Google now supports Certification markup support for merchant listings in the product structured data documentation. Google wrote, "starting in April 2025, we're replacing the EnergyConsumptionDetails type with the more robust Certification type, as the new type supports more countries and a broader scope of certifications."
There are now 40 references in the product structured data documentation around certifications with many code examples.
Google posted in the documentation:
Upcoming change: The EnergyConsumptionDetails type is being replaced by the Certification type in April 2025. To specify an energy efficiency class, use the Certification type instead. If you have EnergyConsumptionDetails types on your site, we recommend that you switch to using the Certification type by April 2025.
There is a new recommended property "hasCertification" which Certifications, such as energy efficiency ratings, associated with a product. Up to 10 certifications can be specified. This property is particularly relevant in European countries. See also the list of Certification properties supported by Google.
Schema.org has the full definition of Certification schema if you want it:
A Certification is an official and authoritative statement about a subject, for example a product, service, person, or organization. A certification is typically issued by an indendent certification body, for example a professional organization or government. It formally attests certain characteristics about the subject, for example Organizations can be ISO certified, Food products can be certified Organic or Vegan, a Person can be a certified professional, a Place can be certified for food processing. There are certifications for many domains: regulatory, organizational, recycling, food, efficiency, educational, ecological, etc. A certification is a form of credential, as are accreditations and licenses. Mapped from the gs1:CertificationDetails class in the GS1 Web Vocabulary.
Google has their definition and support case over here:
The following examples illustrate how to specify certification information using structured data. The first example specifies the German CO2 emissions class "D" for a vehicle:
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