It IS possible that wireless chargers are greener than badly designed and badly deployed wired chargers that are left plugged in drawing a little power 24/7.
I agree there is the issue of a single piece of equipment made, packaged and shipped versus multiple chargers.
If wireless chargers, through their convenience, catch on and become ubiquitous; and they are standardized to charge a multitude of devices; and if by eliminating the mechanical plug and socket, the wireless chargers have much longer lifetimes than the wall-warts and USB cables they replace: Then might not wireless charges reduce resource waste, and the energy wasted in the manufacture and distribution of countless charging devices that currently come included with almost every commercial electronic device? Perhaps wireless chargers though less efficient at their task, are potentially greener over their lifetimes when all factors are considered.
The efficiency question will never go away, but it will become less and less or a factor. Consider the required battery capacity of a phone. Years ago, very large batteries were required. The battery size dropped over time as the electronics became more efficient and the transmit power dropped.
Battery capacity took a big saw tooth back up with Smart phones, but it will eventually work its way back down again. My pre-smart phones typically could go about a week without being plugged into a charger. My smartphone needs to be charged every day.
Once we work back to that level, then charging energy will be a much smaller factor. There are ways to deal with phantom power too. Consider a system where the wireless charging plate would draw a few micro amps when not charging anything. It may even be possible to completely disconnect it from the wall. I would venture a guess that most corded chargers are just left plugged into the wall.
The universal charger already exist: through USB port. I got a smartphone, a tablet and a normal old mobile phone. All got the USB-charger port. I got an USB adaptor for the wall/car... since then I charge only through USB port.
Yes, we are lazy. Having a pad to throw my phone on at the end of the day is much easier than getting that little micro USB connected. On the other hand, I am very stingy with my money, so I will plug the little connector into the phone rather than pay extra in energy costs.
Frank, an efficiently designed car, running at 50 mph, requires about 12 to 14 HP to maintain a steady speed. So if the alternator needs 1.5 HP to turn (thanks for the number, I didn't have it at hand), that's a substantial 10-12 percent of the total output of the engine.
Car and Driver used to post two figures with their road tests, some time ago. The HP required at 50 and at 70. Obviously, the number is higher at 70.
A quick search on the subject of mpg cost of running an alternator reveals calculations varying from 1 to 1.5 HP when the alternator is putting out 50 amps -- a substantial load for a passenger car (excluding EVs of course). Let's assume this means a properly working alternator, no belt slipping, etc.
On a modest 4-cylinder with 100 HP, we're talking 1-1.5% HP loss to run the alternator at a 50A load. A 5 watt cell phone charger will pull less than 0.5A from that 12V regulator. Let's be generous and call it an amp -- it's still only 2% of the alternator output, which translates to 0.03% of the HP loss due to running the alternator.
In the usual manner of engineering approximations, I'll go out on a limb and say that a 0.03% loss of HP translates to a 0.03% loss of mpg and that you will never notice that.
So when it comes to charging your phone or even your big tablet in the car, charge away! The cost in extra gasoline is almost immeasurable.
A one size fits all wired charger would be a good thing, although it goes contrary to the best interests of individual gadget-producing companies. Who would much prefer to add the revenues generated by a proprietary charger, and possible future replacements, to their bottom line.
I was astounded, for example, to discover that I couldn't find a replacement charger cord tip to fit an old appliance we had. Radio Shack sells a bunch of these in assorted sizes, and yet not a single one worked. I wonder why.
Anyway, that aside, I'd say wireless charging is bound to waste energy compared to wired. Not just to radiation, but also to the extra circuits needed for transmission and reception.
You'd think that a load sensing shutoff on a wired charger would be a doable do. Wouldn't be free, but in huge numbers, should amount to much of a price hike.
Peter does make a good point, though. Negligible is true enough, perhaps, but alternators do place a load on the engine.
Many years ago now, one of our neighbors had a brand new car, and complained that the battery was running down. The charging light was coming on when the car was running.
Since the car was brand new, my first reaction was to tug a little on the fan belt. Yup. It wasn't very tight.
A simple adjustment solved the problem. Point being, that alternator wasn't turning, just because the belt wasn't tight. It was in place okay, but it was slipping. That's engine load.
I agree also with iniewski. Are we really that lazy?