The fallacy of wireless power

Induction chargers promise convenience but use more power and take more space -- and they're not wireless

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Inductive charging wastes 30 percent of its power
Next, there's the power issue. Although induction chargers have become more energy-efficient, they still waste 30 percent of their power during transmission between the charging pad and the device's chargeable skin, as compared to wired USB chargers.

The Wireless Power Consortium's Treffer says that waste amounts to less than a penny per charge, but the environmental cost adds up: The average smartphone uses 5W to recharge, and there are more than 1 billion of them in use. Take the typical two-day charging cycle, and that's 900 billion watts of energy used. If those were induction chargers, the energy use would rise to 1.125 trillion watts, wasting 225 billion watts a year. Based on data from the California Energy Commission, that wasted energy would power 35,000 homes and produce 100,000 metric tons of carbon dioxide pollution each year. There'd be a similar proportion of wasted energy for tablets, cordless drills, and other devices for which induction charging is being proposed.

In the grand scheme of things, that wastage is small. Today's power chargers waste 60 to 100 times as much power as using induction charging would. That's because most of today's chargers use power even when not charging ("vampire power"), burning off energy for no reason all day, every day. The Qi standard doesn't require chargers to shut off when not in use, but it doesn't preclude manufacturers from doing the right thing by implementing auto-shut-off technology.

The wasted power in induction chargers is real, but tiny compared to all the other energy wastage for battery-charged devices. Still, in an era where greenhouse gas emissions and environment degradation are causing destructive climate change, it's offensive to promote products that waste energy. I urge the Wireless Power Consortium to make auto-shut-off a required part of the standard, and for the European Union to require all chargers to have that feature.

Why the E.U.? The U.S. government is too averse to regulation to require it. California is looking to impose wireless charger efficiency requirements that could help because manufacturers typically use its standard across the United States rather than make two versions, but the E.U. is a more powerful force for change: When the E.U. mandated the end of proprietary phone chargers a few years ago to reduce unnecessary electronic waste, the result was a quick change to standard USB chargers worldwide, reducing waste globally and simplifying usage for consumers at the same time.

Inductive charging's minor benefits may yet prevail
Although I don't believe the imperative for inductive charging is that strong, the barriers to its usage are also not strong. At $75, an inductive power mat is affordable to most business professionals and could get cheaper over time. The barrier to entry is fairly small -- especially if your smartphone or tablet happens to support the technology out of the box. At worse, you stop using the mat because it's always buried in papers; at best, you develop the habit for unconsciously placing your phone in the right position and leave your charging cables in your travel kit.

If inductive charging does become common, I suspect it will be a slow burn -- at an uptake rate commensurate with its marginal benefit.

This article, "The fallacy of wireless power," was originally published at Read more of Galen Gruman's Mobile Edge blog and follow the latest developments in mobile technology at Follow Galen's mobile musings on Twitter at MobileGalen. For the latest business technology news, follow on Twitter.

Copyright © 2012 IDG Communications, Inc.

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