Maximum Solar Capability to Convert Electeicity

[timpierc]

I'm probably just googling the wrong terms. What I'm trying to figure out is the maximum theoretical capability of a silicon (or other material) solar panel to convert sunlight into electricity.

What I'm asking is analogous to the thermodynamic efficiencies of various heat technologies. The maximum theoretical efficiency of a coal power plant is around 45%. Combined gas/coal is around 65%, diesel and gas engines can never be above 40% (this is all from my memory back in my collage thermo classes, please don't hold me to these numbers ).

My point is the laws of thermodynamics place a maximum limit of usable power that a specific heat technology can attain. The rest goes to waste as heat.

For solar the earth receives around 1000 watts per square meter. Obviously a solar panel can't convert all of those watts into electricity. What is literally the line where physics says to solar technology "you shall not pass!"

Links to references would be great!

Many thanks,

Tim

 

[AndreN]

Shockley–Queisser limit - Wikipedia

 

[nwdiver]

Shockley–Queisser limit - Wikipedia

Yep... there's a lot of different 'tricks' you can use but it's likely that the max is <40%.

It's important to keep in mind that efficiency is only part of the equation. Unlike other energy sources the 'fuel' is free and there's no cost to dispose of the waste heat. If I asked you if you wanted 10% of the $$$ behind door A OR 90% of the $$$ behind door B you don't really have enough information to make an informed choice. There could be $1M behind door A and $10 behind door B....

We get 1kW per sq meter of solar energy.... even if we only harvest at 20% efficiency that's still A LOT of power... A LOT of power.... far more than we can EVER use.

 

[wycolo]

Grape Solar full size panels are now listed as 330 watts each which is about 0.4 horsepower. This is a bit more than the 265 watt panels that were popular a year or so ago, so a bit of progress has been made. But the industry probably has a 'standard' sunshine rating of some sort to test measure panel output. Like that found on Caesar's Palace parking lot at noon on a clear Sept 21st in Las Vegas, NV.
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