The digital consumer lifestyle is one of the thorniest problems for the environment.
If you were to take a look around your home, which bits of electrical equipment do you think would be responsible for keeping the meter under the stairs spinning around like a fruit machine, but never paying out? The kettle. The cooker. The fridge and the freezer. And don't forget the washing machine. Thanks to their heating elements and motors, these are all machines that can chew through the Watts. But are they really using up all your energy at home?
"White goods used to be the main consumers of electricity in the home. Now it's computers," claimed Alain Anglade of the French environmental agency Ademe at the SAME electronics-design conference in Sophia Antipolis last month.
But, in the last 20 years, consumer gadgets from TVs to hairdryers have gradually overtaken the obvious candidates for energy usage. Heating and air-conditioning, particularly if you live in the US, remain the largest consumers of energy in the home. But the category that energy analyst firm Tiax refers to as "miscellaneous electronics devices" (MELs) has seen its share of electricity consumption climb to 24 per cent of domestic demand - a total of 298TWh - or 16 per cent of primary energy, which takes into account heating, among other things.
Tiax investigators Kurt Roth and Kurtis McKenney concluded in a June 2008 paper in the journal of US air-conditioning organisation ASHRAE: MELs account for a larger portion of residential electricity consumption than any other end use and the second largest portion of residential primary energy consumption (about half of space heating)".
Part of the reason for the rise in US electricity from the MEL category is down to sheer volume. Roth and McKenney explained: "Altogether, approximately five billion MELs are in the 115 million US households - more than 40 in an average household. Relative to prior estimates, the most recent estimate for the installed base of MELs is about 150 per cent greater than in 1976 and 45 per cent greater than in 1995."
Ted Vucurevich, CTO of Cadence Design Systems, says: "Much of our economic growth is about energy use. Part of the reason for our robust growth has been because we don't use energy well."
As the MEL category includes devices such as toasters, microwave ovens and hair dryers, you might expect a lot of the electricity consumption to be down to their different types of heating elements and motors. But their consumption is easily matched by devices you might not consider to be big drains on electricity.
In a report prepared for the Consumer Electronics Association, Roth and McKenney claimed the biggest single electricity consumers in the US were TVs and desktop PCs, with cable and satellite set-top boxes not far behind. Living-room gadgets, from audio players to TVs, accounted for 147TWh of electricity demand in 2006 in the US.
Flat-screen TV energy consumption
The Energy Saving Trust pointed out that one of the biggest contributors to the projected rise in energy consumption came from people buying flat-screen TVs. If you compare consumption on an area basis, LCD TVs should be more energy efficient than those based on cathode ray tubes. The problem, from an energy-demand standpoint, is that the flat screens make it easier to fit a TV with a larger screen area into the same space. Consumers have been busy trading up from 20in units to screens that measure 30in or more across the front.
Jacques le Berre, director of marketing and business development for power and lighting at NXP Semiconductors, says: "It's great when you can show your neighbour a flat TV. But the LCD is a big consumer of power because of the backlight."
Le Berre claims a change in backlight technology can make a major difference. Several manufacturers have looked at how moving away from today's cold-cathode fluorescent (CCFL) tubes to LED lighting can open up efficiencies. Today's LEDs are no more efficient than CCFL tubes at large area illumination but they are more controllable. You need to use tens or even hundreds of them to backlight a large LCD display. In many cases, with a dark scene, for example, it is possible to turn down many of the LEDs, leaving only those illuminating highlights on maximum output. If you have a processor controlling not just the LEDs but the LCD contrast, you can trade off backlighting against the display pixel settings to provide an image with equivalent or better contrast than a TV fitted with CCFL tubes for less energy.
"By using the LED power only when it is needed, we can achieve 40 to 60 per cent power savings. When you consider that the backlight power supply needs 200W to 300W, that is a huge power saving. Today, it is a bit expensive but there is great potential for this," explains le Berre.
Greater savings may ultimately come from a switch in display technologies to be purely emissive rather than interposing a switchable filter between you and a powerful light source. Today's emissive display technology of choice - plasma - is a power hog, although manufacturers such as Panasonic claim to have cut consumption by up to a quarter since the sets were first introduced, bringing them more in line with LCD TVs. A shift to notionally more efficient organic LEDs should provide further improvements but even that technology will run into limits in its efficiency.
Although manufacturers such as LG Electronics and Sony talk grandly of wall-hanging displays that could dwarf even today's 72in flat-screen TVs, size may be limited by how much energy they need rather than issues such as yield and production cost. Research performed at the University of Utah has suggested that the maximum quantum efficiency of organic LEDs may be just 25 per cent. Earlier estimates had optimistically pointed to a peak efficiency of more than 60 per cent.
