An ESI ID number, short for Electric Service Identifier, is the unique code the Electric Reliability Council of Texas (ERCOT) assigns to every electricity connection point in the state’s deregulated areas.1Cornell Law Institute. 16 Texas Administrative Code 25.5 – Definitions It’s attached to a physical address, not to you and not to your meter, so it stays the same when you swap meters or change electricity providers. You’ll need it any time you set up service, switch retail providers, or register for online usage data.
How to Find Your ESI ID
Your monthly electricity bill is the quickest place to look. The ESI ID is printed alongside your account details, usually as a long string of digits starting with “10.”
If you don’t have a bill, your utility can look it up by address. Oncor offers a free online ESI ID lookup tool on its website, which is especially useful when you’re moving into a new home and haven’t been billed yet.2Oncor. ESI ID Lookup You can also call your retail electric provider and ask, though you’ll need to verify your identity and service address first.
What the Number Looks Like
Every ESI ID begins with “10,” which flags it as an ERCOT identifier. The next several digits identify your Transmission and Distribution Service Provider (TDSP), the utility that owns the poles and wires serving your home. The remaining digits are unique to your property.
Length depends on the utility. Oncor, AEP Texas, and Texas-New Mexico Power use a 17-digit format. CenterPoint Energy, which serves the Houston area, uses 22 digits.3CenterPoint Energy. CenterPoint Energy Houston Electric LLC ESI ID Format The opening digit sequence also tells you which utility you’re on: 1044372 is Oncor, 1008901 is CenterPoint, and 1003278 or 1020404 is AEP Texas.
When You’ll Need It
Because Texas lets customers in deregulated areas choose among competing retail electric providers (REPs), the ESI ID is what links your chosen provider to your specific address in ERCOT’s system. Only one REP can be assigned to an ESI ID at a time.1Cornell Law Institute. 16 Texas Administrative Code 25.5 – Definitions You’ll be asked for the number in a handful of situations:
- Switching providers. Your new REP uses the ESI ID to request the transfer in ERCOT’s system. A wrong number means the switch stalls or lands on the wrong address.
- Starting service at a new address. Your provider uses it to connect your account to the correct meter point.2Oncor. ESI ID Lookup
- Reporting a power outage. The ESI ID pinpoints the exact connection point affected.
- Registering with Smart Meter Texas, the state’s portal for near-real-time usage data.
Whether the Number Changes
For a given address, the ESI ID is meant to be permanent. Replacing or upgrading your meter doesn’t change it. Switching retail providers doesn’t change it. If the property is sold, the number stays with the location.
The exception is when the utility creates a new service point: a property gets subdivided, a building is demolished and rebuilt with a different electrical configuration, or a brand-new connection is installed. In those cases a new ESI ID is assigned. For most homeowners and renters, the number on your first bill is the one that will stay tied to that address for as long as the connection exists.
Fixing an ESI ID Mismatch
The usual problem is just not knowing the number, which the bill and lookup tools solve. A trickier issue is a mismatch, where your provider’s records don’t line up with ERCOT’s. This can follow construction work, a meter replacement that wasn’t logged correctly, or a data entry error during a provider switch.
If your bills look wrong, a provider switch has stalled, or your Smart Meter Texas account is showing data that doesn’t match your home, ask your retail provider to confirm that the ESI ID on your account matches the one ERCOT has for your address. Your TDSP utility (Oncor, CenterPoint, AEP Texas, or TNMP) is the entity that actually assigns and manages ESI IDs, so for a persistent discrepancy your REP may need to coordinate with the utility to correct the record.