Keeping Up With the Joneses: How Cities Nationwide are Lighting

Transcription

Keeping Up With the Joneses: How Cities Nationwide are Lighting
Keeping Up With the Joneses: How Cities Nationwide are Lighting Up and Saving
Energy
Key Points
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Consumers must be sure to exercise caution and good judgment, and conduct thorough research prior to purchasing lights.
The use of unconventional lights can actually make the use of other technology on a citywide scale easier.
Purchase costs are higher for LED and solar-powered lights, but they are more cost effective in the long run.
Every year, a significant portion of city funding is spent on outdoor lighting. According to
the U.S. Department of Energy (DOE), outdoor area lighting accounts for 8% of energy
consumed for lighting across the U.S. Improving outdoor lighting efficiency can
substantially reduce electricity use, as well as CO2 emissions, which can have
detrimental effects on environmental and human health. Many municipalities are
achieving the goals of increasing energy efficiency and reducing costs through the use
of light emitting diodes (LED) and solar energy technology.
In the past few years, many cities have used LEDs in traffic lights and other directional
signage, but technological advances are making the use of LEDs in other municipal
applications more practical and affordable.
High-pressure sodium (HPS) lamps are commonly used to provide outdoor lighting for
buildings, parking lots, commercial garages, streets, and walkways, despite the fact that
they are among the most inefficient fixtures available. HPS lamps, a type of highintensity discharge lighting, have an efficacy of 50–140 lumens per watt. The HPS lamps
have poorer color rendition than metal halide lamps, but longer lifetimes (16,000–
24,000 hours as opposed to 5,000–20,000 hours), according to the DOE's Office of
Energy Efficiency and Renewable Energy (EERE).
Making the most economically sound and environmentally friendly choice, cities across
the U.S. are following the trend of using LED lamps for outdoor lighting. Offering a total
package of a longer, 70,000-hour average life span, reduced maintenance and
operational costs, more vibrant color than conventional lighting, and great potential for
high energy savings, LEDs are the most promising new technology that can help municipalities achieve their efficiency goals in the
outdoor lighting sector and keep municipal light pollution to a minimum, according to the U.S. Environmental Protection Agency
(EPA).
WattWorks, an education-driven retailer of energy-efficient technology for businesses and homes, has recently undertaken a street
lighting retrofit project in the city of Powell, Ohio. Relume lights, which WattWorks CEO, George Anderson believes to be the “most
reliable and advanced LED technology on the market,” were used to retrofit two of the three types of outdoor street lights in the city.
Other U.S. outdoor area light fixture manufacturers include BetaLED, IntenCity Lighting Inc., Lumec, Schreder Group GIE, LuxBrite,
and the Lighting Sciences Group.
While it is too soon to measure results, Powell can expect to see a significant reduction in CO2 emissions, while experiencing a
notable decrease in funding spent on energy costs and maintenance, just as other cities have observed.
In 2006, the city of Ann Arbor, Michigan, installed LED outdoor area lighting in 100% of its downtown street fixtures as a part of an
LED pilot initiative. Testing LED technologies—the globe fixture, which uses 50% less energy (48-56 watts, compared to 100 watts of
conventional fixtures), and the cobra head fixture, which uses up to 80% less energy (50-80 watts, compared to 250 watts of
conventional fixtures)—Ann Arbor officials reported annual energy savings of 228 kWh per globe fixture, and 877 kWh per cobra
head fixture, according to the EPA.
The initial investment of $3.3 million has an annual savings of $700,000, with a pay back period of 4.7 years. Through the initiative,
Ann Arbor was able to reduce energy use by 80%. The EPA projects a reduction in greenhouse gas emissions by more than 2,200
tons of CO2 when Ann Arbor implements the initiative citywide. This will translate into an annual savings of 203 kg of CO2 emissions
per globe and up to 781 kg of CO2 emissions per cobra head, according to the EPA.
Powering up with photovoltaic energy, especially in the form of solar energy, has also become increasingly popular for street lighting,
as part of efforts to conserve energy, support a sustainable environment, and reduce costs.
Through the DOE's Solar Energy Technologies Program, and President Bush’s Solar America Initiative (SAI), 25 cities have
incorporated solar power as a major energy supplier for municipal street lighting. The program works to accelerate the development
of solar technologies, while making them more cost effective in all sectors by 2015. The initiative is supported by state technical
outreach programs including the Clean Energy Group, the National Association of Regulatory Utility Commissioners, and the National
Conference of State Legislatures. Outside of the program, solar-powered street lights and other outdoor lighting fixtures are popping
up more and more often.
The city of Fairfax, Virginia, has experimented with coupling LEDs with solar power as part of the city’s “Bus Stop Inventory and
Safety Study” initiative. While the program was initially put in place to increase visibility and safety for passengers, the city noted
other positive effects of the program. Fairfax found that the solar-powered LEDs were actually more cost effective than the
conventional lights that were used prior to the program and also significantly reduced energy use, which supported the city’s
environmental conservation initiative.
