Currently ingame, there is absolutely zero reason to build the Solar Panel blocks ingame. As titanium (which can be found in the spawn system) generators are just superior.
This is only worsened by the progression further in the game as generators with each tier progressively produce more and more power, while Solar Panels recieve no similiar gains.
Some Examples:
100x1x100 Titanium Solar Panel: 20.4Gw
100x1x100 Titanium Generator: 825Gw
100x1x100 Ogonite Solar Panel: 20.4Gw
100x1x100 Ogonite Generator: 1500Gw
If the same scaling of Titanium>Ogonite is applied to solar panels, the resultant power output would be 36.72Gw.