When the United States rolled out the first electrical grid, light bulb filaments were quite fragile and burned out fast on 220-volt lines. Dropping the voltage to 110/120 volts increased filament life -- thus, the U.S. standard of 120 volts. By the time Europe and the rest of the world built out their power grids, advances in filament design had largely eliminated the high-voltage problem, hence the 208/220-volt power systems across most of the rest of the globe.
What’s important to note is that each time voltage is stepped down, a transformer is used, and power is lost. The loss may be as little as 1 percent or 2 percent per transformer, but over time and across a large datacenter, the penalty for transformer use adds up. By switching to a 208-volt system, you need one less transformer in the chain, thereby reducing wasted energy. Moreover, 208/220-volt systems are safer and more efficient; more current is required to push the same wattage through 120 volts than 208/220, increasing the risk of injury and losing additional power in transit.
For those considering capitalizing on the switch, rest assured that nearly all server, router, and switch power supplies can handle 120- or 208-volt power and most are auto-switching, meaning no modifications are necessary to transfer that gear to 208 volts. Of course, the benefits of 208-volt power in the datacenter are not the kind to cause a sea change. But as energy costs continue to rise, the switch to 208 volts will become increasingly attractive.
Retrofit for advantage
When it comes to budgeting for the datacenter, most line items can be forecasted. Determining the cost of hardware to build and maintain the room is relatively easy. The costs of providing power to all those systems tends to sway in the breeze, however, and even a small jump in the unit price of power can put a big mark on an otherwise pristine balance sheet.
And where there is variable cost, there is the potential for competitive advantage.
Virtualized servers, localized cooling solutions, and cost-conscious means of delivering power to the server room are changing the underlying principle of database design to a search for greater energy efficiency. The killing-flies-with-a-shotgun approach to cooling and powering the datacenter has been banished to the history books along with the 85-cent gallon of gas. Retrofitting existing datacenters is never easy or inexpensive, but in this case, the benefits are immediate.