LED Parking Lot Lighting
Parking Lot Lighting: LED vs. HPS
Outdoor parking lot lighting employing LED technology.
Item ID: 417
Technical Advisory Group: 2012 LED Lighting TAG (#5)
Average TAG Rating: 3.7 out of 5
TAG Ranking Date: 04/05/2012
TAG Rating Commentary:
- There are a lot of really good products available now. We are at the point where the only challenge is education of the market players, and assuring good system design practices.
Outdoor area and parking lot luminaires employing LED technology are available from a number of manufacturers. The U.S. Department of Energy (USDOE) is encouraging research development and market adoption of the technology, and is providing resources to ensure that objective, ongoing information is available. Replacement of the entire luminaire is most common, although retrofit options for existing housings are beginning to reach the market.
LEDs are well-suited to outdoor lighting applications. In addition to saving energy, LEDs limit light pollution, withstand cold temperatures, are highly durable and produce high-quality light. For these reasons, LEDs are already being deployed in parking lot and outdoor lighting applications. In some circumstances, LEDs in parking lot applications can provide simple paybacks of around three years. It is expected that by 2030, LEDs will reduce energy usage in the outdoor sector by 50%.
LED outdoor area luminaires are available with efficacies over 100 lumens/watt. LEDs are ultimately expected to achieve efficacies over 200 lumens/watt. Energy savings over traditional area lighting systems may be significant – 30% to 75% – depending on the original light levels, technology and controls. In addition, LED luminaires benefit from improved directionality and uniformity, which can allow visibility goals to be achieved at lower peak light levels. LEDs generally do not suffer from frequent on-off cycles or dimming operations. Thus, LEDs are well-suited for applications where the lighting system is under occupancy sensor control, providing increased energy savings in parking lot or other outdoor lighting applications.
Retrofit kits for existing luminaires are also available. Well-designed retrofit kits can deliver the same benefits of integral luminaires.
Baseline Description: Metal Halide area light
Baseline Energy Use: 1989 kWh per year per unit
Baseline calculated using typical wattage for 400W MH, including ballast (454 W) and assuming all night operation (4380 hr/yr).
Manufacturer's Energy Savings Claims:
"Typical" Savings: 50%
Savings Range: From 30% to 75%
Manufacturers typically claim savings of approximately 50%, with higher savings available from integral controls. References from CREEs EDGE High Output Brochure (CREE, 2013).
Best Estimate of Energy Savings:
"Typical" Savings: 46%
Low and High Energy Savings: 38% to 57%
Energy Savings Reliability: 5 - Comprehensive Analysis
Demonstration studies have shown energy savings for LED parking lot lighting of 38% to 57% as compared to standard HID sources. LEDs are now widely available and used for street lighting, area lighting, parking garage lighting, and parking lot lighting.
As of 2010, outdoor stationary lighting used 116 terawatt-hours/year of electricity in the U.S., representing approximately 16.7% of all lighting energy consumption. This percentage of energy use by outdoor stationary lighting will likely apply to the Northwest as well.
The USDOE indicates that LEDs have “tremendous potential” for outdoor lighting applications, and LEDs are expected to achieve 87% of outdoor lighting sales by 2030. Overall reductions in baseline energy consumption in the outdoor lighting sector are estimated to be 46%. Between 2010 and 2030, LEDs for outdoor stationary lighting are projected to save 670 terawatt-hours of electricity nationally.
Energy Use of Emerging Technology:
1,074.1 kWh per unit per year
Energy Use of an Emerging Technology is based upon the following algorithm.
Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
The May 2011 GATEWAY study at Walmart showed LED replacement for a 400 W MH at 211 W. (PNNL, 2012)
Potential number of units replaced by this technology:
Technical potential estimates are based on Navigant's 2011 report for U.S. DOE SSL Program, "Energy Savings Estimates of Light Emitting Diodes in Niche Lighting Applications" http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/nichefinalreport_january2011.pdf
Navigant indicates a total of 14,300,000 HPS and MH parking lot lights nationwide (Table 3.6). Assuming that number of lights is proportional to population, the estimate of potential LED versus MH or HPS parking lot replacement lights in the Northwest is 0.04 x 14,300,000 = 572,000. Garage lighting generally uses much lower wattages. Navigant additionally identifies a total of 66,200,000 mercury vapor, HSP, and MH area and flood lights (Table 3.10). Again assuming that 4% of these lights are in use and potentially replaceable in the Northwest, an additional 2,648,000 lamps are available for a total of 3,220,000 lamps.
Regional Technical Potential:
2.95 TWh per year
Regional Technical Potential of an Emerging Technology is calculated as follows:
Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)
Installed first cost per: unit
Emerging Technology Unit Cost (Equipment Only): $1000.00
Emerging Technology Installation Cost (Labor, Disposal, Etc.): $50.00
Baseline Technology Unit Cost (Equipment Only): $685.00
The May 2011 GATEWAY study (PNNL, 2012) at Walmart showed pricing for LED parking lot luminaires at approximately $1,000, compared to approximately $685 for the incumbent pulse-start MH luminaires. Costs for LED lighting continue to drop and product performance continues to improve.
Installation cost is the author's estimate of approximately 0.5 hr @ $70/hr plus bucket truck and disposal.
Retrofit kits can be lower cost than integral luminaires, but not always as the price of integral luminaires continues to decline. In addition, depending on the design of the retrofit kit, the labor hours required to gut an existing housing and install a retrofit kit may be greater than the labor hours required to simple replace the entire luminaire.
Simple payback, new construction (years): 3.8
Simple payback, retrofit (years): 12.8
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
A variety of case studies have been performed to assess the payback periods for LED deployments in parking lots and outside area lighting. The literature clearly shows that the cost effectiveness of the LEDs varies greatly based on a variety of factors, including the electricity rate, maintenance savings, and whether the LEDs are incorporated into new construction, are replacing luminaires at the end of their service life, or are replacing luminaires with remaining service life. In addition, with the availability, quality, and price of LEDs improving so rapidly, an economic analysis should be done at the time of installation; it will likely be better than economic results reported here or elsewhere.
This technology includes lighting systems for outdoor parking facilities and other area- and flood-lighting applications (but does not include indoor parking garages or wall packs used for architectural lighting). These lighting systems are used to draw attention to businesses and other spaces, to provide a sense of security, and to help traffic move safely through the space.
Today, the most efficient commercially available LED luminaires achieve higher than 100 lumens per watt (LM/W) efficacies. This high efficacy, combined with very long lifespans and low maintenance costs, already make LEDs cost-competitive in many applications. It is anticipated that LEDs will achieve upwards of 200 LM/W, but it should be noted that a straight LM/W comparison does not fully capture the advantages offered by LEDs. Many advocate that white-light sources such as LEDs, which provide broad spectral light distribution, provide greater aesthetic value to an area and a perception of greater security because colors and images are more clearly visible. In addition, at the low light levels typical of outdoor area lighting, white light sources can achieve the same level of visual performance with lower light levels than sources such as high-pressure sodium (HPS) or low-pressure sodium (LPS) that have more of a yellow light color.
The directionality of LED sources also makes them well-suited to applications where down-lighting is desired without excess light being emitted in undesired directions. This attribute is sought after in many outdoor and parking lot applications, in particular when sky glow (light pollution), light trespass, or glare is a concern. In a typical fixture with traditional light sources, 40% to 60% of produced light is lost, meaning that only about half of the light reaches the intended surface. For an LED fixture, losses are only 10% to 20%, meaning that 80% to 90% of the light reaches the intended surface. This means that an overall reduction in light output can achieve the same result as a conventional lighting system.
