May 14, 2008

Report Author: Russ Doty

 

 

TITLE: LED Outdoor Lighting (Please feel free to copy the material herein to use in any report to your government concerning LEDs.)

 

 

Guess which side is LED light?

Which side uses 53% less energy at Prairie School in Racine, Wisconsin? http://www.betaled.com/docs/BetaLEDPB-Prairie.pdf

INTRODUCTION - PROBLEM/ISSUE STATEMENT 

Recent technology advances in solid state lighting (SSL) (aka.LED (light emitting diode)) lighting make it possible for us to reduce the energy used for street, parking lot & garage, and airport walkway lighting by between 25% and 50+% depending on the technology being replaced. Payback periods vary from 4 to 15 years, depending on they type of light replaced and maintenance costs. Those costs are coming down rapidly.

LEDs have a maintenance free life longer than the payback period. Free manufacturer’s demonstration fixtures are available as is DOE demonstration money. For these reasons, your governmental officials may wish to look at this new technology; to consider recommending that you apply to become a DOE host site demonstration project; and to consider recommending a trial LED street lighting program in your area.

·         The issue we are addressing is how to significantly reduce energy use in outdoor lighting while saving money for your government and its citizens by doing it.

·         If this problem is not addressed now, we will be wasting money and energy. It is an economic axiom when dealing with energy conservation measures that if the project financing can be obtained for the payback period, one creates an immediate positive cash flow in the budget by financing the project and paying to amortize the principle and interest with the savings. Simply put, if we do not do this we will pay more to waste energy than to save it. That is true in both the short and long run.

RECOMMENDATION

Therefore you may wish to recommends that you:

1) Apply to be a host site for a Department of Energy LED street lighting demonstration project before the May 31, 2008 deadline or during a later opportunity.

2) Ask staff to order and installing free demonstration fixtures for a 60 to 120 day demonstration project (depending on the luminaries being tested).

In addition, you may wish to evaluate this LED issue in the future with an eye to evaluating whether or not to recommend that consideration:

A) Requiring that street, parking lot and outdoor area lighting in all new development be LED lighting (as is being considered in Phoenix, AZ);

B) Requiring that LED lights be installed in all street lighting fixtures in your area that are being relamped or replaced after the DOE host or other demonstration project; and

C) Requiring that all public and private parking lots, garages and business walkways within your area that have been amortized or would have been amortized if they had been owned by a private utility be retrofitted with LED lights by August 31, 2010; and that all other such lights be retrofitted within a year following their amortization period or by December 31, 2013, whichever is earlier.

BACKGROUND

What Are LEDs?

LEDs (light-emitting diodes) have been around since the 1960s. You've probably seen them used as indicator lights in consumer products. Recently, however, they have become practical for general lighting purposes. Although they cost more upfront than the bulbs they replace, LED lights use half the energy (or less) and last longer than conventional bulbs, resulting in big savings and short payback periods. One specific advantage of LEDs is that they produce directional light. This gives us more control over what we light (i.e. the street) and what we don't (the night sky), reducing light pollution and wasted energy

graphic showing semiconductor chip

How LEDs Work

LEDs differ from traditional light sources in the way they produce light. In an incandescent lamp, a tungsten filament is heated by electric current until it glows or emits light. In a fluorescent lamp, an electric arc excites mercury atoms, which emit ultraviolet (UV) radiation. After striking the phosphor coating on the inside of glass tubes, the UV radiation is converted and emitted as visible light.

An LED, in contrast, is a semiconductor diode. It consists of a chip of semiconducting material treated to create a structure called a p-n (positive-negative) junction. When connected to a power source, current flows from the p-side or anode to the n-side, or cathode, but not in the reverse direction. Charge-carriers (electrons and electron holes) flow into the junction from electrodes. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon (light).

The specific wavelength or color emitted by the LED depends on the materials used to make the diode.

Red LEDs are based on aluminum gallium arsenide (AlGaAs). Blue LEDs are made from indium gallium nitride (InGaN) and green from aluminum gallium phosphide (AlGaP). "White" light is created by combining the light from red, green, and blue (RGB) LEDs or by coating a blue LED with yellow phosphor. See "Color Quality" section for more information.

