Google: Our Green Data Centers Got a Lot Greener

I am responsible for some aspects of power and datacenter design where I work. What they're doing is really admirable (and hard), but they're going to do a lot more than many other, particularly smaller, datacenters simply because of their scale. From http://www.google.com/corporate/green/datacenters/measuring.... :

Figure 1 (chart showing aggregate 1.19 PUE, some as low as 1.1) summarizes the PUE results from all Google-designed data centers with an IT load of at least 5MW and time-in-operation of at least 6 months.

5MW is quite a bit of power. At a PUE of 2.0 that's 25000 amps (@100v), or about 8000-12000 idle servers. In Seattle, the breakover for the largest tier of power is 3MW, making 5MW about $194,000/mo (tariff 40) -> $0.053192 * (24365.25/12) 5000 = $194,283.

Obviously at these power levels being green is truly a matter of saving hundreds of thousands of dollars per month. It's a considerably tougher sell to justify high-efficiency construction in a small 100-200KW center, especially when colocating where cooling prices are obscured in the contracts under $/sq/ft instead of $/watt.

While this is nifty, the PUE figure they cite is a ratio of total datacenter energy consumed to total server energy consumed.

It's impressive what they have done to reduce the numerator, but it'd also be nice to see what they have done to reduce the denominator (even if that makes the headline PUE number worse in the short term).

I remember something from long ago about Google deploying it's own hardware to make the servers themselves more efficient. Anyone seen any updates on this? My google-fu must be weak.