I'm just not entirely convinced of the premise that energy consumption on that scale would be necessary for an advanced civilization. Particle accelerators would be a reasonable possibility though.
I'm not sure I understand the relevance of what Summers is saying. He's talking about a current slowdown in growth, and arguing for expansionary monetary policy. This article is claiming that there's a limited amount of growth that we can expect in the longterm, because we'll run out of sources of energy. But Summers isn't talking about energy as a limit..indeed, he's saying commodity prices are depressed.
The other article isn't entirely arguing that energy is a fundamental limit, although the example it gives is pretty hilarious. It's ultimately arguing that there are fundamentally limited things for capital to invest in and grow.
The only argument I see is that energy places a limit on growth. Now, one might think that if energy is one limit, there must be others, but I can't find that argument actually presented.