The entire data centre runs off solar, so that includes the servers, cooling systems, office stuff, the works. There's plenty of details on our website about the
data centre and
the network.
As for the backup generator, it's not really any different to the backup generators that all web hosts will (or should) have in place in case their mains power goes down, other than it's a propane powered gennies rather then diesel. Our reasoning being that out of all the carbon based fuels, it's one of the less polluting and more efficient, plus if there was ever to be a fuel spillage, it has less potential for causing major damage to groundwater, etc.