Resources | Roadmap | DoE | Technologies | SSL | Jun 15, 2015

DoE: Solid-State Lighting R&D Plan

The solid-state lighting (SSL) revolution signals a profound shift in how we will use and consider lighting and represents a huge opportunity to generate significant energy savings. The energy being used for lighting represents a significant portion of global energy use. Rising electricity prices, mounting concerns about climate change, and desire for energy independence are causing the global lighting market to shift toward more energy-efficient light sources.

In most regions of the world, even with government policy support, a small fraction, less than 10%, of existing lighting installations use SSL products. For example, Strategies Unlimited estimates that in 2014, light-emitting diode (LED)-based lamps comprised just 5% of unit sales and achieved 3% penetration of the installed base [1]. Nevertheless, they forecast dramatic growth in this market such that by 2020 LED- based lamps would comprise 42% of unit sales and represent 33% of the installed base. Other forecasts also anticipate extraordinary growth over the next 5 to 10 years. By any measure these are dramatic growth projections and present significant challenges for the industry. These challenges include further efficiency improvement, continued price reduction, manufacturing scale-up, and the integration of new value and features that can accelerate adoption and provide further energy savings. Addressing these challenges also offers the U.S. the opportunity to secure a dominant role in the technology and manufacturing of these products.

In the U.S., LED lighting is forecasted to account for the majority of installations by 2030, representing 88% of the lumen-hours being generated by general illumination [2]. The high efficacy of SSL sources is a critical factor in the drive for higher adoption. LED lighting is already as efficient, or more efficient, than most incumbent technologies, but there is plenty more to come. Using fairly conservative projections for performance improvements, the Department of Energy (DOE) has determined that by 2030, LED technology can potentially save 261 terawatt-hours (TWh) annually, a 40% reduction of the site electricity consumption forecasted for a counter-factual “no-LED”
scenario. Assuming the more aggressive projections, outlined in this report, can be realized through continuing investment in Research and Development (R&D), the total annual savings would increase to 395 TWh by 2030, a 60% reduction of the site electricity consumption [2]. This electricity savings corresponds to about 4.5 quads of primary source energy, which is nearly twice the projected electricity generation of wind power and twenty times that of solar power in 2030. At an average

commercial price of $0.10/kilowatt-hour, this would correspond to an annual dollar savings of about $40 billion [2]. However, in order to reach the performance levels assumed in this analysis, substantial improvements to efficacy and pricing are necessary. This underscores the importance of SSL and SSL R&D in any discussion of energy policy, due to its unprecedented opportunity to reduce energy consumption, thereby improving domestic energy security, and reducing greenhouse gas emissions.

The DOE has set some tough targets and fashioned its program to remove technology barriers and accelerate adoption. DOE support is essential to achieving the 200 lumens per watt (lm/W) luminaire efficacy program goal by 2020, reducing SSL manufacturing costs, and realizing huge energy savings. To achieve these goals and maintain the pace of development of the underlying LED and organic light- emitting diode (OLED) device technologies, the DOE advocates continuous focus on R&D. It is already apparent that improvements in LED package efficacy are becoming harder to achieve, and R&D is required to address fundamental technological barriers such as current efficiency droop and the need to develop new high efficiency, narrow line-width down-converter materials.

Still, SSL offers so much more than just improved efficacy. It represents a huge opportunity to improve the performance and value of lighting through enhanced controllability, new functionality, and novel form factors. SSL sources are inherently dimmable and instantaneously controllable; they can be readily integrated with sensor and control systems, thus enabling further energy savings through the use of occupancy sensing, daylight harvesting, and local control of light levels. SSL is at the heart of recent innovation in the lighting industry with respect to smart, connected, intelligent, and adaptive lighting. New functionality within the lighting system can create added value by providing optimal lighting for the occupants and the tasks being performed through real-time controls, programmed sensor-driven responses, or learning algorithms. The high speed modulation capability of semiconductor light sources has introduced new opportunities in the area of visible light communications, such as Li-Fi and indoor positioning capabilities. SSL offers the prospect of full color control over the light spectrum and will enable precise control over the delivery of light to reduce glare, reduce stray light, and optimize useful light. Control over the light spectrum is creating new opportunities in areas as diverse as horticulture and human health.

Understandably, most LED lighting technology to date has been engineered to address the near term market opportunities in the form of replacement lamps and retrofit luminaires. With an estimated 40 billion sockets in the world, these form factors clearly represent an enormous market and energy savings opportunity, but moving beyond these form factors will expand the concept of lighting and create entirely new lighting paradigms. Similarly, OLEDs offer a whole new approach to lighting based on their low illuminance, thin profile, and potential for surface shaping.

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