Comment by feoren

Nobody said "infinite".

The upper asymptote of an S-curve is often called its "carrying capacity". We expect an inflection point about halfway toward this point. What do you think the maximum capacity of global solar energy is? The total amount of solar energy hitting Earth is about 4.4 * 10^16 watts -- 44,000 Terawatts. If we covered 1% of the Earth in solar panels at a meager 10% efficiency, that's 44 Terawatts -- this is a reasonable low estimate for the "carrying capacity" from total solar irradiance. We're at about 1 Terawatt right now. A high estimate (remember, this is the absolute maximum) might be 10% of the Earth at 20% efficiency -- 880 Terawatts. Of course, if we run out of space on Earth, there's always more space in ... well, space.

Another "carrying capacity" could be the materials needed for production. As TFA illustrates, we have enough different ways of producing solar panels that we are not anywhere near maxing this out either.

So I think there's pretty good justification to think we're still at the very early part of this S-curve.