A green light is one that's never on

Stuart Corner
Friday, 30 May 2008 07:15

Opinion and Analysis

Go into any data centre and you will see thousands of tiny lights, in the rows and rows of electronic gear. A UK company reckons these, and those on computing equipment in UK homes contribute 50,000 tonnes to CO2 emissions and waste £10m a year in energy costs.

Not only are these things wasting energy and cash, LS Simple draws a very long bow suggesting that "the wasted energy could ultimately pose a threat to continuing data centre operations, and even business survival." Exactly how is not explained.

This is really drawing a long bow, when as Paul E, regional manager Europe of LS Simple, points out "With many data centres consuming hundreds of Megawatts of power, the LED power consumption is a tiny fraction.

It would be totally unrealistic to open up every one of these boxes and turn of the offending LEDs (and indeed some of them perform important functions indicating the state of the equipment). But LS Simple isn't seriously suggesting we should. What it is really trying to do is sell its intelligent power management technology, pointing out that "when intelligent power management is deployed, Data Centre operations can often save 30 percent of their consumed power." And all without turning off a single LED!

And if you want to know how LS Simple came up with its 50,000 tonne figure for LEDs, here's how.  It assumes a power consumption of 0.3 watts per LED, that they operate at a 60 percent duty cycle (ie when flashing are on for 60 percent of the time - but what about the many LEDs that are on all the time?). It further assumes that UK data centres have 10,000 racks of equipment with 210 LEDs per rack. And it assumes that generating one kilowatt hour of electricity releases 0.5kg of CO2 into the atmosphere.

Do the maths and this gives a figure for data centre LEDs of almost £3m in electricity costs and 17,000 tonnes of CO2. LS Simple then assumes that "There must be at least twice this number of LEDs in PC boxes, screens and printers in homes and offices around the UK." Hence three times the power and CO2 that is calculated for data centres alone.

It all sounds quite 'simple'. Turning off the LEDs wouldn't be. And despite many vendors touting their green credentials and the myriad ways they are cutting power consumption in their equipment I have not heard one boast about having fewer flashing lights. So I reckon this one's a furphy. But it did get them noticed.