Overview of current trends and possibilities...

SEA has recently investigated the state of LED Street Light initiatives internationally as part of a request by eThekweni municipality. LED’s are a new technology, which could provide energy savings of between 30% and 90% over current lighting technologies. Their application in public lighting is still relatively new and being tested.

For further information on each city or product, please click the relevant heading for a link

A comment on a suggested strategy is included at the bottom of this page under Suggested Way Forward

LED Street lighting quick facts

Potentially use 30-90% less electricity and have 5 times the life expectancy than regular High Pressure Sodium (HPS) fixtures 

Light is easily controllable. Can be turned on and off instantly and can be dimmed for added energy savings at dawn and dusk

No mercury or other hazerdous chemical and gasses in the bulbs

Lighting is highly directional so that one can light areas that you want and not areas you don't

If Cape Town converted all of its streetlights to LED's and saved only 30% on the electricity, 27 Million KWh per annum would be saved, which equates to R8 640 000 per annum (at 32c/KWh) on electricity alone (does not include extra cost of the fixtures)

Summary of Cities

Raleigh, New Carolina

BETA LED Fixtures

Raleigh started with a pilot project using LED lighting in a parking garage, which had very positive result and they are expanding with this idea. In terms of LED streetlights, they are busy rolling out a pilot project installing LED streetlights on 2 blocks in the city. One block will be completed in September and the next one sometime next year.  Currently, Beta LED fixtures are being used. Daniel Howe suggested that the following key technical questions need to be addressed when assessing various technologies:

What are the DELIVERED lumens of the fixture?

What is the REAL input power?

Do you have photometric reports and IES files?

Have light output and color characteristics been validated by independent testing labs?

What is the CRI at each color temperature?

How do you ensure color consistency among fixtures built today or a year from now, or over the lifetime of the product?

Does the thermal management system keep the LED junction temperature below specified maximums in all applications?

There is not much further information available yet on their street light program as the first pilot is still being rolled out.

Oakland, California

BETA LED FIXTURES

In a residential area of Oakland a test project was setup where fifteen 78-watt LED (R4800) street light replaced 121-watt high pressure sodium (HPS) street lights. All the lights were 28.5 feet above the road surface, with spacing’s of 110, 120 or 165 feet between street lights. One street was illuminated with all new HPS lights. A second street was illuminated on one side with HPS lights and on the other side with LED lights and a third road was illuminated with LED Street lights only. The LED drew 77.6W while the HPS drew 121W, which would result in a saving of 178kWh per light replaced per year.

It was noted that the HPS provided more light directly below the fixture but that this level dropped faster with increased distance from the light source. The LED provided a much more even light distribution over the same area. Therefore, even though the maximum light level read under the HPS is higher, the average is similar between the two. The lumen depreciation over time was also less for the LED fixtures.

The following is copied from a correspondence with Joseph Hu, Electrical Services Engineer at the City of Oakland;

“Just to give you an idea of how we test our LEDs.  To compare our HPS street lights with LED, we ask the manufacturer to provide us with what they consider their 100 Watt, Type 3, cobra head, cutoff HPS equivalent LED fixture.  They must first submit their .ies file to us so that we can run it in our lighting calculation tool (AGI32).  We determine whether the LED lighting distribution is comparable to our HPS standard.  If so, we ask the manufacturer to provide 3 fixture samples for our field testing.  Field testing includes an initial 100 hour burn in period, then we mount the fixtures on our 3-30 feet test poles spaced 100 feet apart to one another.  We take lighting measurements using the same grid as the PG&E report (5 feet increments) and determine whether the actual footcandles come close to the lighting calculations performed using the manufacturer’s .ies file.  The goal of our field test is to verify designability using our lighting calculation software vs. actual lighting distribution.  Also, we evaluate the overall “feel” (such as lighting uniformity, color, glare, etc) of the lighting at our test site.

My personal recommendation is to source a few reputable LED manufacturers and test the fixtures out yourself.  I suspect the weather difference in Oakland vs South Africa will have a significant impact/difference in LED performance.”

Anchorage, Canada

BETA LED FIXTURES

On the 29^th of July, 2008, the city of Anchorage announced its participation in the LED City program and also announced a budget to retrofit all 16 000 municipal roadway lights with more energy efficient LED street lights. The preliminary studies have all been positive and the cost savings have been quantified. Anchorage is also using the BETA LED fixtures.

The city is currently being contacted for more detailed information.

Toronto, Canada

LUMECON FIXTURES

Toronto has rolled out a small test project for LED street lights where 16 have been installed to test their real savings, effectiveness and public response. The fixtures used were Leotek SL-250 fixtures by Lumecon (equivalent to the R7200 fixture). Electricity meters were installed within each streetlight. The 114W LED fixtures drew 146W while the 250W HPS fixtures drew 314W showing the inefficiency of the HPS ballast. The general public unanimously noted that the light quality was better than with the HPS lights and the surroundings could be seen more clearly.

The city is still being contacted for further information

Ann Arbor, Michigan

LUMECON FIXTURES

To evaluate the feasibility of LED street lights, Ann Arbor invited various LED street light manufacturers to provide LED street lights, which were then installed in the City Hall parking lot to evaluate performance. Installation costs were at the expense of the city but the fixtures were provided free of charge by the suppliers. The original products were not convincing but over a two year period, the technologies improved tremendously and Ann Arbor now believes that the current technologies are reliable enough to replace existing public lighting.

Downtown pedestrian ‘globe lights’ have been retrofitted with LED’s and have been very successful. The lights were retrofitted with Lumecon LED’s and draw 48 watts as opposed to the 100 watts of the original lights. The LED’s are also expected to last 10 years as opposed to 2 years for the original globes. As a test, 25 of these globe lights were installed to light one block of downtown Ann Arbor.

The globe light installations have a payback of only 3.3 years and there are plans now to retrofit all existing globe lights. Ann Arbor is still continuing its evaluation of LED technologies to replace other public lights throughout the city. From calculations, the fact that LED lights last 5 times longer than conventional ones results in enough savings alone to justify their installation and research suggests that the savings on the cobra-head fixtures will be even greater.

Ann Arbour is currently testing the following manufacturers for LED street lights; Holophane, IntenCity, Lumecon and Millenia. A four-part test process has been developed, which tests the following: Light Output, Heat Management (directly related to lifespan), Actual Energy Consumption, Public Input. The city has been contacted for further details but there has yet been no response.

The actual fittings used were not listed on the Lumecon website as they were specifically retrofitted for use in their globe lights.

Austin, Texas

LUMECON FIXTURES

Austin has many small projects using LED lights including parking garages, hallways signage and street lights although details of these projects have not yet been found. There is however a plan to begin testing fixtures to possibly replace the HPS Cobra-head roadway fixtures.

They have estimated that replacing 5 000 lights will save over $500 000 a year and this is only a small portion of all of the street lights in the city. Austin has an LED lighting rebate of $300 per kilowatt of capacity reduced.

Data on exactly which fixtures are being used as well as other details on the project are vague and awaiting clarity from the city.

Welland, Canada

LUMECON FIXTURES

Information on the Fitch Street LED streetlight project; 47 x Lumecon Type 3 Distribution LED by Relume were used. Installation completed in November 2007. Both R20 (90W) and R30 (120W) fixtures were used. The R20 corresponds to the R3600 data file and the R30 corresponds to a 120W version of the R4800 data file, which may be more similar to the R7200.

Third party validation of lumen output, lumen depreciation and colour temperature were performed and this was compared to that of the original high pressure sodium (HPS) lights. These tests were performed on site as well as in the lab. Tests were compared between new fixtures and those that had been running for 