What a TDU actually is
In deregulated Texas, the company that sells you electricity is not the company that delivers it. Your Retail Electric Provider (REP) — Reliant, TXU, Gexa, Frontier, whoever — sells you the kWh. Your Transmission & Distribution Utility (TDU) owns the poles, wires, transformers, and smart meter at your house. They’re regulated monopolies; you don’t get to choose them.
Which TDU you have is determined by where you live:
- Oncor — DFW and most of North Texas
- CenterPoint — Houston and Gulf Coast
- AEP Texas Central — Corpus Christi and Lower Rio Grande Valley
- AEP Texas North — Abilene, San Angelo, West Texas
- TNMP — pockets across the state (parts of Galveston, Lewisville, Alvin, etc.)
When the Public Utility Commission of Texas (PUCT) approves a TDU’s rates, every REP in that zone passes them through on customer bills. They’re the same dollar amount whether you signed up with the cheapest REP or the most expensive.
The two charges on your bill
The TDU pass-through has two components, every month:
1. A fixed monthly customer charge.
A flat dollar amount that doesn’t change with usage. Currently around $3 to $5 in most zones. This covers the meter and the basic infrastructure to keep your service connected.
2. A volumetric delivery charge.
A per-kWh charge for every kilowatt-hour you consume. This is the part that scales with your bill. Rates vary by zone — Oncor sits around 4.6¢/kWh as of late 2025, CenterPoint around 4.8¢, AEP Central around 4.4¢, TNMP higher.
Some plans list these explicitly as separate line items. Many all-in or bundled plans roll them into the headline rate, which is why two plans advertising 12.5¢/kWh can actually be very different deals depending on whether the TDU charge is bundled or added.
How to spot it on your bill
Look for a section labeled TDU Delivery Charges, Delivery Charges, or your TDU’s name (e.g. Oncor Charges). You’ll typically see something like:
- Monthly customer charge: $3.42
- Delivery charge: 1,247 kWh × $0.04619 = $57.60
In this example, $61.02 of your bill went to the wires company, not your REP.
How to compare plans correctly
When you’re shopping, the EFL’s Average Price per kWh at 1000 kWh is the apples-to-apples number. It includes the TDU charge whether the plan bundles it or not. Compare those, not the marketing rate on the homepage.
If a plan brags about a 7.9¢ rate, scroll to the EFL and check the 1000 kWh price:
- If it jumps to ~13¢, the TDU is being added on top.
- If it stays close to 7.9¢, it’s already bundled — and you should be suspicious that something else (a high base charge, a usage credit cliff) is moving.
Why your delivery charge changed without you switching plans
TDU rates aren’t fixed forever. The PUCT approves rate adjustments — typically twice a year, in March and September — and TDUs file periodic rate cases that can reset the schedule. When that happens, your REP raises the pass-through portion of your bill mid-contract. Your energy rate stays locked; your delivery rate doesn’t.
This is legal and standard. It’s not your REP overcharging you. But it does mean a 12-month fixed plan is only partially fixed — the part of your bill the TDU controls can move under you.
The bottom line
TDU charges are roughly a third of a typical residential bill, and you can’t shop them away. What you can do:
- Know your TDU and its current per-kWh rate (it’s public on the PUCT site).
- Compare retail plans at the bundled 1000 kWh price on the EFL.
- Don’t blame your REP when the delivery line moves mid-contract — that’s a regulator decision, passed through.
- If you’re considering moving across town or to another metro, check the TDU change. Going from AEP Central to CenterPoint can mean a real bill difference even on the same plan.