Greetings All
This just a thought to consider.
How the term "free energy" rakes against the nerves.
It would best be called "over unity investment"
You still have to spend money for the windmills, solar panels, the materials of whatever we use to collect the available energy. Then it finally pays for itself from freeing you from spending that much money to the power grid. So you get more back from your investment. More out than in = over unity. ;)
LOL, that is a good way to look at it.