This is one area where going green and saving money diverge. The cheapest renewable tariffs tend to cost more than the cheapest standard tariffs, so it really is a question of your personal politics. However, if you can afford to go renewable, then it's a help to the environment, and all the main comparison services allow you to compare renewable tariffs.
There are over 60 different energy suppliers competing for your business on any given day in Texas. Many of these electric companies have websites that are confusing and nearly impossible to navigate, their rates and fees hidden by dense industry jargon and misleading advertising. Who has the spare the time to sort through the choices spread out over all these different sites and companies?