An Introduction to Dimmable Ballasts: Benefits, Strategies, and Incentives

Dimmable fluorescent ballasts were highlighted in a case study during a recent Customized Solutions training webinar. Since then, the Authorized Participant Technical Support team has received many inquiries about the technology. In this short article, we'll provide an introduction to dimmable ballasts and the incentives available to support implementation.

Dimmable ballasts are a type of transformer that can be used to alter the light output level of fluorescent lamps. With most electronic dimming ballasts, light levels can vary between full output and a minimum of 10%. There are several types of dimmable ballasts, but the most common alter the output power to the lamps based on a signal sent on a low-voltage control network. This control network may be added during a building renovation or, in some circumstances, during a lighting retrofit.

Installing dimmable ballasts in place of standard ballasts offers several opportunities to save energy:

• Tuning the maximum light output: Many lighting systems provide more foot candles to a space than its occupants require. By permanently reducing the maximum ballast output power by 20%, you can often achieve significant savings while maintaining occupant comfort.
• Integrating with occupancy sensor control: Instead of a simple on/off occupancy control, dimmable ballasts allow lighting fixtures to maintain a minimum lighting level for safety and security considerations. While energy savings are not as high as compared to an on/off control, the dimmable ballast strategy may be more advantageous for certain spaces or clients with security lighting, stairwells, and parking garages.
• Integrating with photosensor control: Daylighting control, also known as daylight harvesting, is fast becoming the norm for many new construction projects, but can also be implemented as part of a retrofit project. Light output from the fixtures in a lighting zone is reduced as photosensors detect increasing natural light from windows, skylights, and/or light wells.
• Integrating with demand-response control: SCE works with many of its customers to reduce power demand during periods of high energy demand. During these demand events, the utility will send a control signal to dim the light output to a pre-established level. The customer receives an annual incentive for enrolling in the program and another incentive for each event, which generally lasts only a couple of hours.

Not all four strategies will be optimal for all spaces, but each can be used in conjunction with any combination of the others to achieve deeper savings for your customer. It is important to remember that each of the control strategies described will require commissioning to ensure that they are operating as intended and meet the occupants' needs. The California Advanced Lighting Controls Training Program (CALCTP) offers free of cost training and certification for electricians who install and commission these types of advanced lighting controls. See the side bar for information on upcoming CALTCP training at SCE's Energy Education Centers.

Customized Solutions incentives are available for the installation of dimmable ballasts. The Incentives Application process can be expedited by using the Online Application Tool to estimate energy savings. If you are interested in learning more about dimmable ballasts and how to leverage the available SCE incentives, register for the August 16^th webinar. The Technical Support team is also available to help by emailing APSupport-projects@sce.com or by calling 800-736-4777. 

Express Solutions' incentives for T12 as a basecase retrofit expired on June 30, 2012. If you still have customers with T12s, the available Express Solutions option is to retrofit the T12 to T8 reduced wattage interior lamps & ballasts. Because these retrofits have a T8 basecase, they are eligible for incentives. All other eligibility requirements (as described in the Solutions Directory) and program terms & conditions must be met to qualify for incentives.

The eligible solution codes are:

• LT-84012: T8s reduced wattage interior lamps & ballasts from 32 to 28Watts
• LT-67100: T8s reduced wattage interior lamps & ballasts from 32 to 25 Watts 

This is not an exception to the T12 as a basecase June 30 incentives expiration. The available Express Solutions option uses T8 basecase, thus are eligible for incentives.