Energy savings assessment for digital-to-analog converter boxes
Research highlights
► We examined energy efficiency policies on digital-to-analog converter boxes in US. ► The government assistance program resulted in high participation. ► 35 million coupons were redeemed for the purchases of energy efficient DTAs. ► Between 2500 and 3700 GWh per year are saved as a result of the policies. ► Savings are equivalent to the annual electricity use of 280,000 average US homes.
Introduction
On June 12, 2009, the United States switched from analog to digital over-the-air television broadcasting for all full-power stations. The US has about 110 million households with TVs (Nielsen, 2009) and was the largest market to have made the transition. Many consumers had not yet purchased digital televisions that were able to receive the digital signals. In February 2008, at least 13 million households in the United States had analog televisions that could receive only analog broadcast signals (Nielsen, 2008). There was widespread concern that these households would not be prepared for the transition and would be unable to receive a television signal.
In order to facilitate the Digital Television (DTV) transition, the Digital Television Transition and Public Safety Act of 2005 authorized the National Telecommunications and Information Administration (NTIA) to establish a DTV Converter Box Coupon Program (Federal Register, 2007). Eligible households could receive up to two $40-coupons, between January 1, 2008 and July 31, 2009 (expiring 90 days after they were issued), toward Digital-to-Analog converter box (DTA) purchases. These $40-coupons covered most of the converter box cost, which was typically $50–60.1 Through December 2009, about 35 million coupons were redeemed from the NTIA coupon program (NTIA, 2009).
In 2004, there was concern regarding the potential energy impacts of DTAs (Meier, 2004). These boxes were expected to continuously draw as much as 20 W, or 180 kWh/yr. For example, ten million boxes, each drawing 15 W, would add 1300 GWh per year to national electricity consumption. Several studies described at the 2004 and 2007 International Energy Agency (IEA) workshops indicated that the boxes could be manufactured to consume much less energy at only a modest increase in cost (Dale, 2004). The California Energy Commission therefore initiated hearings to establish minimum efficiency standards for DTAs. Other states were poised to enact similar standards.
Negotiations among the major stakeholders resulted in an agreement that proposed mandatory regulations would be withdrawn but that coupon-eligible DTAs must also meet certain energy efficiency requirements. Separate from the NTIA coupon program, the Energy Star program established voluntary energy efficiency specifications that were more stringent. Energy Star compliant DTAs were also required to comply with all NTIA coupon program specifications.
Few, if any, energy-using products have entered widespread use as rapidly as the DTA. The increase in electricity consumption from a new product is also unprecedented. About 79% of countries around the world have not started the DTV transition, and 42% may do so in the near future (Tarr, 2009). It is therefore worthwhile to document the DTA's energy impacts and estimate the energy savings resulting from the efficiency requirements established through NTIA and Energy Star. This information will also help demand forecasters as these units are gradually removed and replaced with digital televisions. To estimate these impacts, our study combines field measurements with NTIA data.
Section snippets
Origins of DTA performance levels
The rising energy use of set-top boxes (STBs) was first noted in 1997 (Harrison, 1997) and began to appear regularly in studies of energy use in homes thereafter. In 2001, STBs were recognized as an important contributor to standby power consumption in California and as an important target for energy-saving policies. The IEA convened a workshop in 2004 to address energy use of STBs. By that time, the first digital transitions of over-the-air television were underway in Berlin and Italy.
General
The goal of this study is to assess the effectiveness of energy efficiency standards applied to coupon-eligible DTAs, through power and energy measurements in home settings. The power consumption data collected are applied to an assumed usage pattern to generate an average annual energy consumption. This “policy case” annual energy consumption is then subtracted from a “reference case” annual energy consumption to estimate energy savings generated by the energy efficiency policies. The
Technical considerations
The 12 coupon-eligible DTAs measured in this study are listed in Table 1, together with information on the auto-power down feature, activity during Sleep mode, average On and Sleep mode power consumptions, and observed compliance with the NTIA coupon program and/or Energy Star. For Energy Star labeled products, manufacturers are required to test their converter boxes under specific test procedures for three different input signals and report the highest power values. Table 1 presents these
Analysis
The following analysis estimates energy savings generated by the NTIA coupon program, based on measured converter box power consumptions, baseline power consumption, and an assumed usage pattern. Because of the small sample size of DTAs measured and the short metering period, a representative usage pattern cannot be derived from the collected data. Instead, the usage pattern used to forecast energy savings for the Energy Star DTA program is assumed.
Table 3 summarizes the usage pattern
Conclusions
Among electronic products, DTAs are unique in that energy efficiency standards were implemented as part of a government assistance program before they became available in the US market. Based on our measurements of 12 DTAs that qualify for the NTIA coupon program, we found that the energy efficiency standards implemented on DTAs resulted in lower per-unit power consumption when compared to the baseline power consumption of 12–14 W. The high redemption rate of 35 million coupons indicates that a
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Cited by (1)
Energy savings opportunities in the global digital television transition
2017, Energy Efficiency