[amsat-bb] Waiting for Solar Panel Efficiency (Ha!)

Robert Bruninga bruninga at usna.edu
Wed Dec 30 17:05:57 UTC 2015

Compare the cost and efficiency of solar panels for cubesats and for your


The 10,000 Watt array for your house costs less than a 10 W array for a
cubesat satellite.

I get tired of the excuse, “Im waiting for higher efficiency cells” when
the cost of just doubling the efficiency from 15% to 30% is a factor of
1000 times more expensive.  You’ll be dead before the expensive ones even
come down by half (much less the 1000 to 1 needed to make them practical).

And in fact it will never ever happen.  Because a satellite builder will
pay a measly $10,000 to DOUBLE the power of his 4 inch satellite and so the
market for the highest efficiency cells will always get a premium price
because the satellite buyers will always pay max dollars for max power
independent of cost.

And there will never be a decaying cost or learning curve, because as soon
as someone comes up with a 32% solar cell, then the 30% technology is
ABANDONED because the space industry will all move to the 32% cells and be
happy to pay even more for the higher power and there is practically no
market for last year’s 30% cells that cost 1000 times more than existing
silicon cells at 15%.  And without a growing market for last year’s HIGH
efficiency cells, there will never be a learning curve and declining cost.

Meanwhile the cheap 15% cells being mass produced for the terrestrial solar
market in a MILLION times the volume at 1/1000 the cost already cost less
than a window of the same size!  Witness the cost reduction of 10 to 1 in
the last 10 years and the 2 to 1 reduction in the last 3 years with
improvements from 15% efficiency up to around 18% not by changing the
technology of the 60 year old simple silicon, but just optimizing the
manufacturing process (by the billions)…

Solar is here, Now.  And it won’t get any cheaper, because as the market
expands exponentially the demand for bazillions of watts of solar will soak
up every panel produced and homeowners are then competing with massive
utility scale purchases of millions of panels.  Solar panels now cost less
than just a window of the same size.  It is no longer the cost of the
panels, it is simply the cost of labor that drives the majority of cost
now.  You can buy solar panels for under $0.70 a watt but to have a
contractor installed system is hovering around $3.50 per watt and not going
down much at all.

Lastly, if you have sun, you KNOW eventually you will be going solar.  So
once you realize that, you should also realize that every electric bill you
pay from now on is just throwing money away which would have been better
invested in free electricity and 10% annual return for life on your roof or
in your yard.

Waiting gains nothing.  Even the solar panels I bought 4 years ago at twice
the price have already paid for themselves.  Waiting would have gained
nothing except 4 years of more wasted money to the utility and so many tons
of burned coal wasted into the air.  Here are some more thoughts…


Summary, Solar and Satellites… the same but 1000 times cheaper on Earth.

Bob, Wb4APR

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