Where are LEDs being used for Outdoor Lighting?

Ann Arbor, Michigan, a city the size of Billings, recently contracted for 1000 LEDs for $630,000 to replace existing metal halide (MH) decorative street lights. The contract was awarded following a 25-fixture evaluation from five manufacturers. It showed a 50 percent energy savings and 3.8 to 4.4 year payback on initial investment. The Mayor of Ann Arbor told NBC that after the payback period, the ongoing savings would be $100,000 a year. LEDs, which are warranted for seven years, are designed to last at least 10 years, in some pathway lighting applications, 23 years. [1]

Made in America, each LED fixture in Ann Arbor draws only 56 watts replacing bulbs that use more than 120 watts. [2] There is no lead or mercury in these fully recyclable LEDs. In terms of eliminating CO2, it was like taking 400 cars off the road.

Ann Arbor is also testing LED “cobrahead” fixtures more commonly seen in Montana for use in residential areas. The “cobrahead” payback period, from six years (Ann Arbor estimate) to 12 to 15 years (Oakland, CA), depends on fixture costs, energy prices and maintenance costs. However, the fixture costs are coming down 20%/year while efficiencies have gone up.

Welland, Ontario, Canada (50,000 pop.) experienced similar test run savings. It now plans to replace all 6,500 of its street lights in 3 to 5 years with Relume LED luminaires. [3]

Benton Harbor, MI (10,500 pop.) installed 46 LEDs in its historic downtown area.

Your area may be an ideal place for a DOE demonstration project.

ALTERNATIVES ANALYZED 

For outdoor lighting, three technologies have been used to replace general incandescent lights. Metal Halide (MH) lighting is considered the most inefficient. High pressure sodium (HPS) was the next technological advance. Several years ago, Northwestern Energy replaced MH fixtures in most of the areas where it owned outdoor lighting with HPS. The most recent technological advance has been to light emitting diodes (LED).

The pros and cons of LEDs are discussed in the various reports at http://www.netl.doe.gov/ssl/materials_2008.html

You have already seen a comparison of LED parking lot lighting with Metal Halide in the Racine, Wisconsin school pictured at the beginning of this recommendation. The LED lighting was on the left side of the picture. Here are light distribution comparisons between MH & LEDs for a parking lot found at http://www.netl.doe.gov/ssl/PDFs/Materials_2008/HAUGAARD_SSL08.pdf (p. 30)

 

Source: http://www.netl.doe.gov/ssl/PDFs/Materials_2008/HAUGAARD_SSL08.pdf

Source: http://www.netl.doe.gov/ssl/PDFs/Materials_2008/PAGET_SSL08.pdf

            What we learn from seeing the range of LED (SSL) performance is to not generalize. The specific Solid State Light (LED) in question might be quite adequate.

LEGAL, REGULATORY OR CONTRACTUAL REQUIREMENTS 

Montana’s Energy Policy is stated in:

90-4-1001. State energy policy goal statement. (1) It is the policy of the state of Montana to promote energy conservation, production, and consumption of a reliable and efficient mix of energy sources that represent the least social, environmental, and economic costs and the greatest long-term benefits to Montana citizens.

(2) In pursuing this goal, it is the policy of the state of Montana to:

(a) recognize that the state's energy system operates within the larger context of and is influenced by regional, national, and international energy markets;

(b) maintain a continual process to review this energy policy statement and any future changes so that Montana's energy strategy will provide for a balance between a sustainable environment and a viable economy; and

(c) adopt a state transportation energy policy as provided in 90-4-1010 and an alternative fuels policy and implementing guidelines as provided in 90-4-1011.

History: En. Sec. 1, Ch. 242, L. 1993; amd. Sec. 1, Ch. 311, L. 1995.

Other legal considerations may come into play if bonds have to be issued to finance replacement of existing outdoor lighting with LEDs. Implementation may also require a petition to the Montana Public Service Commission.