LEDs generally start up instantaneously and are not subject to the lifetime degradation penalties of fluorescents in applications with frequent on-off cycles. These characteristics combine to ensure that LEDs are well-suited to parking lot or area/security lighting applications, where lighting levels are under automated control with bi-level or multilevel lighting. These controls can include timers, motion sensors, photosensors, curfew dimming, and step switching, all of which may provide further energy savings, particularly in parking lots or outdoor areas with variable traffic levels.
LEDs seldom burn out or fail catastrophically, but rather fade gradually over time. This holds particular promise for parking lot or other outdoor applications because only minimal maintenance is needed. Maintenance can be scheduled rather than dispatched in response to catastrophic light failures that would normally result in blacked-out sections of a parking lot. Emergency maintenance is expensive, so the ability to plan maintenance activities can greatly reduce costs. LEDs are also easily dimmable, and are quite unique in that dimming the lamp generally increases – rather than decreases – the efficiency of the device.
Retrofit kits for existing luminaires are also available. Well-designed retrofit kits can deliver the same benefits of integral luminaires. Retrofit kits typically include a complete LED lighting system, including LED modules and/or arrays, optics, driver, and mounting hardware. Retrofit kits can be lower cost than integral luminaires, but not always as the price of integral luminaires continues to decline. Retrofit kits allow reuse of existing housings, which can be of particular benefit for some applications, such as decorative applications. On the other hand, lumen maintenance, thermal management, light distribution, and physical mounting can be of concern for retrofit kits, as the design must allow for proper operation in a wide variety of housings. For reliable performance, utilize retrofit kits certified for compatibility with the specific make and model of the existing street lights.
As of 2010, the outdoor lighting sector (including parking lot and area lighting applications), is almost entirely captured by high-intensity discharge (HID) luminaires, including mercury vapor, metal halide, high-pressure sodium, and low-pressure sodium lamps. Of the total, 86% of typical lamp operating hours for outdoor applications are currently provided by HID lamps.
LED technology has been in development for over 60 years. The technology was developed alongside the discovery of the first semiconductor p-n junction in 1940 at Bell Labs, and concurrent with the creation of bipolar transistors and the demonstration of efficient light generation from certain alloys in the 1950s and 1960s. While it was clear from an early stage that LEDs held the potential to provide light at very high efficacies, early LEDs had low LM/W outputs and were only suitable for use as signaling and indicator lights.
During the 1990s, LEDs reached a level of efficiency that made them appropriate for high-power lighting application. By 2000, a “new era” of solid-state lighting was emerging. As LED technology became more refined, manufacturers quickly recognized that this technology was a promising solution for parking lot or other stationary outdoor lighting applications. And indeed, this was the first sector for which LEDs would become cost competitive. LEDs can leverage their directionality, dimmability, low maintenance costs, and long service life to effectively compete with more traditional parking lot lighting solutions. LEDs have been deployed in multiple pilot projects, and have begun to be deployed at commercial scale by companies such as at Walmart stores.
The USDOE LED Lighting Facts1 program provides verified performance data and the Design Lights Consortium2 provides a Qualified Products List many utilities use for incentive programs. As of June 2013, the DOE LED Lighting Facts program listed 1,045 LED roadway and area lighting luminaires, and the Design Lights Consortium listed over 8,000 LED roadway and area luminaires on its Qualified Products List.
LED luminaires promise long life and robust design. In contrast with the sudden, catastrophic failure of traditional technologies, LED lamps gradually produce less light as they get older so they do not need to be replaced immediately, which can reduce maintenance costs.
When used in parking lot applications, where the lamp typically operates an average of 12 hours per day, the long life of these lamps results in equipment and labor savings gained from less frequent lamp replacement.
Environmental benefits include no mercury content so disposal issues and costs are reduced compared to most of the competing technologies.
LED “white” light is available in a range of color temperatures. Light distribution is more even than that of most other technologies, sometimes allowing lower light levels per fixture or greater spacing between fixtures while still providing better visibility than traditional sources. LED sources are inherently controllable and do not experience life degradation with frequent switching.
