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Lessons Learned from Solid-State Lighting Pilot Projects

Lessons Learned from Solid-State Lighting Pilot Projects

What the city of Raleigh, N.C., took away from six years of experience with LED installation, implementation, maintenance, and cost analysis

Located in the tech-savvy Research Triangle region of North Carolina, the City of Raleigh (population 420,000) has benefited from many spin-off industries that have emerged at the three flagship research campuses (NC State University, UNC-Chapel Hill, and Duke University). In 2007, technical advances in light-emitting diode (LED) efficiency and a partnership with a local LED startup allowed the city to be at the forefront of an emerging market for solid-state, white-light, general illumination lighting products that had otherwise been barely tested in real-world situations.

Beginning with a pilot project in January 2007 to replace high-pressure sodium light fixtures with LEDs in one level of a municipal parking deck, the city has since completed more than 75 LED lighting projects in dozens of municipal facilities, while carefully tracking performance and efficiency. From streetlights to low-bay, gallery lighting to architectural, interior, and exterior applications, the good news is that manufacturers’ claims for the products the city installed have generally proven true — both for durability and efficiency. There were some excellent surprises and a few disappointments along the way. But after six years of experience, the city continues to invest in LED lighting across the enterprise as prices continue to drop, and efficiency and choice continue to expand.

Solar-powered LED lighting at Marsh Creek Maintenance Yard, Raleigh, N.C.

Why LEDs?

Raleigh has a broad-ranging sustainability program, of which energy efficiency is only one part. In 2011, the U.S. Chamber of Commerce named Raleigh the “Most Sustainable Mid-Sized City” in the United States. Solid-state lighting is an emerging, energy-conserving, non-polluting technology that can result in direct cost savings to citizens. It also represents economic development in the area, considering the fact that a local LED manufacturer added hundreds of high-paid jobs in this market during the 2008 to 2012 recession.

The local economy depends on attracting knowledgeable workers and innovators in emerging fields. A municipal policy to stay at the forefront of innovation and sustainability sends the right message to citizens and companies wishing to locate in the region. High-tech, cost-saving, and energy-efficient programs that generate good-paying jobs make for great local politics, and Raleigh has benefited from strong support for this program by its elected officials. In addition, investment by the federal government in the Energy Efficiency and Conservation Block Grant Program (EECBG) provided resources beginning in 2009 to help leverage a number of projects at little or no cost to local taxpayers.

The technology works

Municipal facilities have proven to be an excellent solid-state lighting testing ground. Not only do local governments use a wide variety of interior and exterior lighting applications, but the benefits LED technology accrue directly to the owners (citizens) and governments can also offset the high initial capital cost of retrofit with a life-cycle costing analysis that accounts for the long-term benefits of energy and maintenance efficiency. In Raleigh’s case, one early surprise was the positive reaction of citizens to the quality of light from new LED installations, coupled with energetic early acceptance (even evangelism) by what one might think would be the least likely of champions — the hard-nosed, bottom-line-oriented facility managers.

Raleigh officials keep records on public feedback for all test projects, but scientific sampling and focus groups were involved in at least two projects early on in the implementation of LED lighting projects. The original pilot in the municipal parking deck (low-bay retrofits of HPS fixtures to LED on one level of the deck) resulted in 75% of users indicating they felt the LED level of the deck was both brighter and safer than other levels, while casting approximately 11% fewer footcandles. Streetlights at both 4,700K and 6,000K color temperatures were tested by a focus group of citizens with an overwhelmingly positive response to LED streetlights in general over traditional street lighting — and a modest preference for the warmer color temperature when compared side-by-side with LEDs at the cooler color temperature.
Surprisingly, what caused the most dramatic reaction with facility managers wasn’t the quality of light or the energy-efficiency of the early projects. It was the implications for maintenance savings promised by this new technology that caught their attention. With an ever-increasing need for facility maintenance staff to have more advanced skills — licensed plumbers, electricians, etc., to handle sophisticated building systems — the promise of being able to free staff up from routine tasks, such as cleaning light fixtures or changing bulbs, quickly adds up to financial savings that approach and sometimes exceed energy savings.

Solar LED parking lot luminaires highlight dramatic color temperature contrast with traditional HPS streetlights.

For example, an analysis done in 2008 for a new underground parking facility showed the savings calculated only from the avoidance of the roughly 14-month cycle of replacement of traditional metal-halide bulbs, coupled with approximately 60% savings in energy demand paid for the difference in initial cost of LED fixtures in about 3.5 years. Low-bay lighting and pole-mounted lighting in city-owned exterior parking and pedestrian areas have proven to be the city’s best investments so far. All new exterior lighting in the city’s 221 park units and in the Municipal Building complex over the past four years has been LED-based, resulting in excellent citizen feedback and substantially lowered maintenance and energy costs. In addition, a recently completed Climate Energy Action Plan completed by the Office of Sustainability showed conversion of the city’s remaining downtown structured parking decks to LED lighting was one of the top 10 strategies enterprise-wide for investment in climate-related projects because of its short payback.

Other LED projects in the city’s inventory include a nearly complete retrofit of the Performing Arts Center, including lobby lighting, show poster lighting, architectural exterior lighting, and exterior pedestrian area lighting. The city has also installed LEDs in the following spaces: on greenway underpasses on its 80-mile system of urban greenways; on a pedestrian bridge spanning a major interstate highway; and in interior applications in community centers, the mayor’s office, elevators, and in the LEED Silver Raleigh Convention Center. Three solar-powered LED lighting projects have been completed. Two major works of art have been constructed in downtown Raleigh with programmable LED lighting displays as major elements of the design, and three major new facilities (a water treatment plant, transit operations facility, and solid waste operating facility) include 100% exterior LED lighting.

