How about the mines and aluminium smelters?
different economics ...
those industries are inclined to demand high quantity on site at a low price
I imagine NOs are paying the municipal rate for the bulk of their electricity and need a multisite approach.
Note I am not suggesting that NOs should replicate a national grid but rather that they should produce their own electricity requirements and feed in and off at a zero base - if they produce more than they need they should feed in at the higher rather than lower tariff