How Much More Energy do Ultra High Definition and Smart TVs Use? Noah Horowitz Natural Resources Defense Council (NRDC) David Cadier, Chris Calwell, and Gregg Hardy Ecos Research Abstract The transition from standard definition to high definition TVs threatened to greatly increase energy use, but minimum efficiency standards, labeling, and utility incentive programs helped encourage widespread adoption of better backlighting, optical films, automatic brightness control, and other technologies to offset those increases. The transition to ultra-high definition (UHD) represents a second, equally compelling threat to energy consumption and opportunity for energy savings. Our testing of new U.S. models in retail stores and the laboratory confirms enormous variation in energy use among models of similar size, and highlights technologies and design strategies common to the best and worst products. High dynamic range (HDR) capability, always-on smart TV features observed in some models, and the steady shift to larger screen sizes represent the greatest upward pressures on TV energy use. We urge policymakers to adopt changes to test procedures and energy efficiency specifications to better anticipate and respond to this important shift in television technologies and capabilities. Introduction In 2013, televisions (TVs) in the United States (U.S.) consumed approximately 50 billion kwh/yr. according to a Consumer Electronics Association sponsored study [1]. This is equivalent to the annual output of 17 average (500MW) coal burning power plants. These TVs cost consumers $6 billion per year to operate and were responsible for 28 million metric tons of annual CO 2 emissions. On average there are 2.5 TVs per U.S. household. This level of consumption is higher than it was in the era of CRT-based, standard definition televisions, primarily because of the growth in total number of TVs in use, average hours of operation per day, and average screen size. However, total TV energy use is much lower today than originally projected with digital TVs, in part because of a concerted global effort by policymakers to test television energy use in a standardized way, set minimum energy performance standards (MEPS) to eliminate the least efficient models from the market, label TVs according to their energy efficiency, and promote the best products with financial incentives in some jurisdictions. Indeed, the progress made over the last seven years improving television energy efficiency rivals the achievements recorded with refrigerators over a longer period of time. The transition now underway to ultra high definition (UHD) threatens that record of steadily increasing energy savings for a number of reasons: UHD TVs have four times as many pixels as HD TVs, increasing screen opacity and typically requiring brighter, more power consumptive backlights to deliver equivalent image brightness to the user. (UHD TVs typically have a resolution of 3840x 2160, which is commonly referred to as 4K). Global shipments of UHD TVs are expected to rise from 12.1 million units in 2014 to 100 million by 2018 according to recent forecast by Strategy Analytics [2]. Manufacturers and retailers are aggressively promoting larger screen sizes as a way to ensure that the higher resolution of UHD TVs is visually apparent to users. Smart TV capabilities associated with internet connectivity have become nearly ubiquitous in UHD TVs, increasing processing and networking power and the likelihood that they will remain connected after users have switched their televisions into a low power mode.
4K resolution, high dynamic range (HDR), wide color gamut, high frame rate, and enhanced audio capabilities associated with the new UHD Blu-Ray standard and associated streaming standards collectively have the effect of dramatically increasing the rate at which digital data flow into televisions. This, in turn, tends to increase the power TVs consume to process and render that information to users. The higher contrast ratios and more vividly saturated colors will improve the TV viewing experience, but increase energy use accordingly. In order to better understand the energy impacts of some of these new features, the Natural Resources Defense Council (NRDC) retained Ecos Research to perform basic in-store testing of a cross section of 2014 and 2015 models with laboratory grade equipment and more comprehensive testing of 11 different 2015 models in the laboratory. The testing focused on models with a 55 inch screen size, as these represent a very popular, affordable price point for fully featured UHD TVs available on the US market today. We did not test smaller UHD TVs, like the 42 inch models which are very popular in the HD marketplace, as most viewers would not be able to observe the UHD resolution benefits under normal viewing conditions. Our main areas of focus were to understand the On mode power used by UHD TVs and the impact of Smart TVs and their internet connectivity