Once you get past the power needs of big displays and power-hog PC processors, the focus shifts to what happens when you think the electronics inside are not doing anything useful. Ted Vucurevich, CTO of Cadence Design Systems, says of the 147TWh total calculated by Tiax, "30 per cent of that went into idle or 'power off' modes. You may have thought the TV was off but it's not. A lot of electricity powers black box [power supplies] when no device is actually connected to it."
In its report, the Energy Saving Trust pointed at set-top boxes and digital radios as major culprits for hidden consumption. Satellite receivers tend to be particularly power hungry, especially on standby, often consuming a significant fraction of their active power even while they appear to be off.
The problem with satellite decoders in particular is that they have to be able to receive even when not displaying a picture because they need to be able to download software updates and schedule information, and those transmissions can be delivered at any time. Manufacturers such as Pace Micro Technology have worked on techniques to try to reduce the amount of power its receivers use by trying to synchronise operation with network operators' update cycles.
The situation is more difficult for Digital Audio Broadcasting (DAB) radios. The problem for DAB radios in standby is similar to the situation with satellite-TV receivers. To stay updated with the Intellitext system, the radio needs to decode the signal even when it is off. There is no easy way to power down the radio and have it decode Intellitext messages. The solution used by companies such as Pure is to let the user disable Intellitext reception when the radio is on standby.
Mobile phone lifecycle
In many cases, the apparent solution is to buy newer hardware as it is more energy efficient. Some in the electronics industry want governments to go further than they have in telling consumers to save electricity.
"Prescribing mandatory limits per device is something that the European Union could do. It could drive innovation a lot faster," says Frans van Houten, CEO of NXP. "There is no reason why we should not show the world an ambitious agenda."
But simply replacing a house's worth of consumer electronics is not going to improve the situation if you take the lifecycle costs into account. There is a delicate balance between the environmental cost of producing and disposing of a mobile phone or a PC versus the amount of energy it produces during its working lifetime. The problem is that the useful life of some of these devices is very short.
However, even if you leave your mobile phone on the charger all night every night, you will probably have little impact on its overall environmental impact, especially as the latest models have chargers that are much better at switching into a low-current mode when the battery has been recharged.
A study by ESU-Services, Deutsche Telekom, Motorola and Swisscom found that the bulk of the environmental cost associated with a mobile was from its production.
"This is mostly due to its short service life," Mireille Faist Emmenegger and colleagues wrote in the International Journal of Life-Cycle Analysis. "The use of the phone is responsible only for approximately 5 per cent (UMTS) to 15 per cent (GSM) of the impacts. The impact of the UMTS mobile phone is about 35 per cent higher as compared to a GSM mobile phone."
Producing the electronic components for the phone accounts for the lion's share of environmental impact. "The production of printed wiring boards and integrated circuits make up about 40 to 50 per cent of the environmental impacts. The transport of the electronic components contribute with 18 to 25 per cent surprisingly much: this is caused by the air transport of the components."
In the case of large-screen TVs, the balance tends to lie in favour of updating technology to something more efficient - assuming you have not traded up to a larger screen. However, the balance is not weighted as much in favour of the newer technology as you might expect.
Even with a ten-year life-cycle, which is perhaps at the upper end of the scale now, a study by Chao Feng and colleagues at the South China University of Technology published in the Journal of Cleaner Production found that the greenhouse-gas emissions of the TV in use accounted for 68 per cent of the total. The remainder - a little under a third - came from manufacture and disposal. If you assume a five-year lifetime for that TV, the split between emissions from manufacturing and usage would be more or less 50/50.
The desktop PC perhaps represents the biggest contributor overall to greenhouse-gas emissions once you take the life-cycle costs into account. Anglade says: "Moore's Law is a big driver in terms of energy consumption. I have a personal translation of Moore's Law. In terms of the environment, the smaller circuits become the more they need in energy and raw materials."
Roth and McKenney saw desktop PCs as being the second largest user of electricity in homes among consumer electronics devices. However, the shorter life cycle of the typical PC means that its carbon footprint could be much greater. "We have some data from 2004," Anglade claims. "A computer made in 2004 needed for its manufacture the quantity of energy that it could use in three years of running 24/7. The situation is probably worse now."
Although attention is now focusing on the power demands of consumer gadgets, it could get worse before it gets better when you consider the impact from a market that convinces users to continually upgrade their hardware.