But even that assumes all the IT load will be for servers. Certainly there will be power going to servers, network switches, etc., so the total would be lower than that. And if the NSA is using any larger servers (which considering its history, it most likely is), the number could be substantially lower than that. The average power consumption for a TOP10 supercomputer in 2008, for example, is about 1.3 megawatts, which in itself equals 2,600 500-watt servers.
IBM has a colossal claim to the mainframe marketplace, and can largely dole out its own terms to customers. When another business starts using IBM's own hardware to compete, IBM has a tendency to roll up its sleeves.