It’s likely some customer segmentation label generated through PCA or some other clustering approach.

The qualifying criteria is probably just having picked an offer for renewable-sourced energy in the past, indicating that it has some importance to you. So you will be given more green energy offers in future.

Every company segments its customer base this way for marketing. Sometimes it’s even useful.

They probably don't care. It's probably a mostly BS number. But they probably have to have it and have it at least look like they're trying to be serious about generating it in order to qualify for preferential treatment on some sort of permitting or write off some class of investment in a slightly better way at tax time or something.

I'm not sure if this is better or worse than them doing it because they believe in it.