After sleep and work, TV viewing is what Swedes do most. A study funded by the Swedish Energy Agency shows that a majority of households have two or more TVs at home, while almost everyone has at least one. TVs use about five percent of the household electricity in Sweden. Another 14 percent is used to operate computers and their displays. Computers and monitors are also used extensively in various workplaces. Playing video games also play an important role in the overall energy consumption.

Early flat screens were energy guzzlers

Previously, there were thick TVs based on cathode ray tubes in almost every Swedish household – the same technology used for computer monitors. When flat screens came they quickly penetrated the market. The new plasma screens saved space but also had better picture quality. But they were criticized for using a lot more energy and were thus less environmentally friendly. In mid-2008, Miljöaktuellt warned that plasma TVs were large energy users.

Thick-TVs and early flat screens devoured a lot of energy

Higher performance and lower energy consumption

Each pixel in a plasma screen consists of a distinct light source. To obtain a high resolution many pixels were required, which created the need for the screen to light up many individual sources. Over time, LCD technology developed to use one common light source to illuminate the flat screen. Special properties of the liquid crystals were used to generate pixel colors in a more energy efficient manner. In recent years, LED technology has become increasingly popular. LED, or light-emitting diodes, are even more energy efficient. The transition to LED has pushed down prices and made TVs thinner. Interestingly, LED screens use less energy than plasma screens. According to The Guardian, LED screens use as little as one-fourth as much energy as the old thick TV screens. In the near future, new technologies could further reduce the energy our TVs use.

Next generation displays, even more energy efficient?

Researchers and companies are currently working on a new generation of flat screens that will be even thinner than today. The new displays are based on so-called quantum dot technology, which utilizes light-emitting crystals. The crystals, which can be so small that their diameter is only tens or hundreds of atoms wide, are expected to create high-resolution images. One advantage of the technique is that it can potentially be used to print screens on surfaces that are so flexible that they can be rolled up. Another advantage of the quantum dot technique is that relatively little energy is needed to produce a high quality image. Therefore, the new displays will be extremely energy efficient for TVs, computer monitors and on smart phones. The same can be said for another new screen technology, based on organic light-emitting diodes (OLEDs).

Many are investing in the new technology

The first generation of displays based on quantum dot technology has not yet been launched. The Nanoco company, created by scientists at Manchester University, has garnered attention for its work on quantum dot technology. Even electronics giants like Sony, Samsung, Sharp and LG are investing in the new technology, even if the companies are reluctant to go out with details. OLED technology is already being used in MP3 players and on mobile phones, but it must be cheaper before it can be used for TV screens. The potential however is clear that the new generation of screens will be more energy efficient. These developments illustrate the importance of existing technologies becoming more environmentally friendly. When new technologies are launched, it usually takes some time before they are optimized. Therefore, a new technology, which at the start is less energy efficient than its predecessor, with time evolves to become more so.

The article was published in September 2012