HUMAN CAPITAL REQUIREMENTS

This recommendation will require a person to apply to DOE if your area wishes to be a LED demonstration site. It will also require the street lighting supervisor to spend time obtaining offered demonstration fixtures. It will require approximately 2 hours of time for a two man crew to install each demonstration fixture.

Since LEDs are long lasting with virtually no maintenance, city maintenance costs will go down, largely because bulbs will not have to be replaced as often. There are some installation costs at least part of which should offset what would otherwise be maintenance costs during the installation period. However, for new installations, these costs are the same as they would be for installing a traditional outdoor luminaire.

Ann Arbor’s workers’ compensation rates went down 20% for some workers because they were not in bucket trucks as much fixing Metal Halide lights that lasted only two years. Some cities have experienced casualties involving traffic hitting the bucket trucks while workiers were maintaining lights. Ann Arbor also was able to free up workers who had been keeping the old lights operable for other maintenance projects.

FINANCIAL IMPACT 

With LED street lighting, Billings can lead the way by beginning to cut what is paid by 3,681 Northwestern Energy lighting tariff customers by up to 33% to 50% every hour the lights are on, an annual saving of approximately $800,000 to $2.5 million once the payback period is reached. [4] In the meantime our rates will not go up because the need to build a new power plant will be delayed; or Northwestern will be able to purchase less energy. And we will pump less CO2 into the environment.

Ann Arbor’s costs were $516 for the decorative LED bulb and are estimated to be in the $600 range to replace cobraheads. The full fixture cobra heads range in cost between $421 to $2,200 or more depending on the manufacturer, the fixture size and dealer markup. Since prices are coming down, one would have to obtain the type of MH or HPS light that is proposed to be replaced in Billings to be able to do a price and payback comparison including maintenance and future energy costs.

DOE presently has a host site program going that it is encouraging you to apply for.

Host demonstration sites receive technical guidance from DOE and help in evaluating technical, economic, and public acceptance factors to determine whether a project should proceed beyond the demonstration phase. Applications for this round are due May 31, 2008.

Guides for applications to become a host site for a demonstration project are at:

 http://www.netl.doe.gov/ssl/PDFs/IntenttoParticipate_HostSite.pdf . Also see

http://www.netl.doe.gov/ssl/PDFs/Materials_2008/TechDemos_08FS.pdf  and http://www.netl.doe.gov/ssl/PDFs/Materials_2008/CHADDOCK_SSL08.pdf (power point on how to prepare a successful application).

            Also, sections 554 to 558 of the Energy Independence and Security Act of 2007 ap-pear to provide opportunities for funding this type of program.

Demonstration bulbs: Since various manufacturers have no cost demonstrations available (except for the cost of installing the fixtures and uninstalling them and sending them back if they are not accepted), engaging in a demonstration will result in little financial impact on the city for a potential big gain.

Lumecon will make six lights available free for a 120-day trial period and even pay the cost of shipping them to you. See http://www.lumecon.com/index.html and call toll free: (877) 564-3133 or email: info@lumecon.com [5]

Leotec is willing to supply a single fixture under its test program/deferred billing program. If mounted where it can be viewed by the public and decision makers, it can have a positive impact with all interested parties. If it does not meet expectations, it can be returned anytime within 60 days.

Leotec advises that Billings will probably want a type III light distribution pattern, which it can deliver in 4 to 6 weeks. Most residential fixtures are about 100 watt HPS (~120 watts with ballast). Leotec’s Model SL125, which replaces that size, uses about 50 watts. The unit costs $421.

Other financing: Once the demonstration projects are complete, you will have a better idea of how implementation of this new energy efficient technology can be financed. Since some of the street lighting districts may be privately owned, some owned by the city and some by a utility, different approaches will be necessary.

Some luminaires can be replaced as part of maintenance; some can be installed in new development where initial maintenance costs are similar to installing HPS style lighting. As part of the demonstration, you may wish to investigate what existing lights are no longer in the utility’s rate base because their costs have been depreciated and what addition of new fixtures would do to rates if the utility could finance them at current low rates for long enough period so that the decrease in energy costs would be more than the cost of paying the principal and interest on the financing necessary to install the new infrastructure. You may wish to use a similar approach when consulting municipal bonding authorities concerning the city financing lighting replacement. Ann Arbor’s “Municipal Energy Fund” model deserves an in depth look. (See Attachment A.)

