With the rise of home-based and small-scale mining setups, especially in regions with surplus renewable energy, could Bitcoin mining evolve into a decentralized energy grid
You misunderstood between consumers and producers.
Bitcoin mining activities and Bitcoin miners consume energy, and basically they don't produce energy. So your question is so wrong and does not match with fundamentals of Bitcoin mining.
There are attempts to take advantage of heat created from Bitcoin mining activities to do something like a secondary energy sources but it does not change a fact that Bitcoin mining consumes energy rather than produces energy.
By the way, I think it is relevant to learn about Bitcoin and energy, including Bitcoin Energy FUDs.
End the FUD (Energy).Debunking the "Bitcoin is an environmental disaster" argument.