Data centers should be required to have backup generators that cause the least amount of environmental impact. Diesel generators do not fit this parameter and should not be authorized.
A great deal of these centers have a ridiculous carbon footprint as it is. Wildlife habitats are shrinking. Their water usage is high. Their impact on the electrical grid is also high, and I've already witnessed an increased number of power hiccups and brownouts just in my day-to-day existence in Virginia.
Allowing data centers to use diesel generators when they're almost guaranteed to have to use them due to their own drain on our grid is not acceptable. This further puts the environmental and public health costs of these monstrosities on the everyday citizens who have to live and breathe nearby.