I've seen it stated by many sources that the Defender will come with a diesel. It may not come with one at launch, but I have a feeling that LR will add it in year 2 or so as an attempt to bolster sales once the initial hype inevitably dies down. Furthermore, JLR offers a diesel in 3 of their 6 current model offerings (I would've said 4, but it appears that the 2020 Velar no longer offers it). I doubt they wouldn't offer it on the Defender.
I've been told by someone from LRNA that there are no plans for a diesel version of the Defender for the US market. I'm hoping they will change their minds if enough of us let them know that it is what the buyers of this vehicle want.
I'm guessing that sales of the diesel versions of the Discovery 5, RRS and Velar (as well as the diesel F-Pace) did not live up to their expectations. My local dealer sold a bunch of diesel F-paces as corporate cars and says they will really miss the sales revenue from that vehicle. Diesel is less expensive than premium fuel in my part of the southeast and the extended range you get from diesel power along with the torque characteristics of a diesel should make it the premium choice of power plant in a new Defender.
I guess I can see that the typical buyer of a Range Rover really doesn't care about the cost of fuel but I'm surprised that the diesel Discovery wasn't more in demand. If the look of the Discovery 5 hadn't been so polarizing I would bet it would have sold much better.
If Land Rover had brought the diesel LR4 into this country it would have sold like hotcakes.
I can get from Atlanta to upstate New York (just east of Binghamton) in our diesel Discovery 5 on $80 worth of fuel carrying the two of us, a large dog, an Engel fridge and more luggage than any two people really need and do it in comfort in two days of driving.
We stop for fuel in Northern Virginia before crossing into Taxsylvania (50 cent a gallon higher fuel prices - highest in the United States). I was hoping to order a new Defender immediately with a diesel engine as it meets my requirements for what I want out of my next Land Rover. As it is now I'm just going to continue driving the Discovery and see if LRNA gets its head out of its ass.