I wrote this article for the March issue of tED Magazine. Reprinted with permission.
The U.S. Department of Energy’s (DOE) 2010 Lighting Market Characterization estimated some 180 million lamps were in service in outdoor stationary lighting installations. More than half of these were HID lamps, predominantly high-pressure sodium and metal halide. Some 19 million LED lamps had been installed, or 10.8 percent of the total.
In 2014, DOE’s Municipal Solid-State Street Lighting Consortium published the results of a public street and area lighting inventory survey conducted among utilities and governments. Sixty-two percent said they were using LEDs, with 8 percent naming it as the most prominent technology in their system and 30 percent as the second-most prominent. Eighty-two percent said high-pressure sodium remains the most prominent technology.
This research points indicates both a rapidly growing acceptance of LED lighting in outdoor area lighting applications and a large retrofit market. The primary demand drivers are energy efficiency, long service life and control flexibility.
“The outdoor area lighting market will experience a continued push for reduction of energy usage and lower site power density, requirements to be mandated by legislation and/or green initiatives,” says Debbie Bell, Product Manager, Kim Lighting. “Current project designs demonstrate a greater adoption of LED technology as the lighting performance continues to improve in higher lumen packages. Future trends indicate the welcome return of the lighting designer in the selection process for outdoor lighting, moving away from the ‘if it glows, it goes’ LED luminaire purchases.”
“LED luminaires are now typically the preferred choice for all general lighting applications, particularly outdoor lighting,” says Tom Hinds, Manager of Outdoor Product Management, Cree Lighting. “Roadway and street lighting are some of the most popular outdoor lighting applications for LED luminaires, especially since it can account for up to 40 percent of a city’s electric bill, whereas area LED luminaires are often found in area and floodlight applications such as campuses, office and retail complexes, medical centers and municipalities.”
“Based off industry data, LED now comprises more market share revenue than all other light sources combined,” adds Eric Snyder, Marketing Manager, Eaton’s Cooper Lighting business. “This is certainly skewed with a mixture of renovation projects as well as new construction, but it’s still safe to say that LED now comprises more market revenue than any other light source for area lighting applications.”
Aflac, headquartered in Columbus, Georgia, insures more than 50 million people worldwide. The company decided to retrofit its support center parking lot located at its headquarters with LED lighting. Sixty-one 1000W metal halide luminaires (“before,” above image) were replaced with fifty-three 303W LED luminaires (“after,” below image), resulting in 76 percent energy savings and a 3.4-year payback. Images courtesy of Cooper Lighting.
LED area lighting luminaires are available from numerous manufacturers with products able to replace 100W up to 1000W HID luminaires. Compared to HID, a greater offering of solutions is available, with a wide range of choices of optical distributions, color temperatures and color rendering. Improved optics in specification-grade products result in a more uniform and consistent light level than HID sources, which emit as much as 30 percent of their total lumen output straight down (at nadir), while providing control allowing light to be placed more precisely.
The latter capability allows the design of products for specific applications. For example, several major manufacturers offer an optical distribution designed specifically for front row lighting in auto dealerships. In that application, the mounting height is typically lower but typically pose higher light level requirements. Specification-grade LED luminaires offering adaptive optics are well suited to retrofit applications where pole mounting locations are fixed and the LED luminaire must produce output specific to site geometries.
As source efficacy improves, manufacturers are able to produce more light from fewer LEDs, resulting in luminaires trending away from older clunkier models and more toward slimmer, light-weight designs. This potentially reduces pole diameter and cost in projects where new poles are installed.
In an HID system, the lamp is typically replaced more frequently than the robust magnetic ballast. In an LED outdoor luminaire, the driver is likely to fail before the long-life source. As a result, many LED luminaire designs feature access to electronic components using quick disconnects, toolless entry and separate gear and optical chambers. The luminaire should feature surge protection to protect the electronics.
Being instant-ON, with minimal penalty for frequent switching, and with dimming available standard or as a standard option, LED is also significantly friendlier with lighting controls. This is an important consideration as commercial building energy codes increasingly mandate bilevel lighting control for outdoor area and security lighting. LED area lighting luminaires are available with many integral occupancy and photosensor solutions, including wireless controls that simplify installation.
Manufacturers estimate energy cost savings of 50-75 percent, which can be increased to 80 percent through the use of controls. “In a one-for-one comparison, greater than 50 percent energy reduction is common,” says Snyder. “In a new construction scenario, there is more liberty to adjust the pole height, fixture lumen package, fixture count, etc. This level of flexibility when combined with controls can exceed a 75 percent reduction relative to HID.”
Los Angeles Mayor Villaraigosa recently announced the completion of the four-year program to retrofit 141,089 street lights in Los Angeles with LED lighting—reducing the city’s energy use by more than two-thirds. Image courtesy of Cree Lighting.
In the retrofit market, rebates offered by utilities and energy efficiency organizations can reduce initial cost while presenting baseline performance criteria tracked to current technology. In retrofits, Snyder says the most cost-effective option is to remove the existing HID luminaire and replace it with an LED luminaire. “With this approach, the new LED luminaire is factory-built with a warranty and is typically less labor-intensive and safer than trying to integrate a generic retrofit module into an existing luminaire,” he says.
Bell cautions that despite advances in education and standards, the vast array of options coupled with incomplete standards indicate it’s still a buyer-beware time in LED lighting. “LED lighting remains the Wild West for end customers who are looking for a common denominator when evaluating the variety of LED products,” she says. “So many options and so few standards to dictate conformity and sustainable design can result in an unsatisfactory experience with LED luminaires, which in turn could damage the credibility of the electrical distributor. When evaluating an LED system, the lowest cost can reflect the lowest value.”
As a result, the best way to navigate the new world of LED lighting may be to ally with manufacturers that distributors trust, become educated about outdoor lighting and the many control options available, and qualify products that both save energy and provide good performance that will satisfy customers. Good sources of product information include the DesignLights Consortium’s Qualified Products List (www.designlights.org), Lighting Facts (www.lightingfacts.com) and the Next Generation Luminaires Design Competition (www.ngldc.org).
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