No, the old kind, except consumed in times and places where it would have gone to waste before.
Energy companies around the world could use surplus energy in times of low demand to mine Bitcoins. This would be a really efficient scenario.
Exactly. Also, there are a lot of electric heaters in the world that could be replaced with mining rigs.
Mining is a highly competitive market, so it will drive towards these kinds of solutions where the marginal cost of electricity is zero.
Nobody will be buying electricity to mine anymore, 6 months from now.