The GIS Operating Rules Section 2.1(b) describes the ability for a generator that has missed the deadline to report meter data to the NEPOOL GIS in that it can report and have its certificates issued the next succeeding calendar quarter.
For NON generators, it is up to the purchasers of the Certificates as to whether they want any assurances about when the generation occurred and up to the regulators as to whether to count those Certificates.
Please reach out to the State Regulators to review this request and confirm if prior years generation data can be used for the current trading year's RPS compliance.