Do they already have a heater control system in each unit? Would it cope if so? If not - then this is completely dumb, we have a weak link for abundant power - just because it got cold.
There are turbines all over Iowa, Illinois, and the upper Midwest and they don’t freeze up like this, so evidently there are design differences.
Up in the Dakotas they use grid power to heat the oil, but it is unlikely they have adequate heaters in TX.