Fewer is better, but still not good enough. We need to change the practice of using diesel generators as a back-up power source NOW and then consider a variance.
It is past time for the data center industry to stop using diesel generators as a back-up power source even without a variance. There is far too high a concentration of data centers near homes and WAY too many more coming for the industry to continue this general practice, let alone allow those generators to be used even more extensively. Poor government planning has created a malaise of fear and loathing for this industry as citizens wonder if their homes will be the next ones inundated with industrial noise and toxic fumes.
It is in everyone's best interest, even the industry's, that the response be to heed citizens' calls to cease using diesel generators and move to a more sustainable and health-risk-free alternative and then you can have your variance. Stop solving corporate problems on the backs of citizens, and we will all get through this new industrial revolution of digital infrastructure more peacefully and with better relationship to industry.
Again, please don't set the precedent of allowing more diesel pollution during our worst air quality days and so near our homes. Put the onus on this billion dollar industry now instead of further burdening citizens with further health risks and even further diminished quality of life. The litmus test should be would you allow entire banks of diesel generators next to your home to run for extended periods of time while your kids played 100 feet away? If not, don't set that precedent for us.