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.
Once you sign up for your new energy plan, your local utility will be notified of the change and begin your service from the alternative supplier at the beginning of your next billing cycle. Upon starting your energy supply service, your utility company will include this charge on your energy bill and continue to charge for the delivery service portion of your bill. Why? Because although your supplier may offer you a competitive rate for electricity supply, your utility is still in charge of the infrastructure that delivers energy to your home – such as power lines and energy meters.