There was no bug. He was relying on wind for a large percentage of his energy income, and wind output dropped to 0.2 per wind generator. He had a ton of mexes and his metal production was faster than his energy production. Because of these two reasons he ran out of energy.

When the map says that wind power is 1-4, what is the actual range that wind mills can produce?

I think wind needs a redo. No income at all is really crippling to the point that I never make it early.

I would change it to say 0.5 to 2 income so compared to solar it is at worse half and at best double. Height would increase max income.

agree, floor of zero encourages mixed energy sourcing