Intelligent buildings are highly autonomous and “think” on their own to operate at the highest-possible efficiency, create a comfortable and productive occupant environment, and facilitate the modernization of the electric grid. This intelligence relies heavily on the communication and exchange of actionable information across building systems, known as “interoperability”¹. Networked lighting control (NLC) systems can capture and share rich sensor data, and so interoperability is essential to unlocking the benefits that data can provide in intelligent buildings.

The applications that require interoperability are diverse, ranging from maintenance management systems with access to NLC fault and failure data, to streamlined work order dispatching, to enterprise applications which use occupancy status from NLC sensors to optimize space utilization. Each of these “use cases” has unique value propositions – achieving cost savings, improving operational efficiencies, increasing user satisfaction, or providing other organizational benefits. And each use case requires specific data to be shared among systems to enable the implementation and realize the value.

The DLC recently conducted a research study² to identify NLC interoperability use cases that have the potential to deliver high value to various stakeholders. This study, “Interoperability for Networked Lighting Controls,” broadly defined a catalog of 32 interoperability use cases and surveyed over 40 industry stakeholders to prioritize these use cases based on five key parameters:

• Energy / cost savings potential
• Occupant satisfaction
• Operational efficiency
• Anticipated market size
• Technical feasibility of being commercialized in 3-5 years

Based on this outreach, the DLC identified external Systems integration, load shedding/demand response, and energy monitoring as the three highest-potential use cases. The analysis focused on assessing the current status of and barriers to supporting interoperability and identifying necessary interventions to accelerate these three high-value interoperability use cases.

In the External Systems Integration use case, NLC data is made available to other building systems through an Application Programming Interface (API) for the purpose of improving their operational efficiencies. An example of this use case is sharing zone-level real-time occupancy status from NLC occupancy sensors with the Building Management System (BMS) through an API to control heating, ventilation, and air conditioning (HVAC) parameters in each HVAC zone, such as ventilation rate and thermostat setpoints. The BMS can roll up the zonal data to inform system-level controls and operations, including but not limited to chilled/hot water temperature reset and chilled/hot water flow rate reset.  

The Load Shedding/Demand Response (LS/DR) use case facilitates two-way communication between a grid-interactive efficient building and an electric utility or aggregator. The building communicates with the utility in order to understand utility needs, chooses whether and how to modify its power draw in order to meet those needs, and reports its modified behavior. Historically, DR programs have been focused on reducing peak demand to limit the use of expensive generation resources, and have been implemented by direct control, using one-way or very limited two way communication over time spans of days or hours. Today, utilities increasingly are planning to integrate renewable generation resources into their transmission and distribution infrastructure. The intermittent nature of these resources creates the need for additional “grid services” that go beyond simply reducing peak demand. These services are expected to require two-way communication to negotiate and/or estimate the response and the associated incentive. Further, these grid services may operate over time spans of days down to minutes or even seconds. Two-way communication and an ability to discern which lights could or should shed load at a particular point in time will be critical for lighting systems to participate in such grid service programs, provide significant value to utilities, and receive significant value (e.g., financial incentives) from participating.

In the Energy Monitoring use case, lighting energy data is reported by the NLC and shared with authorized entities with appropriate levels of detail and granularity. A specific example of this use case is the reporting of lighting energy data to a utility for incentive savings verification. A utility’s energy-efficient lighting program for advanced lighting controls requires the installed NLC to report the system-level energy usage at 15-minute intervals in a standard or well-defined format (such as Green Button) for the duration of one year. The energy data is transmitted to a repository provided by the utility over the Internet at a regular interval. The energy data from all program participants is used by the utility to verify the energy performance of incentivized systems and to calculate program-level energy savings, thereby facilitating a quantitative evaluation of program effectiveness and cost-benefit value.

What are the overarching gaps?

Realizing these use cases at scale will require bridging gaps in the following key areas:

• Clearly defining data requirements for each use case: The required data format and granularity, both temporal and spatial, has not been clearly articulated, specified and standardized.
• Developing projects to quantify the value of these use cases: More and larger projects need to be developed with a goal of quantifying the stakeholder value of these use cases and demonstrating the importance of sufficient and robust interoperability.
• Developing products with sufficient interoperability to deliver these use cases: Lighting systems are not currently developed and specified to facilitate use cases that require interoperability with non-lighting systems. Consequently, sharing data across systems and utilizing shared data is all too often a cost-prohibitive afterthought. 

How can stakeholders advance interoperability?

• Stakeholder leadership: The most effective way to bridge these gaps is for the stakeholder groups with the most to gain to assume leadership and drive the realization of specific interoperability use cases. For instance, utilities might incentivize and thereby drive the ability of NLC systems to share energy data for savings verification purposes. Utilities can further facilitate this use case by establishing an energy data repository and demanding automatic data intake as part of their incentive programs.

• Collaborative effort: Beyond the individual stakeholder efforts, supportive interventions for the interoperability use cases may be devised by a group of stakeholders with common interests. For example, trade associations with a vested interest in a specific use case can sponsor large-scale studies, and train and certify technicians that are specialized in implementing the use case.

• Policy-level impact: The best practices and quantified values identified through collaborative efforts can, in turn, serve as the basis for motivated stakeholders to influence the industry at the policy level. This includes developing interoperability standards and incorporating the interoperability use cases into building energy codes and green building programs.

This article is based on the report “Interoperability for Networked Lighting Controls” published by the DLC². The DLC NLC Technical Requirements Version 5 has also set a new focus on interoperability to facilitate capabilities that can support or meet the technical design criteria of the interoperability use cases discussed in this article and in the report.  For more information, read the full report or watch the recorded webinar about the research.

[1] Interoperability Profiles – A Better Way to Buy Grid Technology.  https://sepapower.org/knowledge/interoperability-profiles-a-better-way-to-buy-grid-technology/

[2] “Interoperability for Networked Lighting Controls” by the DesignLights Consortium. https://www.designlights.org/dlc-report/report-interoperability-for-networked-lighting-controls/