But why would we use less cheaper energy?

A claim that confuses us. If we lard the world with renewables then we’ll all, in aggregate, use less energy. Well, that doesn’t confuse - if energy becomes more expensive then we’ll use less energy, yes. The confusion comes when we’re told that renewables will be cheaper and also that we’ll use less energy if it all comes from renewables. That’s not something that happens with our species.

But here we’ve the statement:

This is such an important and often overlooked point: A clean energy economy will use 40% less energy than a fossil fuel economy. As Hannah Ritchie writes in her newsletter this week, "Electrification is efficiency."

If we could just get someone at the back there to shout “Jevons!” for us?

But leave Jevons out of this because we’re not trying to be that sophisticated here. We might also insert that ritual mention of the Nordhaus work in lighting - as it has declined in price over the centuries the percentage of income spent upon it has stayed static - but again we don’t need to go that far into complexity.

We can just stay with really simple supply and demand. With us humans if something gets cheaper then we buy or use more of it. How much more depends upon the elasticity of demand with respect to price (which is what gives Jevons!) but stick with that very simple first order effect. Also, if something becomes more expensive we use less of it. This is true enough, often enough, that if we see falling demand for something then we can usefully opine that the price must have risen. In fact, if we assume that the price relative to alternatives has risen then we will be correct all the time.

OK. So, now we’re being told that humanity will use less energy if it’s all renewables. That jibes with - actually, flatly contradicts - the idea that energy will become cheaper when it’s all renewables. In fact, we’re on really safe ground if we insist that the only reason people will use less energy is if it becomes more expensive.

So, the assumption that the world will use less energy is that insistence that renewables are going to make energy more expensive. No, efficiency doesn’t change this. Even if we assume that there is greater efficiency that just means that we’ll all turn the thermostat up (or, for A/C, down). On the simple grounds that that’s what humans do in response to a change in prices.

Which is interesting, no? They’re not just indicating that maybe renewables aren’t cheap they’re flat out insisting they’re not.