Too bad Texas isn't hooked up to the national grid. They could be getting power from Oklahoma and Kansas.
North Dakota and South Dakota get more of their power from wind than Oklahoma and ND has the lowest rates in the country. Oklahoma has lower rates than Texas according to your source and some of the lowest in the country. The problem Texas seems to have is they don't know how to plan for anything like cold or heat. It's almost like they have never heard of those things.
ND gets most of it's electricity from natural gas, oil, and coal.
OK gets most of it's electricity from natural gas, oil, and coal as well.
TX handles hot weather just fine. They handle cold weather reasonably well.
Wind generators do not work in icing conditions.