STAKEHOLDERS

Four main groups of stakeholders are affected by this recommendation to try LED outdoor lighting and convert to them, the citizenry in general, governments, electric utilities, and manufacturers of LED lighting.

Citizen Concerns: The public has received the quality of LED lighting favorably (with rare exception) when polled during trials of the products. This surprised the engineer who advised Benton Harbor, who changed from not favoring these lights to favoring them after the trial. See discussion of specific trials in Attachment A. The media and public have also reacted well to projected savings resulting from outdoor LED installations.

Governmental Concerns: When citizens are happy with the light quality, governmental concerns turn to whether the implementation of this technology makes financial sense. The total savings varies on the fixture used, its price, costs of maintaining existing lights and costs of switching to LEDs. Even places where early adoption several years ago of LED outdoor lighting was not a success have not given up on the idea and have continued to pursue it now that technology and prices have improved. Financial aspects of LEDs are discussed further in that section.

Utility Concerns: Utilities will lose sales if this recommendation is implemented. On the other hand they will be better able to meet demand side management goals and will have a reduced need to find additional energy sources as demand for electricity grows.

Since the US is moving toward the use of electric hybrid vehicles, the energy needed at night to charge batteries in those vehicles could come from the savings in reduced energy needed for outdoor lighting if LEDs were installed on a wide scale. That cannot happen if we do not act now to put the LED infrastructure in place to make the offset a reality.

A person from one utility in particular believes that “The technology is advancing, and maybe in the next five to ten years there will be a product developed for streetlights that puts out enough light without significant depreciation and is cost-effective.”

He is simply not up to date on his claims that LED light levels are inadequate, that LEDs are “far from being cost effective,” that independent tests of LEDs are not completed, and that the life of LED fixtures is about “7 years.” For a rebuttal of all these assertions, see the discussion in Attachment E.

LED Manufacturers: Product manufacturers undoubtedly have an interest in selling what they make. Utilities and at least one person from a testing laboratory supported by utilities assert that that interest should evoke caution when listening to manufacturer’s claims. And at least one utility would have us wait for results from the Seattle Lighting Lab tests. It asserts that the Seattle Lighting Labs is an independent testing organization. The Seattle Labs, while widely relied on in the utility industry are not independent since they are funded largely by the utility industry. If we are to be cautious about manufacturers’ product claims, we ought to also be cautious about claims of a utility that opposes adoption of products which would cause it to earn less by incorrectly claiming those products are not ready for prime time. We should also be told for example that the proposed Seattle Lighting Lab tests will be done inside in a room with a 15 foot ceiling that does not simulate the height at which many of these lights will operate. (See Attachment B)

Northwestern Energy personnel were apparently not aware of other, more independent LED testing. For example the Northwest national Laboratories (US Department of Energy) has engaged in four rounds of LED testing (some of which included outdoor lighting). (See Attachment B) Also, Northwestern did not make us aware of the testing done by other municipalities (See Attachment A), but did provide a memo from Santa Rosa, California personnel recommending against LED street lights. Points made in that memo have been addressed in Attachment F. Persons writing the Santa Rosa memo do not appear to be up to date with what has happened in LED lighting.

In addition, manufacturers have hired outside entities to evaluate their products. Those reports are available on some manufacturer’s web sites. (See Attachment D) In much the same way, Northwestern hired an outside entity (NEXANT) to evaluate its demand side management program which is available at http://www.northwesternenergy.com/documents/defaultsupply/plan07/volume2/Chapter3.pdf . If those reports are to be given credibility (or discounted) in the instance of LED manufacturers, then they likewise should be given credibility (or discounted) in the instance of Northwestern.

