Technical Information

Green Button technology allows data to be exchanged between Utilities, Customers, and Service Providers.  The NAESB REQ.21 ESPI standard refers to these entities as Data Custodians, Retail Customers, and Third Parties; respectively.

The following section provides a definition of these actors and other Green Button terms:


Retail Customer

Any individual or enterprise that receives electricity, gas, or water services from a Data Custodian.  Retail Customers include residential, commercial, or industrial account holders.


Data Custodian

Any enterprise that holds Retail Customer Energy Usage Information, typically acquired from a meter, during the course of providing electricity, gas, or water service to a Retail Customer.  A Data Custodian holds Energy Usage and Retail Customer Information as part of the service they provide and may, with the authorization of the Retail Customer, share that data with a Third Party.  A Data Custodian may be a Distribution Company.


Third Party

Any individual or enterprise authorized by a Retail Customer to access the Retail Customer's metered or Personal data held by a Data Custodian for the purpose of providing some service to the Retail Customer.  A Third Party, authorized to access a Retail Customer's data, may create a subscription with the Data Custodian holding the data only for the purpose of providing additional services to the Retail Customer. The Retail Customer may modify or revoke authorization for a Third Party to access their metered and personal data at any time.


Energy Services Provider Interface

A standardized machine-to-machine interface that permits a Data Custodian to share, at the Retail Customer's request or direction, a broad set of that Retail Customer's Energy Usage or Retail Customer Information held by that Data Custodian with Authorized Third Parties.  It is the “ESPI” name of the NAESB REQ.21 ESPI standard.


Energy Usage Information

Any information from a metering device identifiable to an individual Retail Customer concerning that Retail Customer's energy usage.


Retail Customer Information

Any information, typically account based, used to identify an individual Retail Customer.


Authorized Third Party

A Third Party that is permitted to receive Energy Usage Information utilizing the Energy Services Provider Interface, who has met the requirements of the Applicable Regulatory Authority and Governing Documents.


Relationships Between the Actors

The actors enter into relationships as depicted in the diagram, below:  

Relationship triangle of Data Custodian, Retail Customer, and Third-Party Service Provider.
Green Button Relationship Triangle



The simplest relationship is the one that exists between the Data Custodian and the Retail Customer.  This relationship allows the Retail Customer to download one or more files that contain their Energy Usage Information or their Retail Customer Information.

This simple one-to-one relationship is the basis for the Green Button Download My Data (DMD) method.


A more-complex relationship, but one with fewer ongoing requirements of a Retail Customer, is the one that exists as a triangle between the Data Custodian, the Retail Customer, and the Third Party.  This relationship allows the Retail Customer to authorize the Third Party to obtain the needed data on behalf of the Customer, directly from the Data Custodian.

This triangular relationship is the basis for the Green Button Connect My Data (CMD) method.