ESI ID: what it is and how a Texas business finds it

What an ESI ID is.

The Public Utility Commission of Texas defines it as the basic identifier assigned to each point of delivery, used in the registration and settlement systems that run the state’s competitive electricity market (Substantive Rule 25.5(41)). Your utility, such as Oncor or CenterPoint, assigns it when the service point is set up.

It is not your account number. CenterPoint says so in capitals on its own site, and TNMP points out that it differs from the account number with the company that bills you. The account belongs to you and your provider; the ESI ID belongs to the location. AEP Texas’s tariff describes it as a unique, permanent number, which is why it stays the same when a business changes supplier or a new tenant moves in.

What it looks like.

An ESI ID is all digits. Its length and opening digits depend on the utility that delivers power to the address:

Oncor’s IDs are a common 10-digit prefix followed by a 7-digit number unique to the service address. If your number is a different length from the one in the table, you are probably looking at the account number or the meter number instead.

Where it is on your bill.

Every retail electricity bill in Texas must include “the service address, electric service identifier (ESI), and account number of the customer” (Substantive Rule 25.479(c)(1)(D)). Look for it near the service address; it may be labelled ESI ID, ESIID or ESI.

The rule covers bills from retail electric providers. A business served by a municipal utility or a cooperative that has not opened to competition, such as Austin Energy or CPS Energy, buys from that utility and cannot switch supplier. Our guide to reading a business electricity bill walks through the other lines.

Finding it without a bill.

• Oncor: its ESI ID lookup searches by ZIP code and street address.
• TNMP: call 888-866-7456, Monday to Friday, 8:30 a.m. to 7 p.m. Central.
• CenterPoint: we found no public lookup for an existing address on its site. CenterPoint creates ESI IDs for new service on 713-207-2222; for an existing site, use a bill or ask your current provider.
• AEP Texas: its address search is for retail electric providers, so ask your current provider.

Your current provider always has it: it is printed on every bill they send you. If you take over a site, the ESI ID stays with the address, so the previous occupant’s bill shows the same number.

Several sites, several ESI IDs.

Each point of delivery usually has its own ESI ID. AEP Texas’s tariff requires a unique ESI ID for each point of delivery, and TNMP says every meter location has one. So a restaurant group with five locations normally has at least five, and one site can have more than one if a separate building, a sign or a construction pole is metered on its own. The reverse also happens: CenterPoint can assign a single ESI ID to a combination of delivery points at one premises.

For a business with several sites, keep one row per ESI ID: the service address, the ESI ID, the supplier, the contract end date and who receives the bill. It is the list a supplier needs to price the group, and it stops two sites with similar addresses being confused. Our contract renewal guide shows how to track the end dates.

Why a supplier asks for it.

The ESI ID is how the market knows which meter a contract applies to. When a business chooses a new provider, the provider must obtain or confirm the ESI ID where it is available (Substantive Rule 25.474) and sends the switch to the market’s registration agent, which tells the utility to make the change. AEP Texas describes it as the key identifier providers use for switches and move-ins.

It matters before then too. A supplier prices the actual meter: its usage history, its demand and its delivery area. That is why a firm price needs every page of a recent bill, ESI ID included, for each location. Start with your business ZIP and email, and add the bills when you have them.