There are a lot of Elephants in the rooms right now regarding new forms of energy to replace fossil fuels . The largest is indeed how to "produce" those alternative energies ,Nuclear fusion reactors are being mentioned to give the necessary electricity , but its technology is not yet mature and their environmental impact is only Zero when they work correctly.
So Greta has still some future ..
Another elephant for the future electrical transpiration future system we are told is coming ( whether aircraft or cars) is the cost of the batteries re-loading . Not only the Kw needed , but also the cost of setting up the recharge stations in sufficient numbers everywhere including the cabling / transportation required. This infrastructure will have a huge cost that will have to be passed on to the user..