It can be challenging and expensive for electric utilities to balance supply and demand during peak periods, for example during summer-time heat waves in New York State. The utilities seek cost effective, automated, and reliable ways to reduce the demand (demand response) in order to avoid expensive generation plants, distribution and transmission infrastructure. Commercial building owners are considering ways to reduce electricity costs and curtail usage during times of peak electric loads. Lighting in many commercial buildings can be temporarily reduced to lower electric load without impacting productivity. Until recently, that strategy involved turning off banks of lights manually or through a complicated wiring system. The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute has released a new publication detailing field test results for a load-shedding ballast system for fluorescent lighting commercially available from OSRAM Sylvania. This system enables a building to easily and effectively step-down lighting, as needed during times of peak electric demand, without the need for costly wiring or wireless communications typical with more sophisticated lighting control system. The field tests were sponsored by the New York State Energy Research and Development Authority (NYSERDA), which supports projects that promote, design, and implement effective, energy-efficient lighting in commercial buildings.

Appearance, installation, and wiring of Sylvania’s load-shedding ballast are identical to standard, instant-start electronic ballasts. The load-shedding ballast replaces a conventional ballast in each luminaire. Operation is limited to T8 linear fluorescent lamps. The load-shedding ballast system was installed and operated at five sites in New York State and evaluated through LRC’s DELTA Program.
 
“The objective is to demonstrate how reductions in commercial lighting loads across multiple sites can have an impact on peak electric demands,” according to Jeremy Snyder, LRC’s Manager of Lighting Programs.
 
How the Load-Shedding Ballast System Works

The load-shedding ballast system includes load-shedding ballasts and a signaling device that sends a command to the load-shed ballasts on a circuit via the power line. In addition to manual activation, there are several manners the load-shedding can be automated, including use of a building management system, a timer, or connection to a curtailment signal from outside the building. Use of the load-shed system with a gateway can allow the system to response to a curtailment or price signal from a utility, ISO, or energy management service provider. For this field test, the load-shed systems in four demonstration sites were connected to the Internet with a simple, low-cost communication gateway device and signaled from a central server, as may be the case in a demand response program. The fifth site controlled the load-shedding ballast system using its building automation system.
 
When the load-shedding ballast system is activated, power to the T8 lamps is reduced by one-third, therefore reducing illuminance by one-third.
 
The LRC publication, Field Test DELTA: Demand-Response, Load-Shedding Ballast System, provides an overview of the load-shedding ballast system and discussion of field test results.
 
Study Findings

-Demand-reduction goals were achieved, confirming that the load-shedding ballasts operated as designed. Speed of the ballasts shedding response was near-instantaneous.

-Electricians characterized installation of the load-shedding ballast system as straightforward.

-Remote activation and feedback of the load shedding systems via the Internet operated as intended.

-Most building occupants indicated they had sufficient light levels to perform their assigned tasks. There was no significant change in the perception of lighting quality or quantity as related to performance.

-Specialized operations where illuminance levels are critical, such as precision machining areas, may not be suitable candidates for temporarily reduced lighting levels.

-The most advantageous economic outcome is a potential reduction in a customer’s demand billing.

-The load-shedding ballast system can provide a reasonable economic return for new construction as well as when replacing older T12 lighting systems. However, the economic return when replacing existing, efficient T8 lighting systems may exceed most customers’ economic criteria.

-The load-shed system is most economical in buildings with large numbers of high-wattage fluorescent fixtures on relatively few circuits.

-Key words: demand response, peak load reduction, smart buildings

-For complete details, access the Field Test DELTA: Demand Response, Load-Shedding Ballast System publication online at http://www.lrc.rpi.edu/programs/DELTA/pdf/DELTA-LoadShedBallastSystem.pdf.
 

DELTA Program

The DELTA program, sponsored by the New York State Energy Research and Development Authority (NYSERDA), was created to “Demonstrate and Evaluate Lighting Technologies and Applications.” The program has published a series of case studies evaluating lighting technologies in real-world environments including commercial, residential, retail, institutional, industrial, and outdoor applications. Most of the DELTA studies evaluate lighting products already available in the marketplace, while others, called DELTA Field Tests, evaluate lighting prototypes and independently verify claims and suggest improvements, when applicable. All DELTA publications are available at www.lrc.rpi.edu/programs/DELTA/publications.
 
About NYSERDA

NYSERDA, a public benefit corporation, offers objective information and analysis, innovative programs, technical expertise, and funding to help New Yorkers increase energy efficiency, save money, use renewable energy, and reduce their reliance on fossil fuels. NYSERDA professionals work to protect our environment and create clean-energy jobs. NYSERDA has been developing partnerships to advance innovative energy solutions in New York since 1975. Learn more at www.nyserda.ny.gov.