8. Monitoring, Updates, and Review Timing
How the methodology is kept current.
Greenpixie maintains the methodology on a monthly refresh cycle. The scores are recomputed each month from refreshed copies of the input data, and each run writes one row for every combination of data version, provider, and region. No run partially updates a previous version, so every region in a version was scored against the same basket, the same grid period, and the same band boundaries, and the version number and the date of the run are carried in the page metadata of the published scorecard.
Provider price data is refreshed for every run. Grid carbon intensity factors are refreshed for every run, and each run averages the previous calendar month, so a region's figure moves with the seasonal generating mix as well as with capacity added or retired on a grid. The water stress category changes when the World Resources Institute republishes Aqueduct, on a cycle measured in years, or where a region's match to an Aqueduct area changes. The methodology team reviews a republication before it is adopted, as it can move the water stress category of many regions at once.
Greenpixie selects the comparison basket and sets the band boundaries again in every run, from that run's data. A region can therefore move from one grade to the next with no change to its own prices or its own grid, where a provider has launched or retired product categories in the basket, or where the distribution around the region has shifted. Carbon band boundaries are set across all three providers together, so a carbon grade can also move where regions belonging to another provider enter or leave the distribution. Every value on the scorecard is a band, so a version carries no underlying figure against which a grade change can be checked. Section 11.3 states the resulting interpretation rule.
Changes to a provider's published price list structure are found through the translation layer described in Section 5, as a change in field semantics normally presents as an unusual number of removed prices in the run that follows it.