Here is study referenced in case interested - https://www.sciencedirect.com/science/article/abs/pii/S0967070X2600051X

First, I want to thank you for taking the time to engage on this topic, and also finding this great research paper. There's always room for criticism in a source, but overall this is a great analysis done by the paper's authors within the scope they define. I only have access to the abstract through the link, but may see if I can find the full paper from my library.

Pros of the paper:

• the WTW (Well-to-Well) metric the authors use does encompass nearly all of the energy/emissions from using the stated fossil fuel for transpiration. This is a great way to have an apples-to-apples comparison of the various sources of energy with regard to their pollution cost in vehicles of various types which is our core question.
• For Diesel the authors factored in emissions including not only CO2, but also Particulate Matter and oxides of Nitrogen which is much worse from diesel emissions than other forms of petroleum compared to gasoline or methane combustion. I appreciate this level of detail from the authors. However, in just the abstract I can't see the formula for how they define a percentage of pollution on these other to inputs.

Cons of the paper:

• the WTW (Well-to-Well) metric starts at the well. There's no accounting for the exploration pollution associated with fossil fuels (or battery materials for that matter). As an example, the Deepwater Horizon oil disaster was the largest oil spill as well as the largest release of methane in history. Deepwater Horizon was not an active production well. It was an exploration well (which is the step before production). Therefore it wouldn't be included in the WTW metric, yet represents a huge amount of pollution that would not exist if we weren't using oil and methane.

Also, to our question about coal derived power for EVs, we may have enough information from the authors to extrapolate the coal figure. Since the paper includes detailed analysis of methane generated power, we can likely get the efficiency and emissions numbers for that power source. This will let us use the author's methods for defining the percentage of efficiency for comparrison once we get the coal inputs. We can likely get the coal inputs from looking at an existing coal power plant and getting its ingested coal, CO2 cost for extraction of that amount of coal, then the published emissions numbers from the plant for the KWh of electrical energy generated over a set period.

Overall, this paper, and your read of it is a fantastic contribution to the conversation. Thank you!