Convenience vs. Efficiency, Guess Who Wins?

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A year and a half ago, I wrote how Starbucks, early adopter and therefore, through its ubiquitous locations and preferred venue for professionals to work, a driver of adoption of WiFi, was driving adoption of "wireless" charging. Unfortunately, unlike WiFi, it wasn't truly wireless, "anywhere within a reasonable range" charging, but rather more like "plugless" or "contactless" charging, using PowerMatters Aliance (PMA) mats built into their tables. Put your phone on the table and it charges.

In the last year or so, significant advances have been made in the effort to create truly wireless, "anywhere within reasonable range" charging. The net result, if successful, would be to "pick up" power to charge our devices anywhere within range of a base station, just as we "pick up" data to connect to networks and the Internet anytime we are within range of a WiFi access point.

uBeam has made a lot of headlines recently, due not only to its products, but also due to the backing of some very serious players, including Marc Andreessen, Mark Suster, Tony Hsieh and Marissa Mayer. In the meantime, Energous's WattUp made a splash at CES. Both of these use different technologies - uBeam with ultrasound, Energous with RF - but the concepts are the same.

In a conversation earlier this week with an investor who has a lot of experience in the energy space, he said that these companies have an efficiency issue. And he is right. Every medium loses energy over transmission. This is as true for gold connectors as copper wires as even fibre as trying to send electricity of data through a piece of rubber or plastic. Everything loses energy as the signal travels through it, which is why we have repeaters and limits on cable length. The question always is, how much will a medium lose?

Unfortunately, air is not a particularly good transmitter of signals.

  • Unshielded interference
  • Lots of different particles
  • Varieties of humidity, temperature and matter

Certainly, air is not as bad as trying to send a signal through silicone oven mitts, but it is far worse than a traditional copper cable. Cables are designed and manufactured to exacting standards. The metal along which the signals travel have a precise makeup to optimize conductivity and minimize signal loss. They are shielded, not only to prevent your electrocution, in the case of power cables, but also to keep leakage to the minimum possible.

Air has none of these benefits. As such, the maximum theoretical efficiency of a true wireless distribution system cannot exceed 70%, and is unlikely to be much better than 50% in a good situation.

To which I say, "so what?"

It most certainly takes more power to transmit your Internet signal wirelessly around the house than it does to connect everyone with some Cat5 or Cat6 Ethernet cables... and yet just about every home and office has WiFi routers.

It will take a lot more power to transmit, well, power to your phone and table, and eventually laptop, wirelessly than it does to send it over a cable. And yet, when it is viable and safe and available at a competitive cost, it will be adopted broadly.


Because convenience trumps efficiency every time.

No matter how much we individually may want to reduce our energy costs, we will pick convenience over efficiency every single time. This is a big reason why electric cars have not been broadly adopted (in addition to concerns over cost and long-term value): a gas station is just that much more convenient, as I wrote two months ago.

Here is a simple experiment. Go ask your neighbour, friend, or spouse, the following 2 questions:

  1. How excited are you to cut your home energy bill by 5%?
  2. How excited are you to get rid of all of the laptop, tablet and phone plugs in your home?

Everyone wants both of those... but which one really got them excited?