As far as gensets, fishing/tug boats, they would, as I understand, be a constant rpm.  No need to vary the hydrogen flow.  I've had a generator for years in my business and it has one running speed. But trucking, on the other hand, would have a varied rpm every time you changed gears, sped up or  slowed down.  Would be a question, perhaps, for jomama to take to HQ this month. Does telematics significantly increase the fuel mileage and how long before available?  My best to all,  Jim