no transmutation at all
as the paragraph before last says: "200,000 litres should weigh 18 kg."
and from the 3rd paragraph "If the SHT barrel was equivalent to a 159 litre oil barrel, the starting water had only around 18 kg of hydrogen and 141 kg of oxygen"
So it's simple electrolysis, there was 18kg of hydrogen in the original water that's now been extracted to 18kg (200,000 l, or 2000 m^3) of H2. According to this: https://en.wikipedia.org/wiki/Electrolysis_of_water
current industrial electrolysis consumes 2.94 kWh/m^3 of hydrogen produced, so would require 5880 kWh.
This statement from the release: “the external energy needed to make these 208,678 litres of pure hydrogen ... averaged at 414 watt hour = 4.6 volts x 90 amps.” is missing an essential part of the release, which is that teh process was completed in 1 hr (without that qualification you just have 414W for an indeterminate time, adding teh 1hr qualifier brings us to the claimed 414Wh)
"[the performance of the test system] increased to 127 cfm or 215,800 liters per hour"
So they are basically saying that on an experimental / non-industrial test rig, they required 414Wh to do what the current best industria rigs requires 5880kWh to do.
That is an extraordinary claim, and as such requires extraordinary proof.