A February 2011 study commissioned by the Consumer Electronics Association (CEA) found:

Power use trends from 2003 to 2010 show a marked reduction, primarily in Active mode but in Standby mode as well. For LCD TVs, the Active mode power density dropped from 0.35 W/in2 in 2003 to 0.13 W/in2 in 2010, representing a 63 percent decrease; for Standby mode it dropped from a high of 6.1 mW/in2 in 2004 to 0.77 mW/in2 in 2010, representing an 87 percent decrease. In plasma TVs, for Active mode it dropped from 0.22 W/in2 in 2008 to 0.13 W/in2 in 2010, representing a 41 percent decrease; for Standby mode it dropped from 0.46 mW/in2 in 2008 to 0.07 mW/in2 in 2010, representing an 85 percent decrease.

Note this improvement is per square inch of display. Some of these gains are being offset by trend toward larger displays. The bottom line: weigh the energy impact of screen size, resolution, and technology when specifying displays for home or business purchase.

CNET reported in October 2010 that televisions displaying 3D images can consume up to 132% more energy than when they display 2D images. CNET also found models that consume no more energy in 3D mode, so pay attention to this spec when shopping for a 3DTV display.

Consumer Reports (10/08, p 26) compares a 14" 1938 B&W TV with a 50" 2008 plasma unit. Both consume 250 watts of power, which suggests that super-sizing television monitors is offsetting improvements in circuitry. The good news (p23) is that a similar size LCD unit consumes less than 60% of that power.

According to a March 2008 Consumer Reports article, a 50" 1080p plasma display can consume 40% more energy than a comparable 720p unit and twice the energy of a 40" LCD. These differences are significant in the home; they can really add up in a large media facility.