By Paul Rincon
Science reporter, BBC News
Governments should tax plasma screen televisions because of the large amount of energy they consume, according to a leading expert on climate change.
Plasma screens are getting bigger in size and energy consumption
Professor Paul Ekins, who studies the economics of climate change, said taxing plasma screens would reflect their "greater climate change burden".
This would encourage development and take-up of more energy-efficient diode screens, Professor Ekins said.
He said government should label energy-hungry appliances as a first step.
Plasma televisions, which are 50% bigger than their cathode-ray tube equivalents, consume about four times more energy, according to the government-funded Energy Saving Trust.
A cathode-ray tube TV costs about £25 per year to run and accounts for 100kg of carbon dioxide (CO2) emissions, whereas a plasma TV costs about £100 per year and accounts for 400kg of CO2.
But some researchers say exact comparisons are difficult because of the size difference between plasmas and other screen types: cathode-ray tube and Liquid Crystal Display (LCD).
"At the very least you might think that government would provide some differential incentives to accelerate the development of more energy-efficient diode screens and encourage their take-up," said Professor Ekins, co-director of the UK Energy Research Centre (UKERC).
"Once plasma screens are bought, they are likely to be there for five years at a minimum - perhaps 10 years, perhaps longer."
Organic Light-Emitting Diode (OLED) screens do not require a backlight and thus draw less power. But observers say the technology needs to overcome several technological hurdles, such as the limited lifetimes of some of the materials used in them.
Professor Ekins was speaking at a news conference in London held to discuss issues around the government's forthcoming Energy White Paper, including how to promote energy efficiency while reducing demand. The White Paper is expected to be released in the next few weeks.
He also singled out patio heaters as especially energy-intensive.
The economist, who is also professor of sustainable development at the University of Westminster, said he would personally like to see taxation on energy-intensive appliances such as these - and added: "The first thing for government to do is say these kinds of energy-intensive appliances are very climate-unfriendly.
"They ought to be labelled as such and then there needs to be a detailed policy analysis, which in my experience has not been done, to determine what is the best way to deter their take-up and to develop more climate-friendly substitutes."
He added: "Unless we have policy mechanisms of that kind we will not reduce energy demand sufficiently to achieve the kinds of reductions in carbon emissions that currently are the subject of the Climate Change Bill and are going to be signed into statute if that bill goes through."
But Robert Gross, head of technology and policy assessment at UKERC, said debates on energy efficiency could become too pre-occupied by prices and incentives.
"When you are looking at consumer appliances, buildings and vehicles and you are looking at people not responding very well to price-based incentives - for a variety of reasons - there's an absolutely fundamental role for straightforward legislation to improve the efficiency of these devices," he told journalists.
A survey of the five most populous European nations, carried out by the Energy Saving Trust, found that Britons were the worst energy wasters in Europe, with bad habits which could cost £11bn by 2010.