This is why I was hoping that someone could explain the technicalities of the U.S. energy system to me – can't we simply ask our datacenter providers to order renewable energy for our servers, maybe for an extra charge? This is what you can do in Europe, but I have a feeling things are not just as easy in the U.S.
In the U.S., electrical utilities are mostly regulated at the state level, not the federal level. There is no federal renewable energy policy (AFAIK), but over half of the states in the U.S. have a renewable portfolio standard requiring utility companies to supply some percentage of their electricity from renewable sources. In addition, some utility companies in the U.S. let consumers purchase "green energy" at a higher price. So basically, you would need to investigate the policies of the specific electricity companies used by the datacenters as well as the policies of the states they reside in.