[nicup12345689]

This is the energy machine bottleneck, what kinds of machines are net-energy positive? Probably only hydrocarbon extraction/burning, nuclear, hydroelectric dams and maybe, maybe solar PV (barely, not convinced we can continue building solar panels without hydrocarbon or another source).

[flavius29663]

solar PVs are definitely producing more than put in. It takes years, as opposed to months or days for fossil fuels and nuclear, but it does pay back. look up EROI https://en.wikipedia.org/wiki/Energy_return_on_investment

[rgmerk]

And the EROI on solar is constantly improving. Every year we are using less material per cell to make more efficient cells.

[nicup12345689]

Exactly the point, EROI of PV is questionable. It relies on a lot of industry (mining for example) that is/was only possible from oil/"fossil"

[10u152]

Some food processing plants are net energy positive - they burn waste products and produce more then they need. But in general yes, only machines designed to produce energy, produce energy.