Fuel produced from anything farmed might be carbon neutral, but the process of farming itself has a huge impact on the environment. Also, we just have by far not enough farmland to come even close in supplying the traffic sector with fuels - while in many regions there still is a shortage of food. So with the exception of processing waste from food production, it is environmental-negative to use grown fuels. Solar cells are more than 10x more efficient per area used and can be mounted on top of roofs etc.
That is a very good point. We have quite a few applications, where we will need fuel for quite some time to come, let us reserve all the "reneweable" fuels for those applications. Electric cars are a thing, electric airplanes are unfortunately only at their very beginning.
True. But how much HVO100 can you personally produce?
Solar is easy to produce locally, even on your own roof. Also electric cars typically turn around 85% of the energy into forward motion. Because it's local there's minimal distribution costs. Additionally grid size installations are competing with coal, natural gas, and similar sources quite well on price.
Gas cars are around 15% efficient, and diesels are only slightly higher. Anything like gas has substantial costs in distribution, and of course you have to drive to/from gas stations (instead of just charging at home/work.
So even if HVO100 is 100% renewable, it's not going to be cost efficient, or energy efficient.... so why bother?
Sure a Prius can get as high as 38% (at the cost of two complete drive trains). But what about the average vehicle sold in 2018?
I suspect you'd be well below the 30% efficiency again. At least in the USA the Prius isn't particularly popular (except to trade in for a model 3). The demand is for the small crossover and SUV segments.
There's good reasons beside carbon to avoid running your car on what's pretty much liquid margarine. Arable land can't be spared for it on a global scale. And it fills the air with the usual medically inadvisable smut and gases.
Airplanes, on the other hand, that might be a good thing.
I’m not sure why the grid mix is relevant at this time.
electric car usage in the US is less than 1 million cars.
My point was that that the electricity can come from a variety of sources, including fossil fuels. Coal is dying. Natural gas is cheaper and much cleaner.