A typical LED cobra head fixture, commonly found mounted on brackets and suspended
over roadways, will be two-and-a-half to three times more expensive than conventional
lighting, but due to the extended life of the LED and substantially lower maintenance costs,
LEDs actually save money.
Some may shy away from LED lights and other high efficiency lighting due to the perceived
high costs, but WattWorks President, Don Hall, says consumers must pay for the quality if
they want to see better end results and reduced costs in the long run. “Incandescent lights
are kind of like disposable cameras,” Hall said. “They make them cheap, then you keep
buying the less expensive version repeatedly,
instead of doing it right the first time around.”
The current maintenance costs for existing metal
halide lights over a period of 10 years totals
$1,661, compared to $698 for LED street lights in
the same time period, resulting in 42% greater
cost savings for LED street lights, according to
the EPA. According to Anderson, under normal
use (operating approximately 12 hours per day),
LED luminaries should last about 70,000 hours,
or nearly 20 years.
“LEDs save energy, and significantly reduce maintenance. To replace a [conventional] light, you have to have police stop traffic,
bucket trucks, and workers to actually change the light,” Anderson said. “This labor is eliminated with LEDs. A city shouldn’t have to
employ a crew whose job is to drive around town and change blown-out lights. Bringing permanent LED lighting to the industry will be
very valuable economically.”
While decorative outdoor street lighting fixtures are available through select companies, due to the fact that many municipalities want
to maintain a certain theme or aesthetic for their city through previously established bulb styles, retrofitting lights is often the best
option, as opposed to buying new fixtures, according to Anderson.
In some cases, when smaller decorative styles are not large enough for the LED ballast, it is necessary for an entire lighting system
to be purchased, due to lack of space inside the existing fixture. An exception to the rule would be cobra head lights. This commonly
used style has become the standard for highway lights, so there are LED manufacturers that offer entire cobra head fixtures, in an
effort to eliminate the retrofit process. Anderson believes that, as the use of LED outdoor lights increase, more companies will aim to
meet the demand by designing more decorative fixtures.
Once the decision is made to purchase LED lighting, the tough choices have just begun. Consumers must be sure to exercise caution,
good judgment, and conduct thorough research prior to purchasing lights. When considering purchasing energy efficient lighting,
Anderson warns consumers to remember that “not all LEDs are created equal,” said Anderson. “There’s a lot of expensive junk out
on the ‘net that people have to watch out for.”
Purchasing fixtures that do not meet the minimum lumen threshold necessary to emit light levels equivalent to conventional lights can
result in greater purchase costs because more fixtures will have to be purchased to provide the same illumination, which defeats the
purpose of the high efficiency light. “Some companies spend a lot of time making [LED lights] look like traditional incandescent light
bulbs, but don’t address functionality, quality, and other issues,” Hall said.
There are still some issues to consider, even when quality light fixtures are used. Thermal management and power supply are the
most prominent issues facing LED use, according to Anderson. Conventional light is produced through heat. However, a
semiconductor, which can actually be damaged by heat, generates LED light. Heat at LED junctions is the primary cause of LED light
output degradation, which negatively impacts color and the life span of the light, according to the EPA, but new technology may soon
make this issue obsolete. “There are new fixtures available that actually place the heat away from the LEDs,” Anderson said. "This
ensures that the light will keeps its vibrancy and last longer."
The upgrades in lighting can potentially have a greater municipal impact than increased funding and reduced maintenance.
Hall predicts LEDs may actually further the practical use of other technologies, since the LED light is not heat generated.
“Some cities now want to go to a citywide WiFi network. An ideal place for this would be on top of elevated lighting poles, but you
can’t do it [with conventional lights] due to excessive heat and RFI,” said Hall. “No such interference exists with LEDs, so WiFi
transceivers could be placed on top.” Radio frequency interference (RFI) is a disturbance that affects electrical operations due to
electromagnetic radiation, which can degrade the performance of a circuit. This can be seen through light flickering when
conventional lights are used.
New LEDs can limit energy waste though lighting specific areas, rather than simply lighting an entire space. Hanging pendants,
lighting bars, and handrails with built-in LED lights to illuminate walkways, are just a few items on a long list of developing LED
technologies. Anderson suspects these technologies will be readily available and commonly used in the near future.
Despite perceived high costs, the popularity of LED outdoor lighting fixtures continues to grow as businesses and government entities
realize the substantial impact that the use of high-efficiency products can have on economic and environmental health. Hall predicts
this trend may evolve into a cultural movement, as more make the move to environmentally-motivated purchases.
“VHS and cassette tapes were really prevalent until DVDs and CDs came out,” said Hall, “but now you can’t hardly find anyone who
sells them. The same thing will happen with LED street lighting.”
WattWorks serves the commercial, residential, technical, and government sectors through educational seminars, and by offering
advanced, energy-efficient, eco-friendly technologies. Facility design consultations and specification reviews are also available
through the company to help assess energy needs and to find the best equipment to help achieve efficiency goals.
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