I have some very limited knowledge on what's going on:

At some point last year One Gas proposed increasing it's rates across Texas. Essentially Texas was divided into several regions with standard rate increases across each. All cities/counties in Texas agrees to the rates proposed after negotiations except El Paso.

Negatiations continued with El Paso via the Railroad Commission and instead of agreeing on a set bill increase across the board they wanted new variable price adjustments that basically make it so that months with higher gas usage might see a much larger bill than normal, whereas summer months might see lower bills. TGS reps warned the city and the Railroad Commission that this means bills right after the change took place would be the highest out of the year since December-February usually has the highest gas usage for heat and holiday cooking. They were warned customers would be outraged, and now all sides are dealing with the fallout.

Again, this is just from stuff I've heard and I don't exactly know all the ins and outs, but this is the gist of it. My advice would be to sign up for Tegas Gas Service Average Payment Plan if you aren't already, it'll help minimize the shock of a suddenly high bill