That requires you to assume a certain mix of energy used to manufacture the thing.

It reflects the current reality. We're not going to replace everything with nuclear power anytime soon.

True. However, while it is possible to make any kind of car with 100% renewable embodied energy, it is quite impossible to operate an ICE car on renewable.

that study is problematic because while they look at the cradle to gate cost of the electric drivertrain including battery, comparing to the ICE car drivetrain, they don't look at all the cost of Petrol + all the unaccounted for externalities that go into it's extraction and delivery. A good comparison would include the cost of electricity extraction both for the ICE car and the electric and then do the comparison. As it stands, this study tells us that Electric cars are more 'expensive' than ICE cars.

I'm confused by what you've written here.

When you say they "left out the petrol", are you assuming that a better analysis would assume that the petrol is never made in the first place?

I mean, that might be the wish but we don't yet live in a world where the gas will stay in the ground if we don't use it to fuel one automobile at the margin.

Child has it. The way this study is written, we're asked to compare more or less the carbon impact of an empty gas tank and the battery pack. That seems a bit unrealistic to me. yes the drivetrain is different and therefore more costly, but when it comes down to it, looking at the examples in the paper, the comparison is between the battery pack and an empty gas tank. That seems disingenuous to the broader point of carbon emissions for the entire life-cycle of the vehicles, which presumably would include use.

Which approach is "more realistic" depends on whether you are evaluating the decision between an electric car and a gas car at the margin, or not.

If it's you as a consumer buying the next car to be produced, then it is entirely appropriate to compare it that way, because your single purchase will not change the entire life cycle.

I think their point was that it seems unfair to count up all the of the embodied energy of an electric car's batteries, but to only count the potential energy of the ICE car's fuel.