on standby power. The specific research questions the study was designed to answer include: Do UHD TVs consume more power than similar sized full HD TVs in active mode? Is there a wide range in the On mode power levels among various UHD TV models of the same size? What impact does the automatic brightness control (ABC) feature have on measured On mode power? What impact does the resolution or source of the incoming content have on On mode power: is there any difference when receiving HD vs UHD content? Or when receiving UHD content via streaming vs from a disc played on an upscaling Blu-ray player? What are the Standby power and boot times for Smart TVs with Quick Start feature enabled and disabled? What issues, if any, were identified regarding the official test methods used to perform the measurements? Testing and Sampling Plan Our research had three components: a) review and analyze public databases of TV energy use managed by the California Energy Commission (CEC), ENERGY STAR program, and the US Department of Energy (DOE); b) perform in-store testing of selected 2014/2015 UHD models; and c) perform laboratory testing of selected 2015 UHD models. Our in-store testing allowed us to gather data without having to purchase the TVs, many of which were newly introduced at prices of $3000 or more. As we were unable to control the ambient lighting levels in the store, the in-store testing was done without the TVs automatic brightness control (ABC) enabled. The results of our in store testing informed the models we would purchase and test in the laboratory, which included testing TVs with ABC enabled. The focus of our testing was on UHD TVs that ranged between 50 to 65 inches in diameter, with attempts to purchase 55 inch models whenever available to allow for comparisons among similar sized TVs. Due to budget constraints, we performed testing on a total of 21 TVs, roughly half in-store and half in the laboratory. In addition to this testing, we also analyzed the above databases to understand how the manufacturer reported energy use of the top four brands (Samsung, LG, Vizio, and Sony) of TVs in the 50 to 60 inch range varied between HD and UHD models, and between model years 2014 and 2015. A listing of each of the 11 models to be tested in the laboratory along with details on the TVs features and the results of our On mode power measurements is presented in Figure 1. In deciding which models to test, we tried to select a broad cross section of models by choosing multiple brands, and a range of display technologies and operating systems to understand which variables have the greatest impact on On and Standby mode power consumption. Many new models shown at the Consumer 2
Electronics Show (CES) in January 2015 were released to the market later than expected, so testing of the low-priced Hisense and Spectre models and the newest Panasonic model with always on voice recognition is still in-process and their results are not yet reflected in our findings. This article reflects the testing performed to date and will be updated once the testing of the remaining three models is complete. All laboratory testing of on mode power use was performed in accordance with the DOE test method [3] which utilizes a set of dynamic test clips from the IEC and static test patterns on a Blu-Ray disc that has been incorporated into testing standards around the world. Use of standardized content is important, as on mode power can vary significantly depending on the colors and average picture level (APL) of the images being displayed. In addition to following the setup instructions defined by DOE, we then performed additional testing with certain features enabled or disabled to understand what impact that might have. For example, if a Smart TV shipped with Quick Start disabled, we tested it this way for official testing and reporting purposes and then also tested it with that feature enabled to gather data on what impact it would have on start time and Standby power use. Similarly if a TV was shipped with ABC on, we tested the TV a second time with ABC disabled. For both lab and retail testing, a stable AC waveform was provided to the TV using a Chroma 61602 reference power source. Real time power analysis and data logging was performed using a Yokogawa WT-310 analyzer interfaced to a custom LabVIEW software interface. Test equipment and tolerances were configured per the DOE/IEC standards and a sample rate of 250ms was used for all measurements. During ABC testing, room illuminance was measured using a Konica T-10A meter. All test equipment held valid calibration certificates at the time of test. Because the IEC test disc and all content available on Blu-Ray disc still has a maximum resolution of 1080p, we utilized an OPPO Blu- Ray player to upscale that content to 4K or streamed native 4K content from the internet in other cases to better understand the incremental energy consumption associated with that capability. Within the test