What .41 cents will buy you these days..

Spare change, anyone? That's all it costs to charge your smartphone for a year.

The iPhone 5 requires a mere 41 cents annually to juice up once a day, and the Samsung Galaxy S III just 53 cents (due to a bigger battery), according to new research by Opower Lab.

The team has compiled a lengthy analysis of the pocket-digital revolution's impact on energy use. While a lot of the study is head-spinning, the takeaway is this: the new cell phones are cheap to keep running.

Other gadgets seem like electricity hogs by comparison. iPads, for example, have been found to cost $1.36 a year to keep charged; desktop computers have been found to cost $43.60 per year.

But smartphones are multiplying so quickly that the consumption is adding up. The projected amount of iPhone 5s to be bought in a year will use as much power as 54,000 U.S. households, which is "roughly equivalent to the size of Cedar Rapids – the second largest city in Iowa," per Opower Lab. And all this says nothing of the energy required to process all the data we're accessing with increased frequency on our handheld doo-dads.

Click here for more (way more) details from Opower's report.