CONSISTENCY WITH ADOPTED POLICIES OR PLANS

Western Governors’ Goals: The nation is moving in the direction of more energy conservation and using renewable energy. The Western Governor’s Association estimates that its 19 states will need 30,000 MW of additional generation by 2015. It finds that more than 3 times that goal can be achieved from conservation and non-fossil fuel, non-nuclear power generation.  It has set a goal of 20% increase in energy efficiency by 2020. This LED recommendation will help the Western Governors meet its conservation target. http://www.westgov.org/wga/initiatives/cdeac/index.htm

U.S. Mayors’ Goals: As of May 13, 2008, mayors of 852 cities had taken Seattle Mayor Greg Nickels’ challenge to reduce green house gases to comply with the Kyoto Protocol. These mayors from all 50 states, Washington DC & Puerto Rico represent more than 80.1 million citizens. In Montana, former Mayors of Billings and Missoula and the present mayors of Billings, Missoula, Red Lodge and Bozeman accepted the challenge on behalf of their cities. As a City government, Seattle has already cut its greenhouse gas emissions by more than 60% compared to 1990 levels. This LED recommendation is one part of how your area may achieve similar reductions. http://www.seattle.gov/mayor/climate/default.htm#cities

            Montana Climate Change Advisory Committee (CCAC) Goals: The CCAC recommended policy options in two areas that would be well served by this Commission’s LED recommendation. They are RCII-1 (Demand Side Management Programs, Efficiency Funds and Requirements (and Financial Incentives)); and RCII-2 (Market Transformation and Technology Development Programs).

See also the Montana Energy Policy Statutes quoted in the legal section.

Northwestern Energy Demand Side Management Goals:  are hard to discern. If the search engine is working correctly, “goal” or “goals” are not mentioned in the 995 page report on NWE's demand side management (DSM) report http://www.northwesternenergy.com/documents/defaultsupply/plan07/volume2/Chapter3.pdf . So that report did not address whether or not NWE's DSM goals are being met and if not what additional measures would be necessary to meet them. The “… forecast annual growth rate for the Supply is 0.7% including DSM energy conservation impacts. If DSM impacts are excluded, the average annual growth rate increases to 1.3% for the 20-year period.” Estimating from graphs in its 2007 Default Supply plan, Northwestern supplied DSM reduced 2008 Load by about 15 MW; and displaced less than a million MWh in 2008. [Figures 6-1 & 6.2 http://www.northwesternenergy.com/documents/defaultsupply/plan07/volume1/chapter6.pdf .

ATTACHMENTS

ATTACHMENT A: LED PROJECTS

 

ANN ARBOR, MICHIGAN (114,000 pop.)

            I spoke with Mike Bergren (734-994-4918; mbergren@a2gov.org ) who is in charge of street lighting for the city. He said Ann Arbor has contracted to change out 1000 decorative globes (not cobraheads) in its downtown area. In order to not leave areas dark, 50 globes are taken down every other week and sent to Lumecon/Relume to be fitted with LEDs. Bergren thought that project would be completed in about a year. They chose to retrofit their existing decorative fixtures because they were quite nice costing $300 each and because the retrofit provided a directional mirrored quality light that has proved to be pleasing to the community.

            In the non-decorative lighting area, Ann Arbor is presently testing cobrahead lights from seven manufacturers for general street lighting. LED bulbs ranged from 70 to 150 watts. Ann Arbor plans to replace 250 watt High Pressure Sodium (HPS) bulbs with 90 watt cobrahead fixtures.

            Bergren will provide more detail in writing on Ann Arbor’s testing and financing.

Recommendation: Bergren said that several LED lights “out there” were substandard and cautioned others to be careful when purchasing. That however, has not prevented Ann Arbor from moving forward in requiring LEDs in new development areas and retrofitting with LEDs as the city can afford it, after exercising caution.

            Cost: The cost of cobrahead replacement is projected to be between $400 to $700 per fixture. The cobrahead payback will be around 6 years. The workers compensation cost for some went down approximately 20% in some rate classifications because workers diverted to other tasks rather than being in a bucket truck fixing lights were decertified from higher workers compensation rate classes. Ann Arbor had one fatal accident and a near fatal accident to workers in bucket trucks that were hit by passing vehicles.

