If the local grid can't provide that then upgrades are needed. They may pay enough for that but then the energy needs to be sourced, which may mean extra fossil

If the local grid can't provide that then upgrades are needed. They may pay enough for that but then the energy needs to be sourced, which may mean extra fossil fuels and potentially breaking promises made on move-in towards a higher % renewable use. It can be about more than the financial price. Even if it was about the cost of sourcing and provision, someone that big will bargain down close to the minimum. There will be little benefit to share around elsewhere, unless of course this is made specifically part of the bargain (they can build, in exchange _they_ improve local infrastructure to cope, as greenly as the locals desire, with stated benefits for the area with compensation clauses for if said benefits don't turn up).