I don't know if that's the right metric to look at. There's not a huge difference in going from 91% efficiency (10:1) to 99.5% efficiency (200:1). What's more

I don't know if that's the right metric to look at. There's not a huge difference in going from 91% efficiency (10:1) to 99.5% efficiency (200:1). What's more concerning are the other negative externalities -- pollution, ecosystem destruction, etc, as described in the original article. This won't be captured by looking at energy stored vs. energy used in production.