            Financing: Ann Arbor’s downtown decorative lighting was accomplished with a $630,000 grant form it Downtown Development Authority. It is going to implement a “Lighting Bank” to finance retrofitting with LEDs in other areas. The city will require new development to insert LED lights and in addition, for the privilege of interconnecting the developer will pay $2,300 per 100 watts to the city. That money will be used to buy approximately five LED fixtures for the retrofitting program. The decline in costs from the retrofits will also be used to cover additional retrofits. Ann Arbor’s Municipal Energy Fund, administers that to ensure that a portion of the savings from the retrofits is paid back to the fund to pay for future retrofits.

            Energy savings: Bergren’s testing is revealing more energy savings for the cobraheads (70%) than the decorative lights (50%). LEDs avoid the HPS surge during startup and pulsing. Savings are from an adjusted flat rate per light based on an estimated 9 cents/kWh.

            Satisfaction with light levels: Ann Arbor’s decorative LED globes meet Recommended Practice (RP8) standards in the downtown area. He said RP8 standards are set for HPS lights which produce a yellow light. Lumens produced by HPS lights need to be as high as the RP8 standards because HPS light drops by 30% in a year as compared to lumens from LEDs taking 5 years to deteriorate 30%. Also light from LEDs doesn’t deteriorate much beyond 30%, while lumens from HPS continue to deteriorate to about 70% before being replaced.

Bergren said the RP8 needs to be adjusted for white light and for the fact that light output from LEDs does not deteriorate as much or as fast as HPS lights. That is the Recommended Practice for lumens from white LED light should be different from and less than from HPS. Extensive light level readings were performed by Ann Arbor, Detroit Edison and the University of Michigan. Ann Arbor did not just take the manufacturer’s word for lighting levels. It installed thermal couples to measure heat output and light meters to measure lumens. (Keeping heat output low is critical for long life in LED bulbs.)

            Bergren said he thought that the RP8 standard did not need to be met in residential neighborhoods where cobraheads are mounted on 30 foot poles. He explained that manufacturers were producing LEDs that would produce 80 lumens per watt during some of his testing and that has grown to 100 lumens per watt with recent models. He said manufacturers are shooting for 100 lumens per watt. I note that improvement in lighting level over the range of LEDs is borne out by DOE testing as well. See below for more comment on public acceptance.

            Maintenance: Since LEDs are sealed so bugs do not collect inside them. It is assumed there will be virtually no maintenance for the LED bulb lifetime. Ann Arbor used a spot maintenance program with two persons in a truck changing lights when they burn out. Its existing metal halide (MH) cobrahead bulbs had to be changed every two years and that it took a two man crew 2 hours per bulb to do that. This differed from Oakland which had one man in a truck doing mass relamping. So the payback periods in Oakland were different because the maintenance costs in the two cities were different. Mr. Bergren thought most cities could not afford to do mass relamping which changed bulbs whether or not they needed it.

URL for more info on Ann Arbor in its own words, see: http://www.a2gov.org/government/publicservices/systems_planning/energy/Documents/LED_Summary.pdf (which is reprinted below).

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ANN ARBOR'S LED STREETLIGHT PROGRAM

SUMMARY

The City of Ann Arbor is installing LED streetlights in order to reduce lighting costs and greenhouse gas emissions. After successfully piloting an LED replacement for our downtown ʺglobeʺ lights, the City received a $630,000 grant from the Ann Arbor Downtown Development Authority to fund retrofits for over 1,000 downtown lights. This initial installation will save the City over $100,000 per year, reducing annual greenhouse gas emissions by 267 tonnes CO2e. In addition, testing will continue on LED replacements for neighborhood streetlights, with the eventual goal of replacing all of our public lighting with LEDs. Full implementation of LEDs would cut Ann Arborʹs public lighting energy use in half and reduce greenhouse gas emissions by 2,200 tonnes CO2e annually.

