RE:RE:RE:RE:A useful Global Perspective on energy and emissions The whole subject of efficiency is an interesting one, especially when looking at the entire lifecycle of products including materials and energy used to produce and also recycling costs. There often isn't always a lot of consideration given to how something is going to be used - for example the efficiency of an EV looks a lot better if I charge it and then drive it continuously until it needs to be charged again as compared to driving it short distances with long periods in between as then the battery discharge rate has to be taken into account. It just demonstrates I think that when comparing numbers the conditions and any assumptions made need to be considered. I think that is why you see such variation in quoted efficiencies for technologies and products - I may be mistaken, but I think the Prius is currently rated as the most efficient ICE technology based car available in the US