The 'primary energy' furphy

 From a Twitter thread by Dustin Benton

I find that quoting 'primary energy' is a useful heuristic for misinformation, which this piece absolutely is. Here's why:

Primary energy is energy input. What you care about is 'final energy demand': the energy [for] the wheels of your car, for example. This matters because fossil fuelled machines waste so much primary energy that it makes it look hard to replace them with clean energy. Some comparisons:

- Petrol cars turn ~25% of 'primary energy' into motion; EVs 85%.

- Coal power turns ~30% of primary energy into electricity, gas ~50%, solar and wind 100%

- boilers turn 85% of primary energy into heat; heat pumps 300%!

Clean energy doesn't have to replace all primary energy.

A real example: a Mustang has a 16 gallon tank, containing 535kWh of (primary) energy. You might think the Tesla would need a 535kWh battery to match its range. Wrong! The Tesla goes as far with a 103kWh battery because it is efficient (and fast!)

So, when people quote 'primary energy', unless you're in a technical conversation with an energy wonk, they're probably misleading you - possibly on purpose. Don't fall for it!

 

[This is a nice explanation of the difference between primary energy and usable energy]

(Source)