Primary & Final Energy.

Primary energy (TPES) is criticised because it overestimates the qty of C-free energy req'd to replace that generated by thermal energy. This because thermal energy generation is relatively inefficient at ave ~38%.

It's therefore perceived as consequently causing the global transition to C-free energy appear more difficult than need be. Fair call.

Primary Energy *does* measure the qty of thermal energy that has been displaced by C-free energy. Maybe it "looks back rather than forward"?

Total Final Consumption (TFC) below displays how the world uses energy, which seems to have labelled 'Final Energy'. Here I've included electricity generation, but it's a complicated diagram & not concise.

But the 3 pie-charts above can be combined, by considering only the C-free forms of energy and including @mzjacobson's specification for the greater efficiency of a 100% WWS energy system.
E.g.: SolarPV Final Energy = 1.7%*83%*20.8/42.9% = 0.7%.

Surprisingly the shares displayed in the Primary and Final Energy charts are very similar. This seems to be because the energy accounting for each divides respective qtys by similar numbers: Primary Energy divides by 38%, and Final Energy 42.9%.

Changes in Primary Energy are therefore informative and indicative of changes to final energy.

Opinions of primary energy often seem overly critical, usually associated with a Pollyanna attitude towards tech and the non-linear growth of renewable energy. How to be +ve *and* realistic?

Notes:
1. Yes I applied the efficiency of WWS to nuclear (maybe crude but is elec and a small %)
2. I could create a single Final Energy chart for 2018 using BP's data and assuming a % for biofuel.
3. Unless BECCS comes to fruition at scale, I doubt biofuels should be pursued.

@KevinClimate @Peters_Glen @DavidOsmond8 @simonahac