Tony Duncan suggests that Texas can run off solar electricity. Let’s do the math.
Texas is averaging about 55 Gigawatts of electrical consumption today. Averaged out over 24 hours, a cloudless summer day might achieve 200 watts / m² solar insolation. The most efficient solar collectors are about 15%.
55,000,000,000 / (200 * 0.15) = 1,830,000,000
It would require almost two billion 1 m² solar panels to meet the average consumption today – assuming that you had a currently non-existent technology to store the electricity at night.
Now assume you got an outrageously good deal on the solar panels and only had to pay $100/m² – that would cost $200,000,000,000 for the panels and maybe that much again for the installation and power lines.
And of course it won’t work very well when it is winter, cloudy, dusty or at night.