The 13% higher CO2 per *gallon* figure ignores the higher thermal efficiency of diesels, because it's purely the fuel.

Burn a gallon of diesel, get 22.4 pounds of CO2, end of story. Burn a gallon of gasoline, get 19.6 pounds of CO2 (although it's worth noting that E10 is lower tailpipe CO2). Basically, there's no free lunch - the added energy in a gallon of diesel fuel comes from a higher density of hydrocarbons.

In any case, diesels aren't actually considered in this data at all - it's purely gasoline-fueled vehicles versus electric vehicles. You have to get 80 miles per gallon of gasoline to match the average EV on the roads, using 2016 grid data, and 2011-2017 sales data.

So, a diesel, emitting 13% more per gallon, needs to get 90.4 MPG to match the EV, assuming that the amount of CO2 from producing the energy in diesel fuel is the same as gasoline. That's independent of how the energy is handled by the car (whether it's a hybrid or not) - if you can get 90.4 MPG combined in your diesel, more power to you. (However, an EV that's that efficient could likely beat your 90.4 MPG diesel.)