The modern data center guarantees uptime to the customer. They design for this, it is what they get paid to provide.  A generic design model calls for dual sources of water for cooling(2 sources of water entering via separate pipes by separate companies or sources). Duals power lines for electricity, from alternate sources. Generator backup in case of widespread power outage. These generators are on site and routinely tested. They are not procured when they receive notice of an outage. Data center providers are trying to reduce the cost of doing business by advocating tier 2 “dirty generators”. This should not be allowed. If the data center operators want to offer their customers a high level of data center uptime, they should pay for the installation of tier 4 generators. Another option is for the data center to fail the services being provided on a data centers servers over to another data center located in an area not impacted by a planned outage. Very expensive but offered by many data center providers. In an emergency they may need to run their generators, I have no issue with this model, I do object them doing so at the cost of the quality of air I breathe.