Comment by jandrese
The 40% figure is supposed to be "wire-to-wire", but they do list that as the "target efficiency" which suggests it may be somewhat aspirational. It presumably doesn't include the energy needed to extract and refine the oil into whatever kind of burnable fuel you are using, nor the energy necessary to extract and then blend in the sodium additive.
And at the bottom they seem to indicate they are still in the "proving feasibility" stage.
I read this all as: "this is a POC we have, and if we can get it to 40% efficiency than it might make sense (otherwise who cares, just use a conventional generator)"