Wireless Power

There are signs of maturing technologies for wireless power delivery. And I don't mean proximity power delivery like Qi, which is present in many Android phones and the latest iPhones. We're talking of wireless power delivery at a distance. 2018 should bring the first products to the market, and I'd expect some announcements as early as at the 2018 CES.
What has so far come to my attention:

• Pi says it has already delivered. It uses resonant receivers.
• Energous has just received an FCC certification for their power-at-a distance wireless charging systems
• Power by Proxi (I saw their working demo in 2016) was acquired by Apple. Again, this is based on resonance.

One thing that keeps me still a bit skeptical is influence of these power transfer technologies on human health. And here I'm speaking from my own experience. About 30 years ago (mid 1980's) I built my first stereo wireless headset (yes this had been 15 years earlier than the first version of Bluetooth was created). The device worked on a simple principle: inductive coils. I guided 6 loops of wire around my room (at a floor level) and another 6 loops around one of the walls, effectively created two giant coils perpendicular to each other. Then in my headset I had two small perpendicular coils, one connected to the left magnetic membrane, the other to the right. The perpendicular orientation was to minimize cross-talk between left and right channel. The big coils were then connected to speaker outputs of an audio amplifier. The system worked surprisingly well.

Except.

Except I could not listen to it for more than a couple of minutes, as an immense head-ache was building up immediately when I fed music to the coils. Clearly the head-ache was related to the presence of a strong magnetic field. I was inside two coils, after all...

Several years later I was having the same painful experience when using one of the first analog cellular phones. I could really feel the antenna close to my head radiating a couple of watts of radio waves. Not sure if I am overly sensitive to strong magnetic fields, but even if, I'm probably not the only one.

I think the wireless power transfer systems will be facing an uphill battle because of health concerns. This is definitely an interesting area to watch but this time I will probably not be the early adopter of any of these technologies...