Car rental - electric, fuel, or hybrid

But neither does it sound like a very good idea to take off in a fully electric car for the very first time ever when I am in another country

That is very very true,

Electric vehicle adoption in Spain is still lower than in many other European countries, so you’ll find plenty of gas stations everywhere. That said, there are also many EV charging stations, so I’d simply recommend renting the car you prefer.

All toll and mayor roads have charging stations along the route. In my experience, Tesla Superchargers are much more reliable than most other charging networks (with IONITY being one of the few comparable alternatives), so I’d recommend using Tesla Superchargers whenever possible. You don’t need to rent a Tesla to use them — all electric cars are compatible with Tesla Superchargers.

You will have to install Tesla app in your phone, add your credit card, etc.

If you rent a non-Tesla EV, A Better Routeplanner is very useful for planning charging stops. I drove from Bilbao to Andalusia a few weeks ago using only Tesla Superchargers, and the experience was very smooth.

Outside the toll roads, you can find charging stations at most supermarkets and large parkings.

Read Nigel's post in this topic ( scroll down a bit)

https://community.ricksteves.com/travel-forum/france/electric-car-in-france

Electric rentals cars and Vespas/motorcycles are things you should not try for the 1st time while on vacation.

1. You will not find a shortage of gasoline stations in Spain. Fully electric vehicles are less than 10% in the Spanish market. Hybrid is the dominant segment (including plug in hybrid), with more than half of the vehicles, and that is why many rentals are hybrids, but hybrids use gasoline as well. Rental car companies want cars in their fleet that are easy to resell in the used car market. If you want automatic vehicles, those are really the only choices nowadays: Hybrid or BEV. If you want gasoline vehicles, a manual transmission will certainly mean gasoline fueled car.

TTM,
I had something of a similar research project for a slightly earlier trip and a couple of random
inputs:

• the airport seems a better place to start driving from as opposed to Chamartin, especially
  if you are heading north or northwest; you can avoid driving in the city to start. Yes, you have
  to go back into Madrid to catch your train after you drop the car off at the airport, but that
  should be pretty straightforward.

• you may have suggested this yourself at some point, but somehow I found out about Kemwel,
  which is a branch/subsidiary of AutoEurope. A random booking does show they offer regular
  gas-powered cars, but not knowing your dates, perhaps you're looking at a busy time?

Also, for the booking I made, for some reason, Kemwel offered a zero-deductible rate that
was less than any of their other rates. I have no reason why, but it seemed like a good deal.
You might want to be on the lookout for that option as well.

Ok, this all makes sense and reassures me.

Joe, I do think it’s not the right time to start with new mechanical things - I rent frequently but I always have to run through the basics. So as long as I can find a car not electric, that’s better. I do love hybrid cars, but they really WERE a lot more expensive (although I know I save money on fuel costs).

shoeflyer, I will take a look at Kemwel. Now that you say that, I have read the name here but have never researched or used them. Thanks for that and input on rental location.

Thanks for the reassurance, Roberto and BasqueCountryGuide! At least twice in my renting life, I have received (as the only choice) NOT what I requested. So it can happen - good to know I won’t need to panic. Ha!