One of Raleigh’s concerns early on in the program was the length of usable service for light fixtures. Because LEDs are expected to slowly dim over time — until they reach a replacement point represented by L70 (or 70% of the original luminosity of the LEDs) — manufacturers’ promises about how slowly their products will reach this point were extremely important. After 2.5 years in service, light levels in one of the city’s early installations (544 low-bay fixtures in an underground parking deck) were re-measured by engineers responsible for the original design. This measurement showed the LEDs were dimming at about one-half the rate expected if they were to meet the manufacturer’s projected lifespan. This is good news for the economic analysis used to model savings in the deck and will likely result in the extension of the usable lifetime of these fixtures.

Not without problems

Quality has become a decreasing issue in the industry. In fact, many of the major reputable lighting companies have now embraced LED technology and offer a variety of high quality products. However, this was not true early in the emergence of general illumination LED lighting.

New LED streetlight installed in downtown Raleigh. The city is considering a replacement project that would change 30,000 streetlights to LED.

On several projects, Raleigh learned some interesting lessons, particularly about water. The region is generally blessed with ample rainfall, but moisture is not a friend to any light fixture, particularly a solid-state fixture. Early landscape up-light fixtures (both in urban environments and on a major pedestrian bridge) were a disappointment, primarily because the shrink-swell resulting from a wide temperature range resulted in failed seals. Water was also a factor, for
different reasons, in a failed test of high-bay fixtures in an aquatic center, where the first-generation fixtures were not well designed for the harsh, humid environment of a pool enclosure.

High-bay is a very desirable application for LEDs because of the difficulty and expense of changing bulbs in traditional fixtures. The city operates a number of aquatic centers, gyms, etc., where solid-state high-bay lighting would be cost-effective, but competitive athletic facilities must meet stringent standards for lighting. Very little test data for LEDs is available relative to these standards. Despite these few shortcomings, LED fixtures in a wide variety of interior and exterior city applications have performed exceptionally for several years, with a number of exterior fixtures surviving an EF3 tornado while remaining operational. For those relatively few fixtures that failed for reasons other than water, power supplies (rather than the solid-state componentry) were generally at fault. Manufacturers’ warranties in these cases were solid, with all failed fixtures under warranty replaced quickly at no cost to the city.

Altered landscape since 2007

The first LED fixtures installed by the city generated roughly 40 lumens per watt  (lpw) — a dramatic achievement at that time. Six years hence, it is now common to see 100 delivered lumens per watt routinely in newer fixtures, with 140 lpw or more coming to market and over 200 lpw delivered by LEDs on the test bench. This has resulted in a steady improvement in quality and efficiency as well as a steady decrease in cost for most LED products. The “scariness” of this emerging technology has abated as more and more municipalities make investments in LED lighting with good results. It is also a time when more political skepticism is being expressed about “sustainability” initiatives, and fewer dollars are available for emerging energy-efficiency technologies on the federal level. Local government revenues and employment since 2008 have dropped precipitously due to the recession, and competition for capital for worthy public projects is acute.

The biggest constraint on most local government finances, however, is on the operating budget side. Communities are searching for ways to reduce the day-to-day cost of government and operate with smaller staffs. This remains an opportunity for the solid-state lighting industry, whose products represent long-term maintenance and energy savings in annual operating budgets.

Although the “bleeding-edge” fear that has inhibited many governments from experimenting with LED has subsided, procurement policies that favor low base bid over life-cycle cost analyses remain. Many states are expanding opportunities for state contract pricing for solid-state lighting, helping smaller communities that are less likely to analyze long-term savings carefully. Communities often budget one to two years ahead of time for investments in infrastructure, so becoming aware of the budget calendar is a wise strategy for solid-state lighting innovators wishing to capture some of this market.

Future opportunities

A U.S. Department of Energy study published in 2008, “Energy Savings Estimates of Light Emitting Diodes in Niche Lighting Applications,” identified two niches where solid-state lighting can have the greatest energy impact nation-wide: street lighting and interior office lighting. Communities are making substantial LED investments in both. Los Angeles, for example, is in the midst of a 140,000 light streetlight retrofit project. U.S. DOE’s Municipal Solid State Lighting Consortium is followed by many local governments and offers excellent research and data on emerging new solid-state lighting product types. Office ceiling troffers and downlights are becoming competitive with fluorescent lighting in cost and are more compatible with building control technologies. Many states and electric utilities offer incentives for installation of energy-efficient light fixtures.

Raleigh continues to expand its investment in solid-state lighting based on a six-year track record of successful pilots, both interior and exterior. Facility managers are particularly interested in controllable lighting that can further leverage this investment through our building automation systems, and in ball field, indoor aquatic, and gymnasium lighting that meets competition standards. But above all, Raleigh is — as are many emerging cities — constantly trying to stay at the forefront of the use of technology to improve the lives of our citizens at lowest possible cost. Solid-state lighting has proven itself to be an important part of Raleigh’s strategy to remain a smart, connected, and efficient community into the future.    

Howe is the assistant city manager for the City of Raleigh, N.C. He can be reached at [email protected].

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