The Energy Review has brought concerns about the growth in the amount of standby power in domestic electronic equipment to the forefront of the industry. But just what is being done to hit the maximum 1W levels? George Warren from the environmental engineering department at Nottingham University investigates.
The Government’s Energy Review draws particular attention to increasing concerns about the growth in the amount of standby power in domestic electronic equipment. It commits us to working towards all electronic devices using a maximum of 1W for standby purposes.
Standby power consumption accounts for 1% of the worlds CO2 emissions. If all appliances used only 1W or less in standby, it would result in an 80% reduction of the current CO2 emissions related to standby, a reduction of at least 54 million tonnes of CO2 each year.
The average electricity use for standby power in the European Union is 400 to 500kWh per household, at least 60TWh a year for the EU as a whole. Happily that can be reduced significantly with minimal effort – but with maximum policy co-ordination.
Standby power, formerly known as ‘leaking electricity’, traditionally referred to the electricity consumed by electrical equipment when supposedly switched off or not performing its main function. But definitions seem to vary. Many now see it as power consumed by an appliance during the lowest possible electricity-consuming mode. Unfortunately people have used one or another of these definitions in the past, meaning measurements are not always comparable. While in 1999, the International Energy Agency (IEA) officially defined standby power as referring to the appliance’s “lowest possible consuming mode”, nonetheless several commentators still use the first definition – causing continuing confusion.
The relevant appliances range from televisions to set-top boxes and microwave ovens to cordless telephones. Each product uses varying amounts of electricity whilst in standby. This could be to maintain a digital display, or to be alert for remote control demands or even just wasting the electricity due to poor efficiency.
The actual power draw in standby mode is relatively small, typically 0.5-3.0W. Although at first glance such losses may seem trivial, the problem assumes significance because these products are consuming 24 hours a day: the cumulative total soon adds up. For example, a New Zealand study into the power consumption of microwave ovens found that 40% of them consumed more electricity over the course of a year in standby mode, merely powering the clock and keypad, than in cooking food.
As new electronic equipment continues to proliferate at increasing rates, so too will the energy used attributable to standby power, with more and more goods utilising a standby function.
The standby function can aid the efficiency of a device, as it will undoubtedly use less power than if it were in its normal function. But the degree to which it continues using energy is of concern, as technology is available to reduce the standby power consumption of their products.
Nevertheless, the problems will remain while people still use their older models never designed with energy efficiency in mind. What is really needed, is an incentive for the public to change wither their habits, by turning the equipment off at the mains, or swapping their existing devices for new more efficient ones.
Scale of the problem
Standby power can be measured directly using a high-resolution watt meter. Unfortunately these can be very expensive and difficult to find, so it is unlikely to be a realistic option for customers to test all appliances themselves. Instead there are three ways in which standby power can be quantified.
• The whole-house measurements – Measuring the standby power consumption of every single electrical appliance that consumes standby power in the home.
• Bottom-up estimates – Estimates of either the average standby power consumption per home or the national standby power consumption. This data is normally based on measurements of individual appliances and then multiplied by the amount of devices in the specific area. These estimates utilise a combination of field measurements and known appliance saturation. Although usually accurate for larger appliances, it is not the case for minor ones, as little information is known about their saturation. Therefore bottom-up estimates probably underestimate standby power usage.
• New Product measurements – Measurements are made within the stores of factories, so all new products’ standby power can be measured at one time. Quick and accurate but unfortunately these results omit the performance of older products.
There are three principle research strategies to reducing standby energy consumption:
• Improve (or modify) technologies outside the device and change user behaviour
• Improve the efficiency of the components
• Improve software to help equipment operation better match functional needs
An example of this is the simple power switch design. Pictured are three different power supply set ups:
Fig. 1: Design A is accomplished by placing the switch between the power source and the power supply. This is the perfect solution for eliminating power consumption,as the current does not reach any energy-consuming components.
Fig. 2: Design B has a switch placed in between the power supply and the appliance, which is the case in a significant amount of conventional electrical equipment. Even when the switch is turned off or no appliance is connected to it, the power supply will continue to receive a flow of current and the energy is then usually dissipated as heat. This is a prime example of the manufacturers not adapting their designs to prevent loss of energy.
Fig. 3: Design C shows a secondary load, for example a clock, which requires energy even when the main load is switched off. This can be achieved by:
• Adding an extra power supply for use at low-power levels.
• Using a power supply with two operating ranges (‘on’ and ‘standby’).
• Incorporating a separate source such as a small battery or a photovoltaic cell to power the secondary load.
The other alternative is of course to teach the public to switch their appliances off at the mains when they are not using them. A classic example of this is the phone charger. Many people wrongly assume that when a phone is finished charging, it will cease to draw electricity from the supply. In fact, even when the phone has been unplugged from the charger, if the charger is still connected to the power source there will be energy consumed in the form of heat.
Educating the public into switching any accessible electrical equipment off at the mains would solve the standby power consumption problems. Of course, turning each appliance off at the mains is not always practical. In these instances, the manufacturers need to improve their components efficient.
Two approaches to this are to either improve existing standby mode components efficiencies, or to use new of different components that require less power.
