Environmental Screening and Evaluation of Energy-using Products (EuP) Final Report
9 Battery chargers and external power supplies (Lot 7)
- 9.1 Background
- 9.2 Environmental screening based on the Ecoinvent database
- 9.3 Ecolabel requirements
- 9.4 Technology and market trends
- 9.5 Conclusion
9.1 Background
External power supplies (EPS) and battery chargers (BC) are important to the operation of many electrical and electronics products. They especially accompany portable appliances which are found in increasing numbers in household and office environments.
A single voltage external ac-dc / ac-ac power supply (EPS) is designed to convert line voltage ac input into lower voltage dc output / into lower voltage ac output. A battery charger is a device intended to replenish the charge in a rechargeable battery.
These products are estimated to consume an important portion of daily electricity consumption. Apart from battery chargers sold individually for charging rechargeable batteries, EPS and BC are often delivered as a part of an end-appliance, e.g. mobile phone, laptop computer, inkjet printer, flat screen display.
The study on External Power supplies in the frame of the EcoDesign Directive [ECH2006] assumed sales in the EU for external power supplies and battery chargers of about 500 millions with mobile telephone representing about 50% of these sales.
The study estimated the current stock of external power supplies to be in the order of 2 billions, which correspond to an average of about 12 external power supplies per household, however the stock includes the external power supplies in the non residential sector. A better estimate would be to have 5 to 8 external power supplies per household.
9.2 Environmental screening based on the Ecoinvent database
The screening for battery charges and external power supplies is based on the Ecoinvent process: “Power supply unit, at plant”.
The screening is shown it Figure 9.1. From this it can be seen that the main contribution to the environmental impacts comes from the printed wiring board. However, the electricity consumption during use is not included, and this is presumably very significant for the overall environmental impacts.
An analysis of the printed wiring board for power supplies is shown in Figure 9.2. It shows that various electronic components contribute to the environmental impacts, especially the capacitor, the inductor, the integrated circuit, the printed wiring board and the transistor.
Figure 9.1 Environmental impacts from the assembly of a power supply unit.
Figure 9.2 Environmental impacts from the assembly of the Printed wiring board, power supply unit desktop PC, Pb containing, at plant.
9.3 Ecolabel requirements
It has not been possible to identify relevant Ecolabel criteria for this product group.
The only energy efficiency policy in place at the moment is the European Code of Conduct[³], which was introduced in year 2000 to reduce the no-load losses, and recently also to improve the on-mode efficiency.
9.4 Technology and market trends
External power supplies are contributing massively to the increase of the electricity consumption. External power supplies are used for many different types of electric and electronic devices, but most frequently as charges for mobile telephones, digital cameras, cordless phones, and notebook PCs. However, large quantities of external power supplies and chargers are now also being found for kitchen tools, power tools, games, etc.
The number of mobile phone subscribers in the world has now surpassed 3 billion units. Although not all of these units are in use (many are older types that users save for later), serious estimates indicate that more than 2.2 billion phones are in active use. In many of the lately developed countries (eastern and central Europe, China, Southeast Asia and Africa), have prioritized the roll out of wireless communication networks rather than building fixed networks. The table below show the large increase in mobile phone users.
Other devices are believed to have the potential to show an even higher growth, as the concept of the Networked Home (or Internet of Things) gains momentum. While the development of intelligent devices ushered in the information age, the connection of those devices to one another increased their power and utility by an order of magnitude. Thus, while the home PC saw increasing popularity as functionality increased and prices decreased, only with the introduction of the Internet and the resulting connectivity have PCs become a fixture in the mass market [Bea2001].
Home networking, defined as the connection of intelligent devices to each other and the Internet within the home, is very useful but not yet as compelling to consumers as the Internet-enabled PC, once the standardisation and interoperability issues have been solved.
The emergence of a standard interconnection as well as interoperability platform will drive both home networking and the digital home and thus require a great deal of home networking components for automation, monitoring and security. All the devices will be supplied with power either from batteries (hence with a significant environmental impact), by individual external power supplies (thus adding massively to the energy consumption of private dwellings) or from new and ingenious sustainable energy picking micro sources, using sun, wind, pressure or other natural energy sources.
The European Code of Conduct (CoC) for external power supplies, was introduced in year 2000 to reduce the no-load losses, and recently also to improve the on-mode efficiency.
In Figure 9.3 and Figure 9.4 below are shown the results achieved by the participating manufacturers in the CoC. Before the introduction of the Code of Conducts many external power supplies had no-load power consumption above 1 W, and low efficiency in operational modes.
By 2005 many of the external power supplies in the European market have no-load losses below 1 W.
![Figure 9.4 New efficiency criteria for external power supplies and results achieved by participating companies (Source: [Har2006])](images/s79b.gif)
Figure 9.4 New efficiency criteria for external power supplies and results achieved by participating companies (Source: [Har2006])
The so-called switch mode design has been used for ages in high-performance power supplies but is gaining increased interest also in the low end (below 25W) typical for external power supplies. Switch mode power supplies have the advantage of
- Very high efficiency both at low and high load
- Very low no-load power consumption
- Wide input voltage range (Full AC-range possible)
- An overall simple control circuit
However, there are also drawbacks from this design:
- More complex when compared to conventional design
- Switch mode generally requires EMC (Electromagnetic disturbance) considerations
- Can make audible noise at low load
- More expensive compared to conventional design
A relatively promising design technology for switched mode external power supplies is the TinySwitch® family from Power Integrations, Inc., USA, which claims to overcome almost all of the negative drawbacks above [PCI2003].
The TinySwitch uses a switch mode design to provide low cost, high efficiency, off-line switcher solution in the 0 to 10 W range, which is more than sufficient for mobile phones and standby operations of most consumer electronic devices including televisions.
The chargers run on power derived from the internal semiconductor circuits, thus eliminating the need for power consuming transformers. It continuously measures the load applied to it and switches the power cycles to a minimum, when no load (less then 40 µA) is present. This design allows for a no-load power consumption of only 80 mW placing it in the lower left square in the Figure 9.3 above. Moreover, the design also provides very short power up/down times (time to come alive and turn off), typically within 0.3 msec, thus making it very useful for standby operation of critical equipment like network and communication components.
9.5 Conclusion
In the view of the authors, the environmental aspects important for battery chargers and external power supplies are much the same as the environmental aspects that are important for personal computers (same issues, same problems, just in a smaller scale). Please refer to the section about computers.
9.5.1 Environmental perspective from new technologies
Ongoing development efforts have tried, but failed, in standardising certain types of external chargers, such as those used for mobile phones. However, this has, for various reasons, been resisted by the manufacturers. One technical reason is that the charger must closely match, in terms of charging current, the battery used in the phone, in order not to cause serious damage. From a product liability point of view, manufacturers wants to have control over which charger is used. This can be done by making the connector plug brand/model unique. Another point is the lifetime of the battery and the derived product image. Incorrect charging of some types of batteries may reduce the lifetime and adversely affect the brand image.
The trend towards mobile and handheld computers will lead to increased use of batteries and increased need for external chargers. The authors think that it is important to take future needs for mobility and ease of use in networked civic applications (such as mobile healthcare, work-force mobility, etc) into consideration when implementing EuP requirements.
[3] all the information can be found at: http://energyefficiency.jrc.cec.eu.int/html/standby_initiative_External%20Power%20Supplies.htm
Version 1.0 December 2009, © Danish Environmental Protection Agency