Really interest info abt Solar. But I think there is a mistake in the post. When the Eco tax is on It deduct 2 sim from solar.
Eco tax - tax for eco program - "For a 5% tax The President can boost income from Wind Turbines and Solar Plants "
So it means We can have maximum 13 sim (5 base income + 2 ECO + 8 Dyson Sphere and -2 for eco) when the eco tax is on.