In order to meet the increasingly stringent US and European energy consumption standards, ABL was implemented on plasma TVs a number of years ago. Plasma is a self-illuminating technology, unlike LCD which has a backlight that's always on. So the PDP is consuming the most energy when showing a white frame, when all subpixels are illumated at maximum brightness. OLED works the same way, but at a dramatically lower energy consumption and heat emitted. The OLED panel on your phone uses more energy while showing a white screen than a black one, in theory both PDPs and OLED displays use no power when showing a black screen beyond the supporting electronics.
The ABL limits the brightness of the picture based on the amount of energy being consumed, so you can easily see this by showing a 50% white/50% black frame split any way you like, and then a 100% white frame. The 50/50 frame will have a much brighter white side then the 100 white frame.
One reason plasma has been dying is the manufacturers have aggressively researched ways to increase panel efficiency but it has not been keeping up with the yearly changes to Energy Star (US) and TCO (EU) standards. This is why if you are to put up a 100% white frame on a plasma TV today, you will have only 40% of the panel's theoretical maximum brightness as limited by the ABL. That's right, 40%.
Note that a 100% white frame, limited to 40% of the panel's theoretical peak brightness, still sucks ~430W of power from the wall. The equivalent LED-sidelit LCD HDTV uses less than 100W of power to light it's efficient LED side-lights.
Remember that power consumption (and heat emitted) increases as a square of pixel density. Now imagine how much power a 4K plasma would consume, and how hot it would get. Yup, that's why there aren't going to be any 4K plasmas.