fyi all current hydrogen plants use either a mix with 50-70% gas or 100% hydrogen but are creating huge NOx as byproduct due to high temp burning. That's just one of the many hydrogen challenges, another one is H2 handling is harder, another one is the more renewables you get, the more your H2 plants would cost since in some periods you use them extensively, in others - very little and to compensate such infra cost&maintenance the plant owners will jack up the prices or seek govt price compensation. That's why many say hydrogen plants/energy is somewhat of a pipedream