methods, there are multiple low power modes corresponding to varying levels of processor activity and power consumption. Standby-passive is the lowest level of standby whereby the TV is not able to send or receive data, and standby-active low is the state where an internet connected TV is capable of receiving or sending data. When a TV is in standby and actively receiving or sending data, such as updating an App or receiving a firmware update, it is in standby-active high mode. Our testing did not include standby active high mode, given its typically brief duration within an overall annual duty cycle of operation. (Note during testing of the Sony 2015 model, it is unclear whether the TV was in standby-active low or standby-active high mode.) Testing Results and Observations All in store and laboratory testing was performed between April and June 2015. A description of each of the 11 models purchased for laboratory testing is provided in Figure 1 along with the results of our On mode power testing. To be determined (TBD) is shown in the entries for the three models where testing has not yet been completed due to their delayed availability on the market. Figure 1: Specifications on the Models Purchased for This Study and Their Measured On Mode Power Levels Spread in Power Use of UHD TVs Tested and Comparison to ENERGY STAR Specifications In addition to performing testing of the models listed in Figure 1, we analyzed the manufacturer reported On mode power from the aforementioned public databases of TVs in the 50 to 60 inch 3
screen size category for the top four brands sold in the US Samsung, LG, Vizio, and Sony. We plotted the On mode power data from the databases and our measured values alongside the maximum allowable power curves from the U.S. Environmental Protection Agency s (EPA) ENERGY STAR labeling program. EPA s goal is to have its specifications represent approximately the top 25% of the market in terms of their energy efficiency when the new levels go into effect. ENERGY STAR Version 6 went into effect in June 2013 and the latest Version 7 goes into effect on October 30, 2015. In Version 7, EPA created separate requirements for HD and UHD models and provided a roughly 50% additional On mode power allowance or adder for UHD models. Some observations from Figure 2 include: a) There is a wide spread in the On mode power use of UHD models of equivalent screen size, sometimes by more than a factor of 2. b) There are already many UHD models that are well below the UHD qualifying level for ENERGY STAR Version 7, several months before its effective date. c) There are already a few UHD models on the market that meet or just exceed the ENERGY STAR Version 7 level for non-uhd models. Figure 2: UHD TV On Mode Power Use Compared to ENERGY STAR Curves FigureFigure 3 shows how the annual energy consumption (AEC) levels in kwh/yr vary for the 55 inch model TVs that we tested in the laboratory. AEC was calculated using the DOE specified daily duty cycle of 5 hours On mode and 19 hours Standby mode. The AEC levels ranged from a low of 110 kwh/yr to a high of just over 300 kwh/yr. At a national average electricity rate of 12 cents per kwh, this incremental power use translates to an extra $228 in utility bills over the ten year life of a new 55 inch TV. 4
Figure 3: Range of Annual Energy Use of 55 inch TVs Tested in the Laboratory Figure 4 provides a detailed look at the reported On mode power levels of UHD models in the public databases. The data set included 151 UHD models in 2014 and 189 UHD models in 2015. Above 60 inches, TV power use of the least efficient models rises dramatically. Some of these more power consumptive models can easily use as much energy per year as a typical refrigerator sold in the US. It is also evident that some of the most power consumptive models are so far away from qualifying for ENERGY STAR specifications that their manufacturers may not bother making small refinements in their design to improve energy efficiency. Adoption of MEPS by jurisdictions around the world could be an effective means to remove the worst models from the market. Figure 4: Reported On Mode Power Use for TVs 50 Inches and Greater 5
Measured Impact of Automatic Brightness Control on On Mode Power TVs with the ABC feature contain a sensor that automatically measures the level of light entering the front of the TV and adjusts the picture brightness accordingly. The concept behind this feature is that TVs watched in a darker room do not need as bright a picture and that automatically reducing the brightness of the TV s backlight brings down the TV s On mode power use. Per the DOE test method, TVs that are shipped with ABC enabled and do not offer the user a choice to turn off this feature during the initial set up are tested with ABC on. If the TV is shipped with ABC disabled or provides the user a choice to disable it during the initial set up, then the TV is tested with ABC off. For testing done with ABC on, power