... it probably is.
The latest example of this comes from a newspaper story, wherein a visiting professor (I can't remember what he was a professor of) was expounding on what the world would be like in 2070. Among other predictions, he felt we'd have dishwashers that cleaned the dishes without detergent, water - or energy.
The dog pricked up her ears when I read this out - she rather fancies herself as a detergent-&-water-free dishwasher, & regrets that opportunities are far & few between. But hopefully your critical thinking faculties have also engaged.
Detergent-free, water-free - OK; maybe it's technically possible to do this using something like ultrasound, for example. Marcus might be able to explain whether that's possible. But energy-free? Sorry, but cleaning the dishes (however it's done) is going to involve work (whether by dog, man or machine), & that in turn takes energy. We could probably be rather more efficient in how that energy's used, but that's another story...
(Although, I suppose... you could always put the dishes in with some dermestid beetles... but no, the turnaround time would probably be too long for that one to really catch on! And besides, the dermestids don't like fresh food - they're late-stage decomposers & they like their meat fairly whiffy)
I think this one really was too good to be true.