On the power plants side, it's about costs. I don't think it makes sense to compare different plant types. But you could take solar as an example - is it bette

On the power plants side, it's about costs. I don't think it makes sense to compare different plant types. But you could take solar as an example - is it better to use up twice as much roof space/desert if the overall design is cheaper that way? Probably. Yet, all else being equal, the more efficient design is of course preferable, less stuff to install, less material usage, so technological advances tends to push for higher efficiency, I think. On the consumer side, just look up the efficiency in what interests you. It should be easy enough to find numbers online. If you're in the EU, most household appliances have a mandatory rating from G to A, with the least efficient appliances having a disturbing red G, while the best have a nice green A: https://en.wikipedia.org/wiki/European_Union_energy_label https://en.wikipedia.org/wiki/European_Union_energy_label As you can see in the example in Wikipedia, the differences between the ratings are significant. When this thing started, you could buy a G fridge - I think those may have been the norm. I looked up an internet dealer right now, and the lowest rating I could find for sale is A+, with A++ being the norm. In a year or two, A+++ is probably the norm. It has worked like the MHz wars on PC, amazing really. As long as there's competition and someone puts energy efficiency in the spotlight, things can actually change.