Over unity is a false belief and will never ever ever work I can promise that! But using the naturally occurring energy around us to do work is however obviously possible and countless forms of that free naturally occurring energy can be captured and are used every day.
I have always found it odd that the self proclaimed experts seem to think that free energy is impossible. All of the energy that nature tosses around us every day is free to capture and use. The devices that capture that energy are not! Wind power is free but the wind generator that turns it into electricity cost time, materials, and money. Same with solar thermal and solar electric. That heat and light cost us nothing but the devices that convert it into an energy form we can use do cost something.
We spend billions of dollars a year on air conditioning to pump out that unwanted heat energy that nature keeps sending in through the windows and doors for free.
Most of the supposed over unity device problems come down to quantifying what naturally occurring source of energy is being harnessed to do work. Once the energy source is quantified its no longer over unity. Just cleaver energy harvesting and conversion.
A simple example is this.
Is my house suffering from an obvious over unity issue because it heats up during the day even though I am not putting any energy I pay for into heating it? Or is the sun shining in the windows?
I dont always want it, I never built anything to purposely harvest and store it, but its there for no efforts or costs to me.
Argue it all you want but I will always define that as a measurable and usable 'free energy' source and no laws of physics or thermal dynamics have been broken!