A rotary engine would have relatively low output compared with the Coates engines. For that reason, I do not consider it to be a formable compeditor to Coates, even if it works. I am not an engineer but it seems to me that other factors like longivity and reliability would also play a big roll. I just can't see a rotary engine powering a large generator. Maybe a lawn mower or one of those roller skate cars but not a generator.