Gyre, without getting into a big long explanation, the source of the energy is generally referred to as "zero point energy". There are various claims for it's density. One claim is that "if all the energy contained in 1 cubic centimeter was changed into matter, it would produce more matter than exists in the observable universe."
There are other claims;
"Nobel Laureate Richard Feynman and one of Einstein.s protigis, John Wheeler, calculated that there is more than enough energy in the volume of a coffee cup to evaporate all the worlds. oceans"
The Nobel prizes were long ago awarded for proving the existence of ZPE.. The work of Tesla on toroid transformers was followed up by Bob Boyce. It was also demonstrated in the TPU. Stan Meyers proved that an IC engine could be run on water. The current efforts are centered in reducing water to HHO rather than directly igniting it. Stan Meyers was poisoned for his efforts. He was directly igniting it. The HHO efforts of Boyce, et al are using a parallel-plate device to produce the HHO from water.
Hundreds of researchers have long ago exceeded the "Faraday Limit" at producing HHO gas.
The most interesting part of all this is the fact that we have almost NO understanding of water. It has been proven over and over that the HHO gas resulting from a certain production method [Brown's gas], can be used to remove the radioactivity from radioactive elements and isotopes. Obviously, this contradicts much of what we hold true in our beliefs of radioactivity.
The other interesting area is transmutation. Researchers put pure Palladium electrodes in pure water and apply current,,,,, cold-fusion experiments. Under later analysis, they find dozens of elements present. There is no explanation except for low energy transmutation. This too flies in the face of much of our dearly held theories.
Science understands VERY little of the properties of water.
I don't post things because I believe that they are the absolute truth. I post them because I believe that they should be considered.