Energy

San Diego Streetlights

To replace all of the nearly 40,000 streetlights with broad spectrum lighting to increase energy efficiency and save money.

Topic Areas Addressed:

Energy

Keywords:

lighting, San Diego, streetlights, street lamps, induction lamps, broad spectrum

Submitting Jurisdiction:

City of San Diego

The City of San Diego is looking to provide a more energy and cost efficient solution to current street lamps. It is proposed to use induction lamps in place of traditional high-sodium pressure lamps. This change of 40,000 lamps would result in great energy, maintenance, and economical savings.

Public Outreach and Education:

Approximately 25 broad spectrum “white light” streetlamps were installed along the street. A public survey was conducted to determine if there is any significant difference between broad spectrum lights and high-pressure sodium (HPS) lamps.

Target Audience:

City Officials

Measurable Outcomes:

Preliminary results indicate no significant physical difference between HPS streetlamps and broad spectrum streetlamps. Additionally, life cycle assessments were completed for both light-emitting diode (LED) and induction lighting. Current data demonstrates that induction lighting is less expensive than LED lighting for initial cost and maintenance.

Public Support & Opposition:

An extensive public outreach effort was undertaken to get input and feedback on how broad spectrum lighting affects the community at large. Volunteers from around the community were recruited and asked to evaluate how different types of light affected the community (better/worse visibility, more consistent light, better color clarity, etc) and how they felt about it (more/less safe, like or dislike, etc). After extensive review and assistance from a well-known University, it was determined that overall, broad spectrum lighting represented no significant change in lighting quality or safety compared to traditional street lighting (HPS, LPS). The pilot project also received extensive support from the City’s elected officials.

Issues/Barriers:

Due to San Diego being home to two major research telescopes, the Dark Skies Association (DSA) expressed concern that broad spectrum lighting would cause detriment to the night sky. The City along with other regional municipalities and the local utility convened a region wide “street lighting” working group (SLWG) that worked to address concerns raised by the DSA. The SLWG listened to presentations from astronomers and other professionals to get a better understanding of how broad spectrum lighting could impact the night sky and its potential detrimental effects on circadian rhythm cycles.

The SLWG found it difficult to agree on one type of lighting (LED or Induction) so the group found it necessary to develop two different specifications. In developing these specifications, it was difficult to find agreement on how to balance energy efficiency goals with environmental impacts. The DSA recommended a color temperature of 3,000 Kelvin to reduce night sky impact; however, this reduces the energy efficiency of the lamp. This issue continues to be debated, with larger entities like the U.S. Department of Energy weighing in on the issue.

Fiscal Impacts:

Current data indicates that induction lighting is far less expensive and far more energy efficient than HPS lamps. The City estimates that the payback for each lamp replaced with an induction luminary is between 6.5 to 9 years. It is estimated that replacing 40,000 fixtures will result in a savings of 20 million kilowatt-hours and $2,400,000 in energy savings annually, and $2,000,000 savings in maintenance over the life of the fixture.

Because the upfront costs of the luminaries are much higher than the incumbent HPS fixtures ($500-750 each including labor compared to ~$200) the cost of replacing the 40,000 existing streetlights will be significant. In order to fund this endeavor, the City is working with state and federal agencies, such as the California Energy Commission and the U.S. Department of Energy, to secure grants and low interest loan to help cover the cost of the retrofits.

Additionally, because the SLWG was able to develop region wide standards for both induction and LED luminary retrofits, the City also hopes to work with other municipalities to leverage collective buying power and negotiate lower costs for each fixture.

Legal Issues:

None identified.

Originating Source:

The San Diego Streetlights Project builds on experience and lessons learned from previous streetlight conversion studies in Alaska, Michigan, and Northern California.