can make one of, it should be possible to make a robot build millions of with zero incremental human labour, as long as you invest enough upfront for the robots.
As yearly production escalates, even small increases to the "conversion efficiency"/"production cost" can yield high total returns on the investment.
It won't matter. Investment is hardly ever looked at in terms of total returns but only in terms of annual ROI as a percentage of the original outlay.
AFAICT, there are three ways to double the output of a solar cell: Double the area, double the efficiency, and move the cell to somewhere with twice as bright sunlight and install a cable. That one option presents intractable problems doesn't seem to matter very much when either of the two others are available.
And even if you drive down installation costs so you can roll out cheap cells en masse you'll eventually run into a space limit for some applications. There's only so much sun-facing rooftop on each building.