Power Electronics

Saving the World, 50 Million Adapters at a Time

My home has power supplies for a computer, monitor, printer, TV, amplifier, DVD, set-top box and multiple chargers. Larger families have additional computers, printers, TVs, game boxes and more chargers. Each household can choose between 250-W computers or 600-W gaming specials, and will actively use their PC for varying amounts of time. Which profile is typical?

With all these power supplies in use, the benefit of replacing a single power supply with a more efficient one is relatively small. The 90-W adapter supplied with a new notebook computer may operate at 90% efficiency and consume 0.36 W in standby. In contrast, an older adapter might be 82% efficient and consume 0.83 W in standby.

With the adapter plugged in continuously (which is typical), active use of three hours per day and $0.10/kWh, the consumer saves $1.18 per year and reduces CO2 emissions by 16 lbs using the newer adapter. Different calculations or assumptions will generate different results, reinforcing two points: one, these calculations are filled with assumptions, and two, currently a single more-efficient electronic device produces small savings. Most consumers would never notice the improvement on their electric utility bill.

However, government and industry can aggregate efficiency benefits across millions of households to highlight savings in energy costs and CO2 emissions. Improved product comparisons and household energy-consumption profiles will lead to compelling monetary and CO2 savings, even for a single device type. Aggregating the savings in the previous adapter example across 50 million households saves 589 GWh, $59 million and 800 million lbs of CO2. (Again, the exact numbers are subject to variance, but the magnitude remains the focal point.) Imagine the aggregate savings achievable from more-efficient TVs, computers, monitors and all the chargers used today, and it is clear how to get the attention of legislators, regulators, industry organizations and, yes, consumers.

To aggregate in this way, interested parties will need to make simplifying assumptions. Semiconductor suppliers, power-supply vendors and consumer electronics OEMs may all promote particular solutions that save energy in particular products. Theoretical calculations and laboratory measurements will be available to compare the energy savings as these products are deployed to the market.

But the range of products, power requirements and usage patterns means the total possible energy and CO2 savings from power-supply efficiency improvements cannot be accurately calculated or demonstrated without using averages, assumptions and extrapolations. Again, the important thing for the industry, government agencies and environmental groups to focus on is the magnitude of the possibilities, not on whether we can reduce CO2 emissions by 3 billion lbsor 3.05 billion lbs.

Individual consumers have little economic incentive to replace low-efficiency power supplies or to make energy efficiency a major criterion in electronics purchasing decisions. Similarly, the electronics industry has little economic incentive to provide a benefit, high energy efficiency, that consumers currently do not value highly and therefore will not pay for.

But by aggregating energy-efficiency benefits across vast numbers of consumers and types of electronics, the industry, government agencies and environmental groups can raise awareness of the societal benefits that arise from reduced use of energy. What is likely to emerge from higher awareness is more proactive environmental policy from government agencies with public support. While equipment providers may not enjoy responding to regulations, no supplier will be at a competitive disadvantage by deploying higher-efficiency power supplies in response to standards.

ENERGY STAR provides a viable alternative to regulations by raising public awareness of the aggregate benefits of energy efficiency, thereby increasing consumer demand for energy-efficient products. Some consumers will seek out these efficient, branded products and will pay more for them. This consumer pull provides an economic incentive to manufacturers to deliver products demanded by a growing segment of educated consumers. Companies can determine their own level of participation in this market, guided by practical market signals.

Eric Glatfelter holds a BSEE from Virginia Tech and an MBA from Loyola College. After six years of design engineering, Eric moved into marketing. He has been with ON Semiconductor since 1999, and has played a key role in positioning and promoting the company's GreenPoint reference designs for high-efficiency power supplies and adapters.

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