On 8/16/2015 11:08 AM, bilou wrote:

There is also the regularly reapearing projects of transmitting
power from a geostationnary solar panel to ground by microwave.
I have great difficulties to understand how it could be efficient.

I'm lost. What is the problem? If you are worried about the losses in
transmitting power to the ground, I think you are missing the point.
The only thing that matters is the amount of power delivered, vs. the
cost of the system. In other words, you are comparing apples to
oranges. You may have losses in the transmission of power, but all
power systems have losses. The important part is the system, not one
isolated portion of it. The point of the orbital PV cells is to greatly
increase their power output. As long as those gains can make up for
other system losses *and* the increased cost of the system, the system
costs less per watt.

I believe the only real obstacle to orbital PV power is concerns about
the safety of beaming the power back to earth without possibility of
frying people.

--

Rick