measurements are made at four room illuminance levels 3, 12, 35, and 100 lux and the reported On mode power is the average of these four values. In our laboratory testing of 55 inch models we found that the UHD TVs used an average of 57% more power with ABC off than with ABC on. The range was from 17% to 93%. For each model tested, the On mode power value that would be reported per the DOE test method is the bar that contains the white text in Figure 5.The difference in On mode power levels between ABC on and off was the biggest for the Vizio and LG models. The Vizio model defaults to ABC off and LG users are presented a choice in the forced menu during initial TV setup. The Sharp model was the only TV we tested that did not have an ABC feature. A closer look at the values in Figure 5 for the Vizo and LG models shows that a single change in how companies design their set up screens and implement ABC can dramatically reduce a model s reported On mode power use and in some cases result in their qualification for ENERGY STAR. In addition manufacturers would be able to report a much more competitive energy use value on the yellow Energy Guide label that compares model energy use and annual operating cost to other similarly sized models sold in the U.S. market. Figure 5: On average, 55 inch UHDs use 57% more power with ABC off It also noteworthy that the European Union s eco-design requirements treat ABC very differently as TVs in Europe are tested with ABC turned off and limits the credit a TV with the ABC feature can receive to just 5%. Below is the excerpted text from the EU regulations No 1062/201 [4]. For the purposes of calculating the Energy Efficiency Index and the annual on-mode energy consumption the on-mode power consumption as established according to the procedure set out in Annex VII is reduced by 5 % if the following conditions are fulfilled when the television is placed on the market: 6
a) The luminance of the television in the home-mode or the on-mode condition as set by the supplier, is automatically reduced between an ambient light intensity of at least 20 lux and 0 lux; b) The automatic brightness control is activated in the home-mode condition or the on-mode condition of the television as set by the supplier. As such, care should be used when comparing reported On mode power levels reported in the US and the EU. It would also be interesting to investigate whether models shipped to Europe are less likely to come with ABC feature than those in the US given the much smaller impact this feature has on the reported On mode power level. Impact of Receiving HD or UHD Content or Input Method on Measured On Mode Power Although there has historically been minimal availability of native 4K content, its availability is increasing as Netflix, Amazon, YouTube, and other streaming services have begun supporting it and UHD Blu-Ray standards have been finalized for implementation later this year. Today s UHD TVs upscale or up-convert incoming HD content to their screens native 4K resolution. It is not known how UHD On mode power use would change if the TV receives native UHD signals. One might assume the measured power values would be lower as the TV does not have to perform the processing to upscale the signal. Alternately, some TVs might boost the screen brightness levels when displaying native UHD content. In an attempt to assess this issue, our testing included two On mode power tests of the IEC test clip on an OPPO Blu-ray player. For the first test, the signal received from the Blu-Ray player had a resolution of 1080i, which was then up-converted by the TV to 4K, and for the second test the signal was up-converted in the player to 4K and sent to the TV. To ensure consistent testing results, all of the testing was done with ABC disabled. This testing was done in the store and the models shown include both 2014 and 2015 models, and most are different than those we purchased for laboratory testing. Figure 6 shows that on average the tested UHD TVs used 10% more power when displaying native 4K content compared to HD. One particular outlier is the Samsung 65JS9500 UHD TV we tested that showed a 46.8% increased On mode power level when displaying 4K content. Given the size of this difference, and the fact that the JS9500 represents the most fully featured and favorably reviewed new model of its size, it would be worth exploring this model s performance further. Figure 6: Comparison of On Mode Power Use When Displaying Native 4K vs HD Content 7
