But some of that energy is FREE. The sun. If you plant an oak tree and do nothing to it for a number of years, you can cut it down and burn it and get more energy out of it than you used to plant it and cut it. Same situation here.
The other morning, my sidewalk was covered with a thin layer of snow. The sun came out and melted it even though it was below freezing. For free. No salt, no physical labor, no snowblower.
That’s the point.