If the letters/words in the quote are correctly kilojoules, seconds, and liters, then it doesn't make sense. You would want to know how much energy (J) it take

If the letters/words in the quote are correctly kilojoules, seconds, and liters, then it doesn't make sense. You would want to know how much energy (J) it takes to separate a given volume of gas. The quoted statement talks about power (rate, J/s), not energy. It doesn't make sense. I don't know the experiment in detail, but even I can see that mismatch.