PROJECT HISTORY

Funding for public lighting is increasingly difficult as electric costs rise and available municipal funds get tighter. In its 2005‐2006 budget, the City of Ann Arbor established a moratorium on new street lighting to help keep costs under control. City staff was tasked with finding ways to reduce public lighting costs. Like other cities, Ann Arbor had already replaced all its incandescent traffic signals with LEDs (light‐emitting diodes). As with the traffic signals, LED streetlights, if the technology was sufficiently developed, could create significant energy and maintenance savings since LEDs reduce lighting energy requirements by one‐half or more and last five times longer than conventional outdoor lighting technologies. In 2005, Ann Arbor committed to investigate LEDs for outdoor public lighting purposes as part of the ICLEI Great Lakes Climate Policy Project.

Initial research into past efforts with LED outdoor lighting in other municipalities like Honolulu and San Diego revealed failed efforts. These tests found that LED products had high costs and poor light output. To assess the current LED technologies, the city invited numerous LED manufacturers to provide test lights, which the City then installed at its own expense to evaluate the performance. Early lighting tests in 2006 were performed in the City Hall parking lot and showed improvement over the older LED technologies. Over the next two years, more successful technologies were demonstrated on city streets in the downtown area and in neighborhoods.

Over the last two years of testing, city staff has seen a tremendous improvement in light output and color rendition from LED lighting manufacturers. While lighting distribution and uniformity remain a problem for the highly directional LEDs, we have found applications where the LED technology is ready to replace existing public lighting today.

Tests on LED replacements for our downtown pedestrian ʺglobeʺ lights have been very       successful. This retrofit globe from Lumecon houses LEDs on four panels that face down and out, directing the light toward the street and away from the sky. Each fixture draws 56 watts and is expected to last ten years, replacing fixtures that use 120 watts and only last two years.

These globe lights are mounted on ten‐foot poles. As a test, 25 of these LED globes, purchased with help from our Downtown Development Authority (DDA), were installed to light one complete block in the Ann Arbor downtown.

With five times the lifetime and less than half the energy use, the lights have a 3.8‐year payback.

We are now planning to retrofit all of these downtown lights over the next two years. Funding for the downtown light conversions is being provided by a $630,000 grant from the DDA. The downtown LED project will reduce annual greenhouse gas emissions by 267 tonnes CO2e and save the city over $100,000 annually. The DDA grant will be administered through the Ann Arbor Municipal Energy Fund, which ensures that a portion of the savings from the retrofits is paid back to the fund to pay for future retrofits.

Meanwhile, Ann Arbor will continue to test possible LED replacements for the remainder of our streetlights. If the project succeeds in retrofitting all of the streetlights in Ann Arbor, the annual greenhouse gas emissions reduction is expected to be around 2,200 tonnes CO2e annually. All of the test installations have signs requesting public input, and the response from the community has been overwhelmingly positive. There seems to be agreement that Ann Arborʹs LED streetlight future will indeed be bright.

MORE INFORMATION: BENEFITS OF LEDS

The primary benefits of LEDs are their reduced energy consumption, longer lifetime, directionality and controllability. The energy savings are 50% or more and the lifetime is estimated at 5 times longer which yields the excellent payback time of 3.3 years. The ʺinstant on ʺ and dimming ability of LEDs will offer additional energy savings through control strategies that can brighten and dim based on time of day, ambient light, or any other control parameters desired. Motion sensors can turn LEDs on or off instantly, allowing lighting to be used only when needed. Typical outdoor lighting (MH or HPS) has a re‐strike time of a few minutes before they can turn on and therefore cannot be used with motion sensors. The City of Ann Arbor is partnering with lighting control companies to explore these new possibilities with LED lights. Finally, because LEDs emit directional light, we have more control over what we light (streets and sidewalks) and what we donʹt (the night sky). This makes for easier compliance with the Dark Skies Initiative, which aims to reduce light pollution and its associated wildlife impacts.

Our test globe LED fixtures use half the energy of the bulbs they replace and cobrahead fixtures use 50 to 80 percent less energy than our current cobraheads. This reduces emissions of mercury from coal power plants which leads directly to reduced CO2 emissions. Full implementation of LED streetlights could cut Ann Arborʹs greenhouse gas emissions by over 2,200 tonnes CO2‐ equivalent emissions.

