A recent article (12/8/06) on the BBC News web site questions if plasma HDTVs are hostile to the environment. The article quotes the UK-funded Energy Savings Trust (EST) as saying "… old-style TVs produce 100kg of climate-warming CO2 per year - while larger, plasma screens will pump out 400kg."

Further, the EST states, that "…on average, the power consumption of a cathode-ray screen is 3.4 watts per screen inch, while plasma uses 9.4 watts per screen inch - based on figures from 2005."

The story brought an immediate rebuttal from Philips, who sells both plasma and LCD HDTVs. A Philips spokesman argued that there is no standardized consensus for measuring power consumption in plasma TVs, and then confused matters by stating Philips’ 42-inch LCD HDTVs have been recognized for their low power consumption of only 210 watts. (The article also mixes discussions of LCD and plasma technology.)

Given the plummeting retail prices for plasma HDTVs, there will be a lot of them sold through the rest of the holiday season, not to mention during the weeks leading up to the 2007 Super Bowl. Are consumers really that concerned about the possibility of higher electric bills?

Some appear to be and others don’t, judging from the responses to the article, which ranged from "We are surely heading for an environmental crisis" to "Shut these people up, I want to enjoy the fruits of my labors." One respondent even stated (perhaps tongue-in-cheek) that the heat from the plasma HDTV would cut down on his central heating bills.

In side-by-side tests that I have conducted over the years, plasma displays consume, on average, about 20 - 25% more electricity than same-size LCDs equipped with CCFLs. (I haven’t tested any LCD HDTVs with LED backlights yet.) Some plasma HDTVs do better; some do much worse - I have measured 50-inch sets with over 500 watts of power consumption. Nevertheless, the source of the content is a big factor in power consumption in PDPs, so a simple answer is elusive.

Another culprit seems to be the standby mode built into many new HDTVs to keep some circuits idling and enable a quick start-up. Standby modes are also found in set-top boxes for cable, satellite, and terrestrial reception. (Got a TiVo receiver? They never shut down!)

The challenge for PDP manufacturers - aside from long-term profitability - will indeed be power consumption as LCD HDTVs grow in size, and if - IF - the SED ever makes it to market. In an impressive demo I saw at CES 2005, a 36-inch SED consumed all of 80 watts, compared to a 260-watt 40-inch LCD and 400-watt 42-inch plasma monitor.

If you want to see for yourself just how much juice your new plasma or LCD HDTV uses, pick up a WattsUp? power analyzer ($139.95). It’s available direct from Electronic Educational Devices (www.doubleed.com) and provides all sorts of data and graphs on peak and average power consumption for any appliance.