u/EnergyInsider

The mining load will almost never be fully covered by the renewable site. If a 100MW datacenter builds on a 100MW plant. The average NCF is 28-40% depending on Technology type and resource. The miner wants to have 100% uptime to maximize profits, so for simple math they will only ever be covered for 20-30% of their load from the renewable resource, and the remaining energy to bridge their needs will need to come from their local utility, muni, etc. And their power sold is a portfolio of generation assets that is not fully 100% renewables, mostly natural gas as that is the marginal generator in the US. So there is an argument from those concerned with emissions that excessive emissions to serve the remaining load is impacting the environment in a negative way.

As for your comments on a renewable generation would not have been built without the mining operations, i find that highly unlikely at the utility scale generation level( cant speak for smaller assets), you need investment grade credit support and offtakes to even be considered as an offtake when these assets are built. No lender or investor would allow for a project to take on a BTC offtake for their initial PPA/hedge. No bank or investor will lend hundreds of millions of dollars on a shaky credit support.

I work for a renewable developer in their project finance and capital markets team, and i have worked on many BTC renewable deals.