One of the greatest advantages of LED fixtures is their lifetime, which reduces maintenance costs. At a ten‐year lifetime (compared to two years for a metal halide bulb), city staff will need 

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to change far fewer bulbs, ballasts, and igniters. In fact, maintenance savings alone are sufficient to make LED fixtures cheaper on a lifecycle basis than conventional fixtures.

MORE INFORMATION: LIFE-CYCLE COST ANALYSIS

 

Continue with existing bulbs (2 year life)

 

Number

Cost

 

Bulb replacements

5

$37

$186

Bulb labor & equip

5

$211

1,056

Ballast (10 yr life)

1

$59

$59

Igniter (10 yr life)

1

$35

35

Energy cost (4,380 kWh)

 

$325

 

 

 

 

$1,661

 

Change to LED bulb (10 year life)

 

Number

Cost

 

Bulb replacements

1

$460

$460

Bulb labor & equip

1

$  56

$  56

Energy cost (2,100 kWh)

 

 

$182

 

 

 

$698

 

 

 

 

10-year Maintenance saving

$819

10-year Energy saving

$143

Total

$962

 

Each LED replacement bulb saves $962 in energy and maintenance costs over its ten‐year lifetime. At this savings rate, the new bulb pays for itself in 4.4 years ($423 / $96). This analysis is based on our downtown globe lights, but initial inquiries into cobrahead fixtures suggest that the results will be even better.

MORE INFORMATION: TEST INSTALLATIONS

The first test fixtures that the City received and installed in our City Hall parking lot in the summer of 2005 were unimpressive. We got the sense that LED lighting manufacturers were not quite ready to meet our public lighting needs.  Over the following year, however, the test fixtures we received from manufacturers increased markedly in quality and today Ann Arbor is seriously considering moving to LEDs for public lighting.

The second test installation consists of a series of overhead streetlights (called ʺcobraheadsʺ because of their shape) in a residential neighborhood. These fixtures have not been purchased yet as the block of downtown globes have, but are instead on loan from the manufacturers. Wattages vary from 50 to 80 watts for fixtures that replace 250‐watt fixtures.

Manufacturers of cobrahead replacements currently installed for testing include Holophane, IntenCity, Leotek, Lumecon, and Millenia Technologies.

   

Leotec cobrahead                             Holophane cobrahead                             Lumecon globes

 

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To evaluate these fixtures, Ann Arbor is employing a four‐part test process, with lights being assessed on light output, heat management (which affects lifetime), and general public input.

Light Output: The cobrahead replacements are installed on a residential street where the spacing allows for each fixtureʹs light output to be judged independent of adjacent fixtures but where different fixtures can be easily compared. City staff is measuring light output and plans are in the works for a more involved public input process to evaluate the fixturesʹ aesthetics.

Heat Management: One of the most attractive characteristics of LEDs is their long lifetime, but this lifetime depends directly on the fixtureʹs operating temperature. As a result, heat management testing is vital to identifying fixtures that achieve our goal of a ten‐year life. City staff is measuring the operating temperature of fixtures to project the useful life of different test fixtures.

Energy Consumption: Each light is tested for electricity use in watts to verify energy savings.

Public Input: All the test installations have signs requesting public input, and the response from the community has been overwhelmingly positive (81 of 83 responses). The 81 positive responses emphasized the lack of light spilling out onto yards and house faces (ʺlight trespassʺ). One negative response commented that the light was too harsh. The other negative comment reflects a minority opinion about the purpose of public lighting, objecting that the LED cobrahead no longer lit up their garage and yard and that the globe LEDs were creating a ʺdark cavernʺ through the downtown.

CONTACT INFORMATION

City of Ann Arbor

(734) 994‐2700

Streetlights: Mike Bergren (mbergren@a2gov.org)

Energy Office: Dave Konkle (dkonkle@a2gov.org)

Holophane

www.holophane.com

IntenCity Lighting, Inc.

(479) 229‐0013

www.intencitylighting.com

LEDTronics

(800) 579‐4875

Leotek

(888) 806‐1188

www.leotek.co