The reason for this taxonomy is the same reason you use consts instead of plain numbers in computer code. You change the definition of “green” in just one place

The reason for this taxonomy is the same reason you use consts instead of plain numbers in computer code. You change the definition of “green” in just one place when someone invents a new loophole, or someone invents a new green method of obtaining sustainable hydrogen. Also, the descriptions would be too long in some cases. To be green, according to the new taxonomy, it’s not enough for hydrogen to be generated using renewables. It has to be generated by renewables built specifically for this purpose, and from water that is not drinking water - so that we don’t drain lakes and rivers to produce it. Now, gold hydrogen is just a marketing gimmick. It’s just brown or black, unless they store generated co2 safely and permamently - then it can become green.