Texas has its own electricity grid and is a very interesting case study. Read this piece on the economic benefits of integrating Solar PV into the Texas grid. This January, 2013 report insists that solar and wind power is now highly competitive with that derived from natural gas. Click on this piece, too. Note that, as of June, 2013, there is doubt about the Texas grid's ability to meet summer demand. (Source). But Austin, Texas now claims it's powered 35% by renewables.
"Texas accounts for about 14% of all the rural solar potential for the whole country. It also has about 20% of all the concentrated solar power potential for the nation. So, it appears this single, huge state could have a very bright future in terms of solar power development, and therefore in economic growth as well." (Source).
And San Antonio leads Texas in Solar with 34 megawatts (MW) of solar installed.
But cheap natural gas from fracking is altering Texas politics on renewable energy.