How Lighting Controls Improve Microgrids

By Andy Wakefield, Lutron Electronics

The Challenge

The Smart Grid, a reference to the modernization of the national electricity supply system, is an automated electric power system that monitors and controls grid activities, ensuring the two-way flow of electricity and information between power plants and consumers—and all points in between.

What makes this grid smart is the ability to sense, monitor, and, in some cases, control (automatically or remotely) how the system operates or behaves under a given set of conditions, including weather events that cause power outages, national emergencies, or even malicious security threats such as hacking or potential cyber attacks. In its most basic form, implementation of a smarter grid is adding intelligence to all areas of the electric power system to optimize our use of electricity.

As the national electrical grid shows increasing signs of instability, the interest in independent, reliable microgrids increases. At their core, microgrids work to reduce reliance on an increasingly frail external power supply and improve energy reliability.

And, while there are significant advantages, there are risks associated with microgrids, such as vulnerability to energy fluctuation. Unusual demand may overwhelm the system, putting critical operations at risk, but existing concepts and technologies including high performance building systems, microgrids, and energy storage can ensure that facilities are more secure, reliable, and efficient.

The need to better manage the electrical grid is driving smart grid implementation, but commercial buildings do benefit from energy management strategies.

• Receive financial incentives from demand response programs and by managing peak demand
• Use less energy and spend less money
• Reduce building electrical usage at critical periods to prevent grid instability, blackouts and critical peak charges
• Reduce load at the touch of a button or automatically without having to dispatch the maintenance team to manually turn off loads
• Shed electric load without disturbing the occupants of a space
• Help stabilize local community energy prices
• Take advantage of potential rebates and additional government incentives
• Avoid excessive peak charges

The Solution to Ensuring Supply and Reducing Demand

Microgrids rely on both energy generation and energy reduction to maximize efficiency and minimize risk. As an energy reduction strategy, lighting control systems work to make microgrids more reliable, and support energy-saving and sustainability goals.

Lighting control systems, when properly planned and implemented, can create significantly greater flexibility within a microgrid. Preset lighting scenarios can be programmed to react to a variety of crisis situations.

For example, in an office building, one scenario may increase lighting levels in open office areas, maintain full lighting power in a medical facility, and ensure lighting to emergency exits, while reducing light levels in common areas, cafeterias, or perimeter areas with access to natural daylight areas. Balancing lighting energy helps to assure the efficacy of the microgrid’s power supply.

Lighting Control Facilitates Load-shed Strategies

Load shed, or the ability to quickly reduce electricity use during peak periods, is critical to ensuring microgrid reliability. Because lighting uses a considerable proportion of building peak electrical loads (30% of peak electricity),¹ and because reduced light levels deliver immediate reductions in electricity, lighting control is one of the simplest and most predictable demand response solutions.

The reduction of lighting load also provides a reduction in HVAC cooling load during the summer, which is the most common peak electrical period.  Furthermore, since dimming is typically unobtrusive when it is executed over a period of time (as little as 10 seconds), lighting control is a viable option for immediate emergency response.

Dimming as a load shed strategy is highly effective because the human visual system has the ability to accommodate a wide variety of light levels with minimal effect on the occupants^2,3.  When a demand reduction is required a gradual dimming of electric lighting can reduce light levels by 35 percent before 20 percent of the occupants attempt to intervene.  Response time is essentially instantaneous, typically has little impact on occupant comfort, and demand savings from lighting are more predictable than those from HVAC response.

Light management systems have the capability to automatically trigger a demand response event from a utility signal or from time clock scheduling. Therefore, a predictable and effective demand response strategy can be automatically implemented while going virtually unnoticed to the building occupants.

Energy codes, standards, and green building certifications such as ASHRAE (American Society of Heating, Refrigerating, and Air Conditioning Engineers) 90.1, IECC (International Energy Conservation Code), California Title 24, ASHRAE 189, IgCC (International Green Construction Code), or LEED (Leadership in Energy and Environmental Design) now include lighting controls as a part of a whole-building energy strategy.

There are subtle differences for each code/standard/certification, but some general requirements and/or credits include: required lighting control for most areas (manual or automatic), automatic lighting shut-off, some automatic receptacle shut-off, daylight controls for daylit spaces, automatic shut-off of exterior lighting during daytime hours, and various levels of occupancy/vacancy control. As a result of buildings updating their basic lighting control infrastructure to meet code, they are increasingly becoming capable of connecting to a microgrid, without the need for additional significant investments.

Energy-efficient Lighting Helps Make Microgrids More Reliable

Lamp efficacy has traditionally been the focus of lighting energy savings. As lighting sources approach maximum efficiency, it is clear that the next big steps in lighting energy savings will come from smart control solutions that automatically work to reduce lighting energy use, and ultimately to help microgrids support energy-efficient, cost-effective, environmentally friendly buildings.

1. Rubinstein F & Kiliccote S.  2007.  Demand responsive lighting: a scoping study.  Ernest Orlando Lawrence Berkeley National Laboratory.
2. Newsham GR & Mancini S.  2006.  The potential for demand-responsive lighting in non-daylit offices.  National Research Council Canada.
3. Newsham GR & Birt B.  2010.  Demand-responsive lighting: a field study.  National Research Council Canada.

Andy Wakefield is director of government and OEM solutions at Lutron Electronics. This article originally appeared in ei, the magazine of the electroindustry, published by the National Electrical Manufacturers Association (NEMA).