Your landlord cannot shut your power off. He can, however, evict you for nonpayment of rent and this would be the legal route to go if a tenant does not pay rent. Paying the money "when you get it" is a bit vague. It would be better to come up with a more suitable payment schedule for the landlord.
And if you bring up the issue of the garage not passing code to enforcement you will likely have to move anyway. The converted garage business hasn't seemed to bother you for the past two years.
Gail

