Mini Powerplant: two small blocks that can power an average American home (engadget.com)

I was a bit distracted while the interview was playing, but what I gathered is that their efficiency in converting chemical energy (specifically, so far, natural gas and oxygen) to electricity -- perhaps, per a comment I saw elsewhere, when the resulting heat can also be used and so considered part of the equation -- is about twice that of utility generated and delivered electric power.

I don't know whether my understanding is correct, but that's how I currently understand the comments regarding greater efficiency and cost savings.