Two factors have an impact to sky glow or light pollution, which are up-light and the lumen output (light level) of the fixture.
To address the up light, the majority of the new LEDs are “cobra-head” fixtures and they have received the best ranking – a “zero” – when it comes to the amount of up-light they produce. FortisAlberta’s fixtures are “Dark Sky” friendly with zero up-light, which means less light pollution and/or sky glow as the light is directed downward.
To address the lumen output, LEDs typically require approximately 47-58 per cent of the lumen output of the HPS light to achieve the same light levels on the pavement. This is due to the efficiency of the light source being able to direct the light where it needs to be versus the HPS light having a lot of wasted light and lack of control.
By eliminating the up light and reducing the lumen output of the light source, the LED significantly reduces light pollution.
Show All Answers
FortisAlberta owns and operates more than 100,000 streetlights in Alberta.
The streetlight industry has developed LED technology to support dark sky and energy efficiency goals. FortisAlberta strives to meet the needs of its customers and in response to customer requests, the conversion option was introduced. The company is committed to improving the energy efficiency of its infrastructure, while controlling costs for our customers.
In response to customer requests and to improve the energy efficiency of our infrastructure, effective Jan. 1, 2016, FortisAlberta changed its standard for streetlights to Light Emitting Diode (LED) technology for all new construction and developed a conversion option for customers who wish to convert their existing streetlights from HPS (High Pressure Sodium) to LED fixtures.
Effective March 1, 2017, any new requests for HPS lighting will only be available under a non-standard lighting agreement. Municipalities accepting new installations of non-standard lamps, luminaries, and/or poles will be responsible for the purchase and stocking of replacement materials for non-standard lamps, luminaries and/or poles.
LED technology provides:
• more even and efficient distribution of light which is controlled and focused downward reducing light trespass and sky glow
• reduced energy consumption resulting in energy savings and reduced greenhouse gas emissions; and
• reduced outages and longer light life spans resulting in reduced maintenance costs.
More than 90 percent of Municipalities within FortisAlberta’s service territory have signed up for the LED Streetlight Conversion Option. In total, approximately 80,000 fixtures will be converted to LED technology under this Option. The LED Streetlight Conversion Option covers all Rate 31 cobra head style fixtures. Non-cobra head style fixtures or decorative fixtures and yard lights will not be converted at this time.
Municipalities around the world are switching to LED lights to save both money and energy. LED lights have approximately 50 per cent lower energy consumption compared to their HPS luminaire predecessors. HPS lights, most installed in the mid-1980s, are at the end of their useful lives and need replacement. LEDs will provide better service reliability and lower maintenance costs. The new LEDs have a longer lifespan - about four times that of the bulbs we currently use. This translates into ongoing savings in maintenance costs as result of the extended maintenance cycle for bulb replacement. Less maintenance also means fewer service vehicle trips for repairs and as a result, reduced carbon emissions.
LED street lighting is visually different than lighting from conventional fixtures. HPS streetlights produce a light color that is yellowish or orange hue. LED streetlights are more focused than HPS streetlights to ensure that more of the fixture’s light shines onto the street and sidewalks and less light spills into adjacent areas. LED streetlights and comparable HPS streetlights produce the same intensity of light; however, some people may perceive that the LED streetlights that FortisAlberta is installing are brighter because they are whiter than conventional HPS streetlights.
LED fixtures generally produce less light pollution than other lights because their light is more directional and focused; LED lighting also increases contrast and improves color rendition and depth perception. FortisAlberta uses cobra-head LED fixtures that comply with International Dark-Sky Association (IDA) standards for shielding, which minimizes glare and light spillage.
In its simplest terms, a Light-Emitting Diode (LED) is an electronic component that emits light when an electric current is passed through it. The colour of the LED is obtained by adding a phosphorous material over the LED chip. LED streetlights are extremely energy efficient, do not produce any UV rays or infrared radiation, can be easily controlled, and have long life spans of more than 20 years. LED lighting provides an exceptional colour rendering index (CRI) of 70 or better.
HPS (High Pressure Sodium) is a high intensity discharge lamp with an arc tube containing Sodium and Mercury, which when vaporized produces light. The Sodium radiation dominates the colour appearance of the light, which is characteristically a golden or yellow colour temperature of 2,100K. HPS streetlights have a poor colour rendering index between 20-21 when compared to LED and other types of lighting.
Color Rendering Index (CRI), is a scale from 0 to 100 per cent indicating how accurate a given light source is able to reveal colours when compared to a reference or natural light sources. Generally speaking, the higher the numeric value or CRI is, the better the light source is at accurately rendering or displaying the color of an object.
The term BUG relates to the following: Backlight, Uplight, and Glare ratings, which are used to evaluate the luminaires optical performance related to light trespass, sky glow, and high angle brightness control.
The rating for the zone is assigned a numeric value between zero and five. The lower the number, for example U0, the better the luminaire performs in these criteria. In this example, a value of zero for uplight means that zero light is emitted into the atmosphere.
In Dec. 2016, new LED colour temperature products were made available by the approved streetlight manufactures and FortisAlberta’s assessment of the new products determined that the efficacy, environmental efficiency and price were comparable to the existing 4,000K standard. As a result, FortisAlberta has updated its standard from 4,000K to 3,000K. FortisAlberta is acting prudently to ensure it stays in-line with industry trends and consumer preferences while operating in the best interests of its customers.
No they will not. A colour temperature of 3,000K is slightly whiter than a typical incandescent bulb used in your home. The 3,000K LED lights also have much higher colour rendering (70) than HPS lights (20-21).
Colour temperature or Correlated Colour Temperature (CCT), expressed in degrees of Kelvin, is commonly used as a measure of lighted appearance. The higher the colour temperature, for example 5,000K, the whiter to whitish blue the light appears. The lower the colour temperature, such as 2,100K, the warmer or yellower the light appears. While the light output can be the same, the higher the colour temperature, the brighter the light appears, while warmer colour temperatures seem less bright.
Yes, the potential impacts were evaluated. The LED technology FortisAlberta is installing will use a warmer light, which means that exposure to blue light will be minimal. Additionally, the U.S. Department of Energy released a publication in 2013 and concluded that LED products are no more hazardous than other lighting technologies.
There is no evidence that LED streetlights impact human sleep cycles any differently than HPS streetlights that have been used for the past 30 years. When considering the effects of light at night, indoor lighting is more of a concern. The quantity of light emitted by streetlights is many times lower than that emitted by typical indoor lighting, TVs, tablets or PC screens. The U.S. Department of Energy has published a number of documents to address the statements made by the American Medical Association (AMA) with regards to the stated health issues.