The Consumer Electronics Show in Las Vegas attracts a lot of attention these days because of the gee-whiz gadgetry that often debuts there. But the undercurrent of recent CES events has been the power needs of all those battery chargers and entertainment devices hooked into wall plugs. To borrow an old phrase from politics: A TV set here, a computer, there, and pretty soon you are talking about a real power drain.
Figures show that consumer electronics account for up to 15% of household electricity use. And despite efforts to minimize that amount, new gadgets could make the situation worse. In particular, the 3D TVs showcased in Las Vegas are potentially more power-hungry than conventional sets of the same size. The reason becomes evident from a quick review of how TVs generate 3D images.
As with most modern 3D viewing schemes, a viewer wears glasses containing liquid crystal display (LCD) shutters. Infrared sensors give the glasses a wireless connection to the TV. The TV creates the 3D image by alternating between two sets of the same image offset from one another by a small amount. LCD lenses in the glasses are synched to alternate between being transparent and opaque as the images alternate on the screen.
It is only recently that it has become practical to use LCD and plasma screens for 3D this way. The problem was that their refresh rates for screen images were too low. Viewers would have detected a flicker in the images which would quickly have become distracting. But now plasma and LCD displays operate at refresh rates (200 to 240 Hz) fast enough to handle 3D images with no distracting flicker. Unfortunately, these faster refresh rates come at the expense of additional power dissipation, which makes them the primary culprit for 3Ds' high power usage.
There are additional ancillary electronics associated with 3D TV that draw power. For example, the stereoscopic sync signal goes via a special port on a 3D-ready TV to an IR emitter. The emitter sends signals to the LCD glasses to synchronize them with the action on the screen. The generation of a 3D display also necessitates use of advanced CPUs, graphics processing units (GPUs) and memory circuitry. Moreover, consumers with the money to sink into a 3D TV are unlikely to be satisfied with a small screen; it is a given that 3D TV screens are large screens. And 3D TV electronics is destined to only grow more complex as these sets evolve with more features.
(Potential 3D TV owners should note that an easy way to view 3D content today is to stream it in from a computer to a 3D-ready TV. Expectations are that DVD players will eventually be capable of sending 3D signals to TVs.)
No question the extra power drain associated with 3D TVs has gotten the attention of energy specialists. The Lawrence Berkeley National Laboratory (LBNL), working on behalf of the International Energy Studies Group (IESG), thinks 3D TVs will use 1,200 GW-hr of electricity by 2014, a large percentage of that figure coming from 40-to 49-in.-diagonal TVs. (The IESG is composed of scientists in energy, forestry, and climate research.)
LBNL researchers point out that, in general, the high refresh rates needed for 3D TV reduce the amount of luminance available from these units to 60 to 80% of that from a conventional TV. Anecdotal evidence from TV manufacturers suggests that the minimum luminance level required for a user-perceived 3D-TV image is at least 90 cd/m2 while ordinary TVs can hit between 400 to 500 cd/m2. The reason: 3D-TV viewing glasses cut light levels from 500 to 90 cd/m2.
3D TV is getting attention because the associated energy use is not exactly trivial. Some TVs and set-top boxes consume as much as a home's biggest energy hog, the refrigerator. These devices can add more than $100 a year to a home's electric bill. And while the U.S. Federal Trade Commission (FTC) in 2010 dictated that retailers must put labels detailing annual electricity cost on the TVs they sell, as yet this practice isn't universal.
The interest in more energy-efficient TVs isn't just a U.S. phenomenon. The DoE is collaborating with governments of other countries on a contest for the world's most energy-efficient flat-screen TV. The motivation is that TVs comprise 6 to 8% of global residential electricity consumption.
The contest, part of an international initiative to promote super-efficient products, will award up to 20 Global Energy Medals to the most efficient TVs from four different regions: Australia, the European Union, India and North America. This initiative is part of the Clean Energy Ministerial.
But it's not as though TV energy consumption has been rising; TVs, in fact, have been getting more efficient. The power used by TVs globally dropped from 2003 to 2010 in both the active and standby modes thanks to more efficient TV designs. So says a report prepared by Darrell J. King and Ratcharit Ponoum of the technology development company TIAX LLC for the Consumer Electronics Association (CEA). TIAX measured American, European, and Japanese TV models.
The TIAX researchers found that most of the efficiency gains came in TVs' active mode. Power density for LCD TVs in the active mode dropped from 0.35 W/in.2 of TV screen in 2003 to 0.13 W/in.2 in 2010, representing a 63% decrease. For the standby mode, which is independent of TV screen size diagonal, consumption fell from 6.1 mW/in.2 in 2004 to 0.77 W/in.2 in 2010, an 87% decrease.
The same report found that plasma-display panel (PDP) TVs also did well in efficiency gains. They dropped from 0.22 W/in.2 in 2008 to 0.13 W/in.2 in 2010, a 41% improvement in the standby mode, and from 0.46 mW/in.2 in 2008 to 0.07 W/in.2 in 2010 for an 85% bump.
