for me the biggest problem with self-driving cars is legal liability.
This is already covered. Brakes fail, tires blow out, mechanical failures happen. They kill people. Its been something that has happened plenty and gone trough the courts many times. Precedent has been set.
The average power you get out of 1GW of solar panels is at best 32% of the peak (in practice it is quite a bit lower, like 25%), and only in summer. It is much lower in the winter months, and you will often need to "time shift" all that energy.
These 3d printer nut jobs are going around saying things like "you will be able to just print that soon" and post articles like this. It gets tiresome. 3d printing is 20 years old and it can't even print the metal case to a iPhone (its forged to get the correct micro structure). It is useful for some parts and prototyping, but stop with "printed a real working gearbox" bullshit already.