Is hydrogen a good fuel for back-up generators?
It's impossible make a 100% leak proof container for hydrogen and it will embrittle many materials including stainless steel.
There does not seem to be a good fiscal reason for this, it'll have higher purchase and running costs than a diesel or gas generator so the only reason to go this way is either if it is subsidised or good old fashioned green-washing. (Which doesn't work because there is only a tiny amount of "green hydrogen" available now and for the foreseeable future),