That is very much a it depends. The best combined cycle power plants get around 60% efficient. The gas engine in your car is in the ideal case around 45% efficient - but the way you drive in the real world is only about 20-30% efficient.
replyIndeed. That exponential has renewables being ~100% of electricity in the early to mid 2030s, and approximately ~100% of all power in the late 2030s to early 2040s even without the efficiency improvement from direct electricity use.
reply> only ~20-30% of the energy in the fuel turns into useful work, while electricity is much, much more efficient. So, we need much less of it.
replyIsn't a lot of energy used for heating, not work?
Yes but by a weird coincidence most of that heat can be provided by heat pumps at a similar 3-5x ratio.
reply(it's not a coincidence, it's the exact opposite formula. You can only get 20% out of a certain heat engine because running it in reverse would be a 500% efficient heat pump, and the closed loop can't be more than 100%. This still applies even if the engine isn't built to be able to act as a heat pump, because some other engine could.)
replyMaybe, but that other 70-80% is waste - we could turn it into useful heat, but instead we vent it to the environment.
replyI've seen plans to run an engine in your furnace, thus creating both electric (at 20-30%, and capturing the rest as heat to the house. I've never seen this in the real world and experts who have looked as those systems said they won't enter a building that has one using that design. (it is possible to make a design they would trust, but they haven't seen any)
They account for this.
reply> Primary energy is based on the substitution method and measured in terawatt-hours.