• Power supplies - There are two main types of power supplies, linear and switch-mode. Switch-mode is the more efficient of the two, and could have a major impact on reducing standby power consumption if chosen instead of linear power supplies. Standby power can also be reduced by the addition of a separate/secondary power supply that consumes less energy than the supply used when the appliance is in active mode. An alternative may also be to incorporate a small battery or photovoltaic cell.
• Voltage Regulators - Voltage regulators tend to dissipate a large percentage of the power supplied to them as heat. This increase in heat also shortens the life of the appliances. It is possible to reduce overall standby power by using a more efficient voltage regulator. Another option is to reduce voltage levels, so that fewer voltage regulators are needed.
• Visual Displays - Changing the type or size of visual displays can save power. An LCD screen is the most efficient, although new lower power LEDs are becoming available and are often more practical.
Improvements enable the device to change operating time from active to sleep and then from sleep to off. Although this results in large power consumption when in low power modes, it does improve overall lower energy use.
There are technical solutions that currently exist, which have the ability to reduce the standby power consumed by up to 90% - but are seldom exploited. Additional capital costs to reduce standby power consumption of most appliances are surprisingly modest and will almost always result in lower costs or new benefits elsewhere. The simple fact is that although the new products may cost a small amount more they will easily save the amount on the electricity they do not use, compared to older, less efficient models. As on of the world experts, Alan Meier of the US Lawrence Berkeley Laboratories says: “Most technical solutions are cost-effective given the current price of electricity.”
Nine years ago, the European Commission negotiated agreement with the European Association of Consumer Electronics and Manufacturers (EACEM) setting targets of less than 6W for standby consumption of TVs and VCRs. Ever since then, new targets have been negotiated on various appliances. This has been seen as an effective way of gaining suitable efficiency levels, preferred to setting mandatory efficiency requirements.
Standby levels are not as low as 1W yet, but in 2000 the average standby consumption for new products was 3.7W for TVs and 3.8W for VCRs. Negotiations continue with EACEM with regards to other appliances, and no doubt will do until all reach the 1W mark. Set-top boxes (STBs), the digital television boxes used to receive satellite television channels, seem to be the biggest problem in Europe, as they consume large amounts of power whilst in standby mode. The problem is that the service providers require such devices to remain constantly on, to permit remote access for downloading new software and updates.
In addition, STBs are produced to the specifications of the service provider and so there is no incentive for them to reduce the power consumed in its standby mode. In 2001, the European Commission issued the EU code of Conduct for Digital TV Service, which set the maximum standby power consumption at 9W. This is unfortunately not as low as the 1W at which everything is aimed, but it is a step in the right direction.
Power supplies have also been seen as a problem, often consuming power even when the appliance is switched off. In July 2000, the European Commission issued a Code of Conduct on Efficiency of External Power Supplies in order to reduce the power consumed in standby. The EC then promoted this within the IEA standby initiative for adoption worldwide, as many of these power supplies are traded globally and also many of the manufacturers are not based within the EU. This is still to be accepted internationally.
Elsewhere the Australian government is actively considering a Penalty Labelling Systems, publication of all standby statistics, and perhaps even a Mandatory Energy Performance Standard where the least efficient models on the market are removed. These are yet to be implemented but are being seriously considered in order to improve the situation.
In America, Executive Order 13221 requires every government agency “when it purchases commercially available, off-the-shelf products that used external standby power devices, or that contain an internal standby power function, shall purchase products that use no more than 1W in their standby power consuming mode.”
A Japanese study in 2000, found that standby represented 9.4% of the Japanese residential electricity use. This led to an announcement by several thousand household application associations at the Subcommittee for Energy Conservation of the Advisory Committee for Energy and Resources of the Japanese Ministry of Economy, Trade and Industry 2001, that they intended to reduce standby power consumption to less than 1W or eliminate it entirely by the end of 2003. Unfortunately, no information was found to confirm whether this target was ever reached.
Evidently many national and regional initiatives on regulating standby power use exist. However, it is imperative to coordinate efforts internationally to facilitate participation by industry. This is one of the aims of the IEA initiative. To date, it has failed to generate a joint solution for the most common standby power consuming devices or worldwide discussion of an agreement on requirements for digital TV equipment. But it has achieved the feat of gaining inclusion in energy test protocols and energy efficiency policies for all products that consume significant standby power.
Although success has been achieved in come cases, the standby power problem still presents uncertainties. As the UK government has identified, considerable potential energy savings can be associated with the reduction of standby power in new electronic equipment. It is therefore appropriate to make some recommendations to guide future policy:
• Increase public awareness
• Develop worldwide implementation of regulations
• Improve electrical equipment design
• Develop guidelines for lowering standby power use in appliances no currently covered by any programme
• Establish an international network of accreditation organisations
• Include standby power information on existing appliance energy labels
Internationally coordinated efforts would reduce the burden placed on manufacturers of globally marketed electrical goods. This is the most effective way to achieve an increase in global penetration of these technologies.
Certainly, the anticipated growth in standby power is decreasing, as multinational companies understand the need to reduce the standby power consumed by their products. This progress is encouraging, but there remains an urgent need for government intervention in order to stimulate and reinforce these achievements.
- Font Size
- Reading Mode