Purchase the Standard

Purchasing the ESPI Standard

The Green Button® Certification tests require the applicant to comply with the North American Energy Standards Board (NAESB) copyright policy.  This requires that all implementers of the NAESB REQ.21 Energy Services Provider Interface (ESPI) standard (commonly called Green Button®) undergoing testing must have purchased the latest standard version, NAESB REQ.21 ESPI ver 3.3, or have received it as a benefit of NAESB membership.

To determine if a Certification Candidate has purchased the standard, the Test Administrator will access the NAESB Purchased Standards (PDF) document and search for the Candidate’s company name.

Obtaining the Latest Version of the Standard

Version 3.3 is the latest version of the standard.

In 2019, NAESB ratified enhancements to the standard, which was published in 2020, and included the following changes:

  • Replaced OAuth 1.0 with OAuth 2.0 for Confidential Clients
  • Updated security requirements to TLS 1.2 as a minimum
  • Revised the Energy Usage Information (EUI) data structure and definitions
  • Created the Retail Customer (PII) data structure and definitions
  • Deprecated original Use Cases that do not meet OAuth 2.0 data security requirements
  • Added Use Case for Download My Data (DMD)
  • Simplified Use Case 2: Customer Authorization process
  • Documented Standard ESPI Application Program Interface (API) formats


Order a copy of the standard here (PDF):