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April 27. 2013 10:56PM

Sam Asano's Let's Invent: Stopping phantom power load waste


Editor's note: Sam Asano's column on inventing debuted in the Portsmouth Herald earlier this year. We are publishing his collected columns in sequence in the Sunday and Monday business sections over the next several weeks after which the new columns will appear on Mondays.

The term "phantom power" (also called phantom loads, vampire loads) is defined as the power wasted in various household and commercial appliances while they are not actively used for the purpose they are designed for. Pre-1970s, most of such devices and appliances were simply switched on for use, and off when the task was finished. Therefore, the amount of phantom power waste was next to nothing in this country.

In the decades starting from late 1970s to the present, three devices began to cause a massive rise in the phantom power waste: cell phones, laptop computers and TV set-top boxes.

Of all three, cell phones are the worst offender due to sheer numbers, and the TV set-top boxes are the highest in power consumption, even though there are no more than a few per household.

Let's take the cell phone. It consumes relatively small wattage while it is being charged. However, the small innocuous AC charger plugged into the wall socket is rarely unplugged when it is unneeded. I know I don't unplug them (I have three in my house and one in my office), and they are constantly consuming electrical energy even though the amount is small. However, multiplied by the sheer number of the cell phones in this country, or for that matter in the world, the phantom consumption does become a serious issue.

According to a report from Lawrence Berkeley National Laboratory, roughly 10 percent of household electrical consumption is due to the phantom loads of various appliances. The average U.S. household spends $100 per year to power devices while they are off (or in standby mode). On a national basis, standby power accounts for more than 100 billion kilowatt hours of annual U.S. electricity consumption and more than $10 billion in annual energy costs.

This corresponds to about 1 percent of the world's CO2 emissions. As someone once said, "$10 billion here and $10 billion there, pretty soon that gets to be serious money." Well, not only that, all that energy does become heat in the end, and contributes to global warming.

What shall we do to reduce or eliminate the phantom loads? There have been many attempts to develop, manufacture and market such devices. However, all such implements measure the current consumed in the device (load) connected to it, and reduce its own consumption accordingly. That means the control device has to be alive and consuming electricity while the load is either reduced or off. This is a logic conundrum, if you see what I mean.

What we want to do is to cut the power to the power supply when it is not providing the power to, say, a cell phone. But to do that, it needs to consume a small amount of power to keep itself alive. See Fig. 1 of Case 1305.

Fig. 1A shows you today's device, which needs electricity to keep itself alive while consuming less electricity. Fig. 1B is the ideal picture, where the control device is completely disconnected to the power line when the load is not connected to it.

I receive many suggestions, solutions and arguments via e-mail these days. I find that readers are quite good thinkers. Many of them excel beyond the professional level. So I have a big challenge for you all. Can we solve this problem? Can we disconnect the control device completely from the power line when it is still plugged into an AC outlet, but its load is disconnected?

Send your suggestions, solutions and discussions to Let's invent.

Shintaro (Sam) Asano of New Castle, who speaks and writes English as a second language, was named by MIT in 2011 as one of the 10 most influential inventors of the 20th century who improved our life. He is a businessman and an inventor in the field of electronics and mechanical systems, who is credited as the original inventor of today's portable fax machine. He also developed a data tablet used in the retail point of sale to capture customer signatures when credit cards are used. Write to him at