Well the paper shows that looking for signatures of photovoltaics is an impractical strategy if not impossible. The only other games in town, if we're talking

Well the paper shows that looking for signatures of photovoltaics is an impractical strategy if not impossible. The only other games in town, if we're talking huge amounts of power, and ignoring the speculative "beyond", are fission and chemical combustion. Unlike PVs these can be expected to alter the planet's atmosphere distinctively, and that is the thing we can actually observe during transit events, in contrast to panels (and dams, wind turbines, geothermal etc) down on the surface. Apparently it's worth bothering just to remain inconspicuous. Aliens are clearly doing everything possible just to hide themselves from Earth.