TDU Delivery Charge: TDU stands for transmission and delivery utility — in other words, the utility company in your area that is actually piping the energy from the power generation companies into your home. (Remember, REPs in Texas are just the middleman.) The TDU delivery charge is set by the utility and is consistent from plan to plan and provider to provider within its service areas. For example, AEP , the TDU for Corpus Christi, charges the same delivery fee for all TXU, Direct Energy, and Reliant plans. You don't typically get a choice in utility company, and therefore, these fees are pretty much unavoidable, non-negotiable, and won't factor into choosing an electricity plan or provider.
In this free market competing electricity retailers buy electricity wholesale from private power generators to sell at retail to around 85% of Texas residents. The partnership between generators and retailers is governed by the Electric Reliability Council of Texas, or ERCOT, which attempts to balance the power grid’s electricity supply and demand by purchasing small amounts of electricity at 15-minute intervals throughout the day.