Connecting to the smart grid
TVs aren't the only opportunities for energy efficiency in the modern home. The DoE says lighting, refrigeration and cooking account for 41.5% of home energy consumption. And estimates are that 25% of each energy dollar spent in the home goes to heat water, even after prodding from DoE Energy Star Label regulations.
Regulators see the smart grid as an opportunity to further boost the efficiency of such energy sinks. That was one message from the Environmental Protection Agency's Katharine Kaplan, team leader for Energy Star product development, who spoke on connected appliances at this past January's International Conference on Consumer Electronics (ICCE). She sees a potential for saving 30% of the energy now used in many homes, buildings and similar facilities just by hooking home appliances and other consumer gear into the smart grid.
“The connected home is well on the way to becoming American culture,” she said. “New opportunities and business models are being brought to market through utilities, major retailers, cable companies, home security and automation providers and startups.” She emphasizes that adding smart grid connections to products such as home appliances can enable both energy savings opportunities and use of demand-response schemes, as well as provide new features that have nothing to do with energy use. “Sleep (mode) is good but products need to put themselves to bed in the future,” she adds.
The EPA is currently revising the Energy Star eligibility requirements for a variety of home appliances including refrigerators and freezers, dishwashers, and room air conditioners. Over 60 product categories in the U.S. are currently covered by the Energy Star rating, many of which are home appliances.
EPA staffer Amanda Stevens also addressed connectivity at a Demand Response Ready Technology Workshop sponsored by the Electric Power Research Institute (EPRI). She proposes the use of Smart-Grid-connected refrigerators and freezers with communication modules or similar capabilities for managing energy use via demand-response methods. With permission from consumers, utilities could make small adjustments in product operations that not only save money for consumers but also add big benefit for the electric grid as a whole. EPA thinks so much of this idea it wants to add a “connected” designation on the Energy Star Label for appliances that include this sort of enhancement.
Smart grid connections can also give consumers features that could, for instance, let them get feedback on how individual appliances use energy. Among the capabilities envisioned is the ability to access appliance energy use via mobile phone or tablet, so consumers could operate or schedule appliances to run while they are at work or travelling. Other ideas in the works are remote diagnostic functions that service personnel could use in lieu of making traditional service calls.
And smart-grid-based energy efficiency isn't only happening in the U.S. Researchers at Korea's Electronics and Telecommunication Research Institute (ETRI) are proposing a Green Home Energy Management System targeting energy consumption. ETRI claims the system can change user behavior by making available a comparison of energy usage among similar home appliances. In a nutshell, the system measures energy profiles for appliances in the home, which can then be compared with references on the system's server.
Finally, SEAD says the potential energy savings from its activities with its partners is large. It figures as much as 1,800 TWhours/year of electricity (as much as would be produced by 600 500-MW power plants) could be saved by 2030 through the efficiency measures it advocates for appliances. These measures include labeling programs like Energy Star, coordinating efficiency standards among major nations, and collaborating on the technical work necessary to devise useful standards.
What is SEAD?
To promote the international development of greater energy efficiency levels for home appliances and equipment, the Super-efficient Equipment and Appliance Deployment (SEAD) initiative was established by an organization called the Clean Energy Ministerial in 2010, which itself was a by-product of the climate change forum in Copenhagen earlier that year. Participating member countries include Australia, Brazil, Canada, the European Union, France, Germany, India, Japan, Korea, Mexico, Russia, South Africa, Sweden, the United Arab Emirates, the United Kingdom and the U.S.
Energy-related agencies in several countries collaborate with SEAD on various initiatives. For example the Global Environment Facility (GEF) has given SEAD $76 million for 24 projects promoting energy-efficient appliances in 27 countries. The International Energy Agency (IEA) is working with SEAD to ensure the quality of LED lighting products under IEA's 4E or “Efficient Electrical End-use Equipment” and Solid State Lighting (SSL) Annex directives.
Sweden will extend its collaboration with China on developing standardized testing methods for LED lighting in India and will coordinate with SEAD partners through the IEA's 4D SSL Annex.
An organization similar to SEAD is the Consortium for Energy Efficiency (CEE), which covers North American energy efficiency work. CEE members collectively spend about $6 billion annually in the U. S. and Canada for energy efficiency programs. CEE is in active discussions with the U.S. DoE to reach a cooperative agreement with SEAD to advise and participate in SEAD-led efforts.
TIAX LLC, Power Consumption Trends in Digital TVs Produced since 2003, http://www.ce.org/PDF/PowerConsumptionTrends.pdf
CSA International, Energy Star testing services, http://www.csa-international.org/product_areas/energy_efficiency/
Super-efficient Equipment and Appliance Deployment (SEAD) Initiative, www.superefficient.org
EPA Energy Star page on TVs, http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=TV
Korean Green Home Energy Management System, http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5973168
The Global Environment Facility, www.thegef.org
The International Energy Agency, www.iea.org
The Consortium for Energy Efficiency, www.cee1.org
The Regulated Multi-State DSM Programme, www.elcomaindia.com
The International Partnership for Energy Efficiency Cooperation, www.ipeec.org