One result of the advent of solid-state lighting (SSL) has been the development of connected lighting systems (CLS), which are networked to share the data produced by LED drivers or collected from sensors. SSL technology, which is based on LEDs or organic LEDs (OLEDs), lends itself more readily and inexpensively than conventional lighting to being controlled – not just for light output, but also for such other characteristics as chromaticity and correlated color temperature (CCT). What’s more, SSL’s microelectronic nature facilitates the integration of sensors, network interfaces, and other functionality that can significantly reduce the energy consumption of lighting and other building systems, and also bring other benefits.
A connected lighting test bed
In 2015, the U.S. Department of Energy’s (DOE) SSL Program launched a CLS initiative that works closely with the lighting and information technology (IT) industries to foster a continuing and crosscutting dialogue on how best to prepare for and take advantage of the growing intersection between LED lighting systems and the Internet of Things (IoT). One aspect of this initiative is a connected lighting test bed (CLTB) facility, designed and operated by Pacific Northwest National Laboratory to characterize the capabilities of connected lighting systems. The results will increase visibility and transparency on key performance characteristics and new feature capabilities, and will create tight information feedback loops to inform technology developers of needed improvements.
Multiple indoor and outdoor connected lighting systems have been installed in the CLTB, and several studies are underway to characterize the energy reporting capabilities of connected lighting systems. One involves Power over Ethernet (PoE) connected lighting systems, which typically promise enhanced energy management capability, based in large part on the ability to report actual energy consumption; however, the accuracy of reported energy consumption, and which system components are responsible for it, are often unclear. Another study will inform collaborative efforts toward improved CLS interoperability by characterizing application programming interfaces (API) – highlighting what’s currently possible, tradeoffs, and lessons learned. A cybersecurity characterization capability is also being established in the CLTB in collaboration with Underwriters Laboratories (UL) and a variety of technology partners, as part of their effort to develop standard cybersecurity vulnerability test suites. DOE will share test results with UL and other Industrial Internet Consortium (IIC) partners, who in turn are supporting the DOE capability with hardware and software as well as test methods and general cybersecurity expertise.
Key focus areas
DOE’s efforts target some of the major hurdles to connected lighting:
• Energy reporting. Data-driven energy management can significantly reduce energy consumption and enable new market opportunities, such as pay-for-performance energy efficiency initiatives; energy billing for currently unmetered devices; verified delivery of utility-incented energy transactions (e.g., peak and other demand response); lower-cost, more-accurate energy-savings validation for service-based business models; and self-characterization of available (i.e., marketable) “building energy services.” But reporting accuracy must be known and meet the market opportunity requirements.
• Interoperability. System performance is dependent on the ability of devices to work together, and common platforms and protocols are needed to enable the exchange of usable data between lighting devices, other systems, and the cloud. Interoperability enables different devices, applications, networks, and systems to work better together. For users, it reduces the risk of device or manufacturer obsolescence, as well as the risk of having limited hardware, software, data, and service choices. It can also improve system performance by facilitating multi-vendor competition, reducing the cost of incremental enhancement and encouraging service-based deployment of complex technology.
• System configuration complexity. Systems that are overly complicated and time-consuming to configure have historically delivered less-than-ideal performance. This has often been the historical case with lighting controls, where the situation is compounded by a lack of standardization. As a result, significant energy savings are not being realized. Connected lighting systems with increasing degrees of automated configuration have the potential to significantly improve lighting system performance and increase its value. This, in turn, could lead to far more widespread use of lighting control strategies and greater energy savings.
Connected lighting’s ability to collect and exchange useful data, and possibly even serve as a backbone of the fast-emerging IoT, offers the potential to enable a wide array of services, benefits, and revenue streams that enhance the value of lighting systems and improve building systems that have long operated in isolation. In addition to occupancy and daylight sensors, other sensors that might be installed include, for example, those that measure carbon dioxide, vibration, and sound – resulting in such “smart building” or “smart city” benefits as air quality monitoring, theft detection, and guidance to available spaces (e.g., office, parking). While DOE is not involved in CLS to help realize those benefits and services, it fully appreciates how they can pay the freight for new CLS installations, thereby making possible very low-cost energy management controls.
But things are still in the very early stages. Broad-based collaboration among the lighting, semiconductor, computing, and IT industries is essential to realizing the full potential of CLS and needs to be facilitated in a variety of ways – including the development of key standards and specifications that enable interoperability, the establishment of collaborative real-world test beds, and the hosting of ongoing stakeholder meetings. To facilitate things, DOE hosts annual workshops (the last one took place in June in Santa Clara, CA) to provide a forum for the converging industries to examine key technology development needs. Stakeholder inputs at these workshops guide the development of activities at DOE’s connected lighting test bed as well as its R&D investments, and encourage the development of other CLS test beds, which increase the opportunities for stakeholders to see firsthand what’s possible and shorten learning cycles for technology developers. Interested parties should contact DOE at DOE.SSL.UPDATES@ee.doe.gov.
The IoT, which is coming on like a freight train, makes it possible for devices and systems to exchange data in order to improve their performance and offer new services and features. Replacing the conventional lighting infrastructure with SSL products not only facilitates connected lighting, but also brings the potential for lighting systems to become a platform for deeper energy savings.
