You could buy a pad mounted generator with a transfer switch and setup monitoring and maintenance contracts. You could even get a natural gas powered one if you

You could buy a pad mounted generator with a transfer switch and setup monitoring and maintenance contracts. You could even get a natural gas powered one if you have natural gas hookups, which means no messing around with diesel or gas. All of this will cost you significantly more than a portable gas generator, but with yearly maintenance and monitoring, most generators perform just fine. I work for an electrical contractor that is a General dealer, we do lots and lots of these.