Separately we examined the impact that the signal source had by comparing the On mode power used when streaming a movie vs when played on disc. To perform this comparison we used a 10.5 minute clip from the movie Crouching Tiger Hidden Dragon and tested the power levels when a 4K signal was received via streaming over Netflix and by playing the same clip from a 1080p disc that was up-scaled by the Blu-ray player to 4K and then fed to the TV. Figure 7 shows the relatively small impact that internet streaming had on most of the TVs that were tested. Again, all of these tests were run with ABC off. Figure 7: Comparison of On Mode Power Use - 4K TV Content from a Disc vs Streaming Standby Power Levels of Internet Connected TVs ( Smart TVs ) The majority of TVs sold today can access the internet wirelessly or via Ethernet connection without the use of a Roku box, Google Chromecast, Apple TV or similar external device. TVs with this functionality are generically referred to as Smart TVs. Their internet connectivity allows consumers to stream movies via applications such as Netflix on their TVs and to search the internet for YouTube videos and other content. Some of the first Smart TVs had boot times, the time needed for a TV to restart from off and re-establish a live internet connection, of 15 to 30+ seconds. As a result, some manufacturers added a Quick Start feature which reduced the boot time, but caused a big jump in a TV s standby power. In the first versions of Google TV that were incorporated into Sony s initial Smart TVs, the standby power with Quick Start selected was 24 W. At 19 hours per day, the Standby energy use alone would be 166 kwh/yr., which could result in a doubling of the TV s total annual energy use. In their 2015 models, manufacturers have increased the number of applications available for use on Smart TVs, updated the underlying software and hardware, and are heavily promoting these capabilities. To better understand how boot time and standby power use levels vary with and without Quick Start selected, we tested a range of 2014 and 2015 models. The results of this testing are shown in Figure 8. Boot times of less than 10 seconds and standby power use of <0.3 W were observed for the Samsung and LG models. The Vizio models tested had a very low standby power level as well, 0.2 W, but had slightly longer boot times of 15 seconds. At the other extreme were the Sony and Sharp models which had much higher standby power levels when Quick Start was selected. The 2014 and 2015 Sharp models tested with Quick Start on had standby power levels and boot times of: 25.2 W 8
and 8.9 seconds, and 9.3 W and 5.7 seconds, respectively. Without Quick Start selected, these TVs had boot times of 19.5 and 17.9 seconds, which are longer than what some consumers may find acceptable. As such, many consumers are likely to go into the menu at a later time and select the Quick Start setting which could result in 62 extra kwh/yr. of standby energy for the 2015 Sharp model. Per the test method, this significant additional annual energy use would not be captured in this case with the Quick Start feature disabled. Figure 8: Standby Power Levels and Boot Times for Smart TVs With and Without Quick Start Selected When Quick Start was selected for the 2014 Sony models, the TVs drew a whopping 34.4 and 37.5 W in Standby power. However, the TVs had some additional software that would limit this high standby power to 6 hours per day, or allow the TV to learn the user s viewing times and reduce the hours which Quick Start was on and drawing these high power levels, accordingly. Figure 9: Variation of Measured Standby Power Use Over Time of Sony Model The 2015 Sony Model 850 C had a measured boot time of 8.2 seconds, which is probably low enough for most users, and did not have a Quick Start option. As the power used in standby was cycling and did not stabilize, we left the power meter engaged for an extended period to record the unit s standby power use. As seen in Figure 9, the standby power cycled between 0.29W and 22.1W for a period of 9
4 ½ hours, at which point it then stabilized at 0.29W. The average power draw during that cycling period was 7.6 W, which translates to 12.8 kwh/yr. per cycle. This occurred each time the TV was turned on and off, meaning its contribution to annual energy use could be even higher if users watch TVs in multiple, short intervals spread throughout the day. For some users, the standby energy use would be three times this amount or 38.4 kwh/yr. if they have a usage pattern whereby they turn on the TV before work, a child watches TV or plays a video game during the early afternoon, and the parents watch TV in the evening. Conclusions and Recommendations The key findings from our research are: On mode power for the 55 inch diameter UHD TVs we measured varied widely, sometimes by more than double. Some models were very efficient and use little to no incremental power than similar sized HD TVs, while others use a lot more power. Above 60 inches, On mode power use of the least efficient models increased dramatically. This could result in big increases in national energy use should these large TVs gain in popularity as their costs continue to fall. 70 UHD models are now available in the US market for just under $2,000, and 80 UHD models have reached price points of $4,000 to $5,000, where they were previously unavailable at all or only sold for $20,000 or