Street Lights And Stargazers

by The Editors on May 18, 2009


The City of Carlsbadistan’s plans to replace 7,000 old high pressure sodium streetlights with new high-efficiency induction light may cut the City’s greehouse gas emissions from City ops by 20 percent, but according to a Michael Burge story in the San Diego Union-Tribune they could interfere with the stargazers at the Palomar Observatory.

“I don’t know what the new lighting fixtures will look like or how bright they are, but white lights are not friendly to research astronomers for a variety of reasons,” said Scott Kardel, public affairs coordinator for the observatory. . . Kardel said if the new streetlights aren’t too bright and don’t direct their beams skyward, they may not be as troublesome as the older streetlights. . . “Hopefully, they’ll be fully shielded,” Kardel added, saying he’ll look at some of the lights before Tuesday’s meeting.

More importantly, we’re hoping they won’t be shining in our windows and keeping us up all night. Follow the jump for the complete press release from the City.

[Link: San Diego Union-Tribune]New Streetlights Save Money, Help Environment

CARLSBAD, Calif. – At its May 19 meeting, the Carlsbad City Council will consider a project to replace more than 7,000 high-pressure sodium streetlights throughout Carlsbad with high-efficiency induction lights. The project will save nearly $400,000 a year in energy and maintenance costs and reduce greenhouse gas emissions from city operations by 20 percent.

Combined with the recently approved hydroelectric power project, the street light project will allow the City of Carlsbad to meet the state’s target of 30 percent reduction in greenhouse gas emissions 10 years ahead of schedule.

City staff notes that the switch to the new lights will reduce the city’s energy consumption for street lighting from 5.1 million kilowatts a year, to just over 2 million kilowatts.

Once the new lights are in place – a process that will take 14 to 16 months – the city will see a reduction of 1,240 tons year of greenhouse gas emissions, the equivalent of taking 170 cars off the road for a year, or planting 124,046 trees.

As part of its sustainability policy, the City of Carlsbad has adopted environmental guiding principles, quantified its carbon footprint, and approved projects to improve the fuel efficiency of its vehicle fleet and install hydroelectric turbines at Maerkle Reservoir.

The changeover to induction lights will cost just over $3 million. About half of the money will come from a combination of federal grants and incentives from San Diego Gas & Electric. The city will apply for a low-interest loan from the California Energy Commission to pay for the rest of the project, and the loan will be repaid through savings in annual maintenance and electricity costs.

City staff has estimated that once the high-pressure sodium lights are replaced with energy efficient induction lights, the city’s annual $600,000 bill for street lighting will be reduced by $290,000. The city expects to save an additional $100,000 per year in maintenance costs, because the new lights have longer warranties.

In addition, induction lamps have an expected life span of 100,000 hours, or 24 years, versus a 25,000 hour lifespan, 6 years, for the current high-pressure sodium lamps.

The last major change to the city’s streetlights occurred 30 years ago, when the city changed from mercury vapor lights to the present high-pressure sodium lights.

Along with a reduction in greenhouse gas emissions, the new induction lights are made with less mercury than the current lights, which will save money on hazardous waste disposal and reduce impacts on the environment.

The new induction lights contain one-tenth of the mercury as the current high-pressure sodium lights, and the mercury is in a solid form, rather than liquid or gas, which makes it easier to recover and recycle than the material used in the current lamps.

The new lamps also offer a public safety benefit. Their illumination appears white rather than the yellow light of the high-pressure sodium lamps. Witnesses and crime victims will be able to more accurately describe colors and other visual details to law enforcement.

The city has installed about 20 induction lights in the downtown village area to test their effectiveness. During its research, city staff also tested LED lights, but determined induction lights have a more established track record, a longer warranty and are less expensive.

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