The geostationary orbit is 36,000 km in radius, an order of magnitude larger that the radius of the Earth. That, and the obliquity of the ecliptic, means that t

The geostationary orbit is 36,000 km in radius, an order of magnitude larger that the radius of the Earth. That, and the obliquity of the ecliptic, means that the satellite is only shaded by the earth for a tiny fraction of the time when the orbit crosses the ecliptic during the solstice, basically with about the same frequency as a lunar eclipse. Shading is not a problem.