Let's assume for argument's sake that the Flying Scots have indeed figured out how to get something for nothing: a machine that generates energy without consuming fuel of any type? A net producer, to use some of their own rhetoric.

We can even dress it up with some kind of pseudoscientific terminolgy; it taps the quantum foam, or siphons energy from other dimensions, or efficiently converts matter directly to energy without any troublesome nuclear or thermonuclear reactions. After all, sailboats convert wind energy to boat kinetic energy, and that isn't even violating physical laws: the wind blows because of solar heating. Sailboats move around and the global breeze is slightly diminished as a result. Nobody notices.

OK, so we've got a box, let's say it's roughly the size of an automobile engine, and puts out about the same power. We can kiss internal combustion good-bye and the Middle East turns overnight into the economic equivalent of Sub-Saharan Africa. They won't even be able to afford pwder and ball for their muskets. We won't even need petroleum for lubricants because replacing machinery will be cheaper than keeping it greased.

The automobile engine and the thermoelectric plant and the jet engine are replaced overnight. Every appliance now in the modern world is converted to the new energy source, so the energy consumed by the planet is comparable to what it is now, although we no longer need consume fossil fuel to do it.

But energy consumption remains the same, in fact, it increases, since cost is no longer a concern, and inefficiency will no longer matter either.
Not only that, with free energy, manufacturing and transport will suddenly explode, (although I'm sure will still be kept high enough to keep wages manageably low) and there will be massive shortages in other raw materials (SUVs will become mandatory, by law, in all red states!). Global energy consumption, which has been doublling every ten years or so anyway will suddenly go through the roof.

The total energy pumped into the environment as waste heat will skyrocket, and even machines that do useful work do not consume energy, they just transform it into waste heat which goes into.....GLOBAL WARMING! The atmosphere will heat up and evaporate into space...and the drop in air pressure will cause volcanoes to erupt world-wide...like zits with the bends (no problem, energy's cheap, we'll just air-condition them (except where do we put the exhaust vents?)) The Earth will become bright in the infrared and be mistaken for a Dyson sphere by marauding space aliens who will come and....Kreegah! As Fat Freddy says.

Forget the Scottish device, there are some things Man was never meant to know.