Most efficient method of tethering? I'm aware of this other quesion, but it doesn't answer with regards to usb-tethering:

Which method of wireless tether uses the least amount of power? Bluetooth or Wifi?

I'm going to use my android phone for tethering, so I can use the connection in my laptop. All following options are available on my phone:


usb tethering
bluetooth tethering
wifi-tethering


However, I would like to know the most efficient method in terms of power consumption. This article tells me that usb is the least expensive and wifi the most in terms of power consumption. Is that true?
Your question has some ambiguity. Bluetooth is a more energy efficient protocol than wifi. USB hardly uses any energy for the data protocol.

However, with USB the laptop can charge the phone, as is mentioned here before. From the point of view of the phone, compared to bluetooth and wifi, the phone's power consumption with usb can be negative.

From the point of view of the laptop, the USB method can consume MOST power, if you include the charging current. This can be an issue if you run the laptop on battery power.

The total power consumption of laptop and phone is another issue, that you probably are not interested in.