Case studies indicate that pedestrian safety increases with the use of these lights in combination with bi-level controls that respond to occupancy sensors. This alerts drivers that pedestrians may be in the area.
End User Drawbacks:
The primary barrier to consumer acceptance of LEDs is the higher up-front costs of the technology. A case study performed in 2009 found that LEDs were approximately 3.5 times as expensive as MH lamps for a parking lot application, although costs have declined since then and continue to drop rapidly. Customers may also hesitate to adopt a technology whose benefits are largely predicated on a long operating life that has not yet been demonstrated in the real world at large-scale, long-term deployments. This concern is fueled by experiences with failure of lamp drivers, which seem to lack the LED lamps’ longevity and are essential for the fixture’s operation.
Operations and Maintenance Costs:
Baseline Cost: $74.00
per: unit per year
Emerging Technology Cost: $20.00
per: unit per year
Due to the robust nature of the technology, LEDs are expected to have significantly reduced regular maintenance costs as compared to incumbent HID sources. LED sources are expected to operate 50,000 hours and more, unlike HID sources that typically require lamp replacement at about 20,000 to 34,000 hours. However, LED drivers may fail before the end of useful life of the LED source, and these will require replacement.
At this time, there are no additional costs for disposal of LED products at end of life. Manufacturers have expressed some interest in making them recyclable.
Estimated costs are from a 2011 DOE Gateway study at Walmart. (PNNL, 2012)
Anticipated Lifespan of Emerging Technology: 15 years
Performance specifications available from the USDOE state that LED luminaires produced in 2012 for use in outdoor applications are expected to achieve a 58,800 hour lifespan. Given an assumed operating cycle of 11 hours per day, this translates to approximately 14.6 years of daily operation.
The effective life of well-designed retrofit kits is expected to be equivalent to that of new luminaires, however can be impacted by the housing in which the retrofit kit is installed. The DLC specifies a minimum required lumen maintenance for retrofit kits that is equal to the minimum required lumen maintenance for new luminaires. This lumen maintenance must be demonstrated in a representative housing.
Primary competition in this market is from HID lighting, primarily MH and HPS lamps. Approximately 86% of the current outdoor stationary lighting systems are of the HID type.
Reference and Citations:
LED Lighting Facts
U.S. Department of Energy
Considerations for Successful LED Applications
Lighting Research Center
2010 US Lighting Market Characterization
Navigant Consulting, Inc.
Energy Savings Potential of Solid-State Lighting in General Illumination Applications
Navigant Consulting, Inc.
Energy Savings Estimates of Light Emitting Diodes in Niche Lighting Applications
U.S. Department of Energy, Building Technologies Program
Lighting the Future: Walmart Converting Hundreds of Stores’ Lot Lighting to LEDs
Jo-Ann Installs Largest LED Parking Lot Lighting System in the Nation
Retail Facility Business
Application Assessment of Bi-Level LED Parking Lot Lighting
Pacific Gas & Electric Company
Demonstration Assessment of Light-Emitting Diode (LED) Parking Lot Lighting
Pacific Northwest National Laboratory
Demonstration Assessment of Light-Emitting Diode (LED) Parking Lot Lighting, Phase I
Pacific Northwest National Laboratory
Exterior Lighting for Energy Savings, Security and Safety
Pacific Northwest National Laboratory
History, Development, and Applications of High-Brightness Visible Light-Emitting Diodes
Journal of Lightwave Technology
Parking Lot Luminaire Calculator
Lighting Research Center
Outdoor Lighting: A Short Guide to Applications, Objectives and Considerations
Assist recommends... (Alliance for Solid-State Illumination Systems and Technologies)
Recommendations for Evaluating Parking Lot Luminaires
ASSIST recommends... (Alliance for Solid-State Illumination and Technologies)
LED Outdoor Area Lighting Fact Sheet
Energy Efficiency & Renewable Energy
DesignLights Consortium Qualified Products List
DesignLights Consortium, Northeast Energy Efficiency Partnerships, Inc.
CREE Edge High Output Brochure