What is your prediction for experimental solar cell efficiencies?

Question

The highest is around 40% and the lower end ones are around 30 % as off 2008.

Answer 1

I agree with the other posters but would like to add that silicon could be used more efficiently as a passive environmental control system in buildings than as a solar cell because of the inherent properties of silicon.

Answer 2

I suspect that experimental solar cell efficiencies will be / are less important to most of us than the ability to inexpensively mass-produce the solar cells.  

Unless you are dealing with space exploration, solar cell efficiencies are much less of a consideration than the installed cost per watt of solar cells.  Recent advances in thin film technologies show promise in reducing solar cell costs per watt - even though they are likely to be less efficient than traditional silicon cell panels.  Once the cost per watt of solar cells becomes competitive with other energy sources, they will be installed as a regular part of building construction.  And the efficiency becomes even less important, because large quantities of them can be installed as part of integrated roofing systems, etc.

To me, this is a surprising development.  I expected solar to eventually become cost effective by having efficiencies increase, and costs per square foot to stay the same.   The possibility of having efficiencies decrease, but costs to decrease even more, is a very exciting, and unexpected, situation.

Answer 3

Efficiency needs to be tied to manufacturing cost.  For example, if I can build a 30% model for half the cost of a 40% design then I can produce a lot more electricity per dollar with the 30% kind.

The breakthrough with solar won't be high efficiency, it will be low manufacturing cost.