more. Automatic brightness control (ABC), when enabled, can dramatically reduce a TV s annual energy use. For the 55 inch models we tested, we found UHD TVs used 57% more power with ABC off compared to ABC on. Testing of more models, including those of different sizes is needed to better quantify the impact enabling ABC has on On mode power levels. Some but not all of the manufacturers have successfully achieved boot times of <10 seconds and standby power levels of 0.3 Watts or lower for their Smart TVs. Others had extremely high Standby power levels, the worst being a 2014 model that consumed 25 Watts continuously when Quick Start was selected. That translates to an incremental annual energy use of 174 kwh/yr. One manufacturer s TV cycled continuously between 0.3 and 22 Watts when in standby for a period of 4.6 hours after the TV was turned off, which translated to an average standby level of 7.6 Watts during that period. UHD TVs drew on average 10% more On mode power when receiving native 4K content instead of 1080p content during testing. There was little difference in On mode for TVs that received 4K content via streaming vs from an upscaling Blu-ray player. Based on our learnings from this research we recommend: 1. Interested parties should obtain access to model-specific market share data and calculate the difference in energy use between HD and UHD models of similar size, and how UHD energy is changing from year to year. This data can also be used to estimate the impacts of high adoption of UHD TVs in terms of their energy use, electricity bills and CO2 emissions from power plants. 2. Policy makers should also carefully track the market share of larger TVs given its potential impact on national TV energy use. 3. Manufacturers whose models have an ABC sensor should ship these models with this feature enabled by default and without requiring its selection in the forced menu. This one easy change can dramatically reduce the amount of energy consumed by these models 4. EPA should carefully review UHD On mode power levels of the latest 2015 models and reduce the size of the UHD adder in its update to ENERGY STAR Version 7 accordingly. 5. California and other jurisdictions should adopt MEPS that extend coverage to all sizes of televisions and that reflect the emerging reality that new UHD features can increase TV energy consumption, but do not need to increase it by nearly the extent observed in the least energy efficient models. 10
6. Changes to the test method that will increase its reproducibility and accuracy include: a) Clarify how to measure average Standby power for Smart TV models that seem to fluctuate between standby-active low and standby-passive modes. Rather than waiting for the value to stabilize before measuring it, there may be merit to measuring it from the moment the TV is first switched off until it has stabilized to a nearly constant value for at least one hour and then reporting the weighted average power value for that entire period. b) Consider requiring models whose reboot times exceed 10 seconds to be tested with Quick Start selected since that is how many consumers may ultimately operate it. c) Re-master the IEC test clip to provide native 4K content with HDR encoding by the end of 2015 to enable more accurate measurement of TVs with those capabilities in the future. Also use representative real world content that does not contain blinking between discrete scenes which occurs in the current IEC test clip and could lead to gaming by a smart TV manufacturer whereby the TV detects that it is being subjected to the energy test and alters its performance in order to deliver a lower, more favorable power use value. 7. Conduct preliminary testing of HDR-capable TVs with High Dynamic Range (HDR) content to better quantify the resulting energy consumption impacts. References [1] Urban B., Shmakova V., Lim, B. and Roth K. Energy Consumption of Consumer Electronics in US Homes in 2013. Final Report to the Consumer Electronics Association: June 2014. Can be downloaded at: http://www.ce.org/corporatesite/media/environment/energy-consumption-of- Consumer-Electronics.pdf. [2] Watkins D. Ultra High Definition TV Displays: Global Market Forecast. Report by Strategy Analytics: February 27, 2015. Can be downloaded at: http://www.strategyanalytics.com/default.aspx?mod=reportabstractviewer&a0=10660. [3] U.S. Department of Energy. ID: EERE-2010-BT-TP-0026-0076010-BT-TP-0026-0076. Energy Conservation Program: Test Procedures for Television Sets; Final rule. October 25, 2013. Can be downloaded at: http://www.regulations.gov/#!documentdetail;d=eere-2010-bt-tp-0026-0076. [4] European Commission. Commission Delegated Regulation (EU) No 1062/2010 of 28 September 2010 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to energy labelling of televisions, Official Journal L 314/64, 30.11.2010. Download and go to Annex 2 at: http://eur-lex.europa.eu/legalcontent/en/txt/html/?uri=celex:32010r1062&from=en. 11