Topics from the Power Line: Targeting outdoor display lighting to reduce energy use

Editor's note: The Energy Services Bulletin features real answers to real questions posed to our staff at the Energy Services Power Line. We hope you find it useful.

Question:

How much energy is consumed by outdoor display lighting in Washington state?  Are any state or utility programs targeting this end-use for peak demand reduction? 

Answer:

One of the challenges in obtaining such data is that people who know the most about outdoor lighting—planners and designers—aren't usually focused on macro energy use. A second challenge is that most information sources don't differentiate non-essential outdoor display lighting from the category of outdoor lighting that includes street, security and public safety lighting such as parking lots.

Curtailment: few pros, many cons

Debra Tachibana with the Evaluation Unit of the Energy Management Services Division at Seattle City Light noted that outside lighting represents about 36 average megawatts of the utility's load. That amounts to 3 to 4 percent of the utility's total connected load for lighting buildings, sidewalks, parking lots/garages, roadways, work-yards, architecture/landscape and signage.  A fraction of 1 percent of this load would be for display lighting, and there would likely be resistance from retailers whose livelihood depends on exposure.  The great majority of this lighting is for security and public safety; so, for liability reasons, building owners would likely resist attempts to curtail this load.

The unit manager concluded that, "Curtailment of outdoor lighting would be extremely challenging. Due to concerns with safety and security, the level of compliance would be very low while economic liability could be quite high."

Also, there is a surprising amount of effort involved in reducing this type of municipal energy use. For example, to shut off every other streetlight, as Tacoma tried once, requires someone to actually climb up each lighting fixture, turn it off and post a sign on it informing the public that it's off on purpose and not broken. 

More state measures

The following are examples of efforts in other states to pursue outdoor lighting curtailments:

1. California Governor Gray Davis signed the Reduction of Outdoor Lighting Act in as a measure to address the state's energy crisis in 2001. Outdoor Lighting Zones are also covered in the 2005 Building Efficiency Standards.
   

2. During that time, the California Independent System Operator (Cal-ISO) called upon citizens to reduce power demand to avoid a stage-two power emergency. They did not specifically address display lighting.
   

3. The International Dark-Sky Association has a number of references and links to municipalities that have instituted restrictions on lighting, but these focus on reducing light pollution and improving energy efficiency rather than on peak demand reduction.
   

4. Utility Options is a database of actual programs operated by utilities. You can search the database for lighting programs.

Although your question specifically targeted outdoor display lighting, you may want to consider other measures that are easier to implement and enforce, and have more impact and less potential political fallout.

On a related note, the California Energy Commission asked Jim Benya, a well-known lighting designer, to come up with recommendations to reduce power shortages, his first thought was to recommend occupancy sensors and photosensors in offices. However, further analysis determined that at the time there weren't enough available licensed electrical contractors in the state to install them. He therefore altered his recommendation to encourage the use of CFL task-lighting and desk-top occupancy sensors to turn off the task-lighting and computer monitor when occupants were away from their desks for a pre-determined length of time. For offices with windows, the circuit powering overhead lighting would be turned off.  These measures avoid the lack-of-availability problem and expense of hiring electrical contractors.

Resources

Reduction of Outdoor Lighting Act

Outdoor Lighting Zones

California Independent System Operator

International Dark-Sky Association

Utility Options Database

California Energy Commission

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