When considering the purchase of a plasma or LCD TV many people are concerned about how much power it uses and increasingly what the total environmental cost is.

There are three stages in the "life" of a TV that have a cost to the environment. These are:

• Manufacture
• Home use
  
• Disposal

This article considers the total environmental impact of TV's and how you can make a difference by making an informed decision about which TV to purchase.

1. Home Use

First a bit of background on the technology. 

There are four main types of technologies used in TV's to display an image. The type of technology used has a large influence on power consumption of the TV.

The old fashioned TV set or Cathode Ray Tube (CRT) blasts electrons onto chemical phosphors embedded on the inside of the tube, while Plasma sets ionize gas to create colours in a million or more tiny pixel cells. Both these technologies require more electricity to create a brighter image.

On the other hand, flat-panel Liquid Crystal Displays (LCD's) use a powerful fluorescent back light that shines through the three colour filters of an LCD panel.  Most LCD TV's consume the same power, regardless of the brightness of the image. That's because the back light is always on full. Nowadays clever LCD TVs actually have backlights that only turn bright in the areas of the screen where needed.

For example Sony's BRAVIA series of LCD televisions automatically adjust back light intensity in response to the brightness of the image and adjusts the screen brightness in response to ambient brightness. Thanks to such features, the KDL-40J3000 model has achieved 180% for the energy-conservation standard of the strict energy-saving laws in Japan. 

The emerging technology is Organic Light Emitting Diodes (OLED's) based screens that are basically a large array of small LED lights in an ultra thin screen. OLED technology promises to be about twice as efficient as current technologies. Sony has announced small screen OLED televisions will be available from December 2007 in Japan.

Household Power Consumption - Size matters

Televisions are consuming a greater share of household energy bills as Australians move to new display screen technology, select larger screen sizes and leave televisions and other equipment on ‘standby' which still uses energy.

Peak power consumption occurs while the TV is on with bright, moving images.  The greenhouse gas emissions or carbon footprint of your TV is related directly to total energy consumption of the device and that in turn is most related to how large your set is and how long it is on for. 

In other words size matters. Even within comparable sizes, energy use differs significantly between brands. 

Standby Power Usage

"Standby" refers to the fact that most modern TVs are not completely turned off when not functioning - they are in "standby" mode which can draw anything from less than a watt to 20 watts per device.  Many home theatre and HiFi devices have a standby mode and when totalled up, the power consumption can be as much as leaving a light on all the time.

The United States and Japanese governments have introduced energy star ratings for televisions and in response international manufacturers such as Sony, Panasonic, Sharp and Mitsubishi have dramatically improved the energy efficiency of their models.

Manufacturers have dropped standby power usage from over 20 watts/hour to less than 1 watt/hour to meet the energy star ratings.

Broadcast power

Large amounts of power are used by TV stations to transmit regular TV broadcasts to your home.  Much less power is used if you are connected to Foxtel or Austar or you download your programs over Broadband Internet. 

Because Australia is such a large country the government pays the broadcast power costs for ABC and SBS, which reaches many million dollars per year.

At the moment Australia uses about twice as much power than needed because signals are transmitted in both Analogue and Digital formats during the switch over to Digital period.  A speedier change over to a digital service would reduce these power costs.

2. Manufacturing

The manufacture of televisions and the composition of the materials used also have an impact on the environment.  Considerable energy is used in the manufacture of highly refined glass and semiconductor components to go into creating a new TV.  

Another aspect is the transport and packaging of these fragile goods. Larger retailers are moving to minimise packaging and use recyclable packaging materials.

International manufactures have recognised that the environmental footprint of their products is important.

Leading manufacturers of LCD and Plasma TVs like Sony, Phillips, Samsung, Panasonic and Hitachi have 'corporate social responsibility' programs. For example Sony has a policy of transporting its goods by Rail and Sea rather than Truck and Air thus substantially reducing their transport energy costs Sony's annual report has more information.

3. Disposal

Australians are becoming more concerned with the toxic substances used in electronic devices such as Mercury, Cadmium or hazardous Bromide flame retardants and plastics including PVC, which persist in the environment.   Strict European standards have caused international manufacturers to move to more recyclable materials and to take responsibility for the final disposal of out of date equipment.

Summary

Information is the key to minimising the environmental impact of a new television purchase. Using the available information from Comparison Net, manufacturers and retailer websites you can:

• select an energy efficient model with an appropriate screen size;
• choose an international manufacturer demonstrating corporate social responsibility; and
• find a local retailer who shares your environmental concerns.