The Dark Side of LEDs

Image: Audio Luci Store
Image: Audio Luci Store

LEDs’ benefits outweigh the potential problems. That doesn’t mean, however, that challenges don’t exist.

At this point, the issues are most obvious in street light deployments. At its website, Chicago radio station WEBZ yesterday reported that 270,000 streetlights will be replaced with the LEDs during the next four years. There are issues, according to the piece, related to the brightness of the lights and whether or not shielding is necessary to limit the light to where it is intended. The potential problems are serious:

A growing body of research links blue light exposure at night to sleep disruption and health problems. This research led the American Medical Association to issue a report this summer on LED streetlights, warning of potential problems with glare and damage to human health and the environment. It further recommended that cities choose lights with shields and a color temperature of 3000 Kelvins or less. Chicago’s proposal, so far, complies with the latter.

The LEDs seem to be becoming something of a political football. While the city is complying with the 3,000 Kelvins limit, it maintains that the shields are unnecessary.

A comprehensive look at the problems associated with LEDs was posted this fall by The Washington Post. The report featured a study by the American Media Association. That study, which is linked to from The Washington Post piece, says that the association supports LEDs, but advocates use of the least amount of blue light possible. The AMA says that 3,000 Kelvin should be the maximum used for outdoor installation and that the LEDs should be shielded and dimmed during off-peak hours.

The potential problems are wide ranging. The Washington Post story points to disruption of sleep patterns, increased risk of cancer and cardiovascular disease and “light pollution” that is complained about by the astronomical community.

Phoenix is another city with LED issues. AZ Central earlier this month reported that the city has agreed to a bit of a do-over. Phoenix has been installing LEDs for the past four years. However, on November 30, the city council approved a contract with Ameresco on replacing the LEDs with those that emit yellow or amber light rather than the white or blueish that have been used to date.

The story says that the original LEDs had an intensity of 4,000 Kelvin. The replacements are 2,700 Kelvin. The overall savings by 2030 is expected to be $52 million, with a net savings of $22 million when installation costs are factored in, the story says.

The small city of Clarkson, GA, is having an LED problem of a different sort. Georgia Power has replaced existing streetlights with LEDs. However, it is not passing on any of the savings to the city. The mayor, according to a report this week at WTVM, thinks that there is some “wiggle room” and some of savings should be given to Clarkson.

Municipal energy managers must, of course, pay careful attention to all the issues regarding LEDs and streetlights. It’s complicated because there are multiple issues. The good news is that corrective actions – a lower Kelvin limit and less intrusive colors – are likely to handle the problems. The important thing, of course, is to pay attention to the issue before deployment. Doing that, it seems, would have saved Phoenix a good deal of money and aggregation.

The other element to note is more cautionary. No matter how cut and dried a new technology seems, careful planning and exploration are necessary before deployment. It doesn’t seem that the precise issues that affect street light LEDs would impact those used within facilities. That is not certain, however, and health concerns should be explored. There also may be issues that are unique to indoor environments.

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2 thoughts on “The Dark Side of LEDs

  1. Observed issue: Icicle Formation. More efficient LED = less wasted heat = cooler fixtures. Icicles no form on street and parking lot lights. At 40 ft, icicles will reach 20 mph +/- before hitting the ground – high risk to people and property.

  2. Kelvin is color temperature, not intensity, as indicated by this article. The lower the color temperature, the warmer the color of light.

    Intensity is measure in lumens. Overlighting areas is another problem area, since the appealing energy savings of LEDs make it tempting to make streets brighter while simultaneously saving money. That results in unhappy residents and birds that chirp all night.

    Be smart, use warm white lights, shield fixtures so the lights don’t shine in people’s windows, and don’t overlight an area.

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