New Data Center Strategies Newsletter, Network World, By Andreas M. Antonopoulos, Network World, 10/10/06

Of every kilowatt of power entering your data center, less than 30% will do any actual “work” for you. The rest will be lost to inefficiencies in power supplies, UPSs and inside servers. And despite the recent drop in energy prices, with China’s demand for power and the tight energy market in North America, electricity is likely to be a major cost in data centers for many years to come.

Data center managers and companies with large server farms are taking steps to increase energy efficiency as a way to save money on utility bills. Google, with one of the world’s largest server farms (estimated at around 500,000 servers) is leading the pack.

Over the last couple of years, Google has reportedly refined its server design, increasing power efficiency and reducing its electric bill. While most servers lose 30% to 40% of input power due to inefficiencies in the power supply, Google has reached efficiencies of 90% on its servers.

Based on this experience, Google is now lobbying for changes in server design.

Today’s servers have power supplies that convert utility power (110V AC) to DC power at 3V, 5V and 12V. Google’s proposed design is much simpler, with a single conversion to 12V, which is then further converted to other voltages by the motherboard. The simpler design of such a power supply can lead to much greater efficiency in the voltage conversion, reducing heat output and power loss.

Another interesting side effect of such a design is that it would make it much easier to deliver 12V DC directly to the server, bypassing the power supply and standardizing all data center power to 12V DC. There are some drawbacks to DC power to the rack, such as the need for thicker cables. But, 12V DC to the rack enables simpler power distribution units, uninterruptible power supplies and batteries - all of which can increase efficiency and reduce costs.

A similar transformation in data center power is coming from another source entirely: voice and data convergence. As companies deploy converged voice/data networks and IP telephony, a key risk is the loss of power to the individual phones. Therefore, companies may deploy Power over Ethernet (PoE) to each phone in order to increase availability. As more switches are designed to deliver PoE, DC power gains even more prominence in the data center and wiring/telecom closet: Now DC can be used for servers and distributed over Ethernet to other parts of the infrastructure such as phones, Webcams and wireless access points.

The world will have to deal with high energy costs for many years to come. Data centers are already feeling the pain, with electricity bills becoming a big part of the overall cost of ownership. As cheap energy leads to waste and inefficiency, expensive energy is driving innovation in every part of the power distribution chain. In a few years, wasteful servers may be as rare as muscle cars in an oil crisis.