[maxander]

This comes down to the really interesting point in the article, which sadly is hidden a ways into it (just after the "Main Course" section begins):

"If the flow of energy is fixed, but we posit continued economic growth, then GDP continues to grow while energy remains at a fixed scale. This means that energy—a physically-constrained resource, mind—must become arbitrarily cheap as GDP continues to grow and leave energy in the dust."

It goes on to describe the paradox that if we can generate arbitrary wealth in such a system (through software, for example), it becomes possible to just buy all the energy[1] and break the system, which means that this doesn't constitute a really valid economic model.

And yes, it goes on to say that you can still have growth, perhaps even something that can be called "economic growth," but we've placed a fundamental limit on the growth of the GDP- the natural way economists would consider economic growth today.

[1] "Corner the energy market," if you're an Alpha Centauri fan.