Obviously there needs to be some amount of battery storage of energy too, but once the storage capacity meets the needs of the local grid, and the batteries are full... what do you do with the excess power?
May as well mine Bitcoin with it and make some profit on that excess energy.
Energy buyer of first and last resort.
And even if you built out more transmission, you're still limited by how far you can go. On top of that the infrastructure needed to transmit over large distances (1000km) is huge. Then there's a bunch of regulatory red tape to cut through, NIMBY push-back etc.
It's unlikely that a power company has the time, resources, and money to set up such massive transmission projects on top of their core business.
However, it's relatively easy to truck in a bunch of shipping containers filled with ASICs and connected with satellite internet (if in remote areas). Boom, you've just turned negative power prices into positive prices literally overnight.
Maybe such a cost saving gives them the additional capital they need to tackle the larger projects of hydrogen storage or transmission?