So there is technically such a known limit due to a link between information-theoretic entropy and thermodynamic entropy, which provides a lower bound on energy

So there is technically such a known limit due to a link between information-theoretic entropy and thermodynamic entropy, which provides a lower bound on energy usage for a particular digital circuit via the second law of thermodynamics. In simpler terms, there is an unavoidable generation of heat when you "throw bits away" like AND and OR gates do. However we are several orders of magnitude away from that efficiency bound in today's chips, so your analogy to LED bulbs is more apt than you may realize: LED bulbs are still far away from their theoretical maximum efficiency, but they're still a massive improvement over incandescent bulbs. If you want to know more about this limitation, I suggest looking at a way of organizing computation that avoids this issue called "reversible computing"[1]. As I said, it won't be of practical significance for classical computing for a long while, but it's actually pretty fleshed out theoretically. [1]: https://en.wikipedia.org/wiki/Reversible_computing https://en.wikipedia.org/wiki/Reversible_computing