The Register®

Original URL: http://www.theregister.co.uk/2012/06/22/wacky_power_stats/

Powering your iPad costs $1.36 per year

And other wacky stats from wooly electro-boffins

By Rik Myslewski in San Francisco

Posted in Hardware, 22nd June 2012 19:21 GMT

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If you charge your fully depleted iPad every other day, it'll cost you a buck thirty-six per year, according to a just-released study by the Electric Power Research Institute (EPRI [1]) of Palo Alto, California.

"At less than a penny per charge these findings bring new meaning to the adage, 'A penny for your thoughts'," said the EPRI's veep for power delivery and utilization Mark McGranaghan when announcing [2] the results.

We at The Reg are as fond of wacky stats as anyone, but this one – along with the EPRI's assertion that a quadrupling of iPad sales in two years would require the energy generated by three 250-megawatt power plants – is wackier than most.

Why exactly $1.36, for example? To their credit, the EPRI notes that "Costs may vary depending on what region that a consumer resides and the price of electricity in a particular location," but, as any reasonably savvy middle-schooler might say, "Well, duh..."

On more solid ground, perhaps, are the EPRI's claims that an iPad being fully charged every other day consumes under 12kWh per year, and that a 60-watt compact-fluorescent lightbulb eats up just a bit more power – about 14kWh – and costs $1.61 annually. But is that bulb burning 24/7? The oracle is silent.

EPRI also notes that 42-inch plasma-screen TVs suck up 358kWh during the same period – that's 358, not 357 or 359, mind you – and "laptop PCs" consume 72.3kWh annually, costing $8.31.

We contacted the EPRI to ask, among other things, just what they mean by "laptop PCs" – that is, do their figures represent, say, an entry-level Apple MacBook Air [3] or a tricked-out Alienware M18x [4] – but they hadn't responded by the time we clicked the Publish button for this article.

According to the report, an iPhone 3G's yearly 2.2kWh power will cost you a quarter per year. The EPRI doesn't provide figures for an iPhone 4 or 4S, however. Perhaps those models were sold out at the West Town Mall [5] Apple retail store in Knoxville, Tennessee, the town that's home to the EPRI's power utilization laboratory where the tests were conducted. ®