If room temperature superconductors existed that were practical for transmission scale wires, it would be possible to make a global superconducting electrical grid. The middle East could fill their desert with solar panels and export that electricity to Europe. The sunny side of the planet could export solar power to the nighttime side of the planet. You could make electrical motors out of it a fraction of the size of current motors, like 1000 of horsepower out of a soda can, which would revolutionize the design of pretty much everything in the world with moving parts. Mechanical transmissions would go the way of the vacuum tube. Any vehicle or ship that's not completely electrified would be hybrid electric at least. You could also miniaturize transformers which has a lot more implications for making everything that uses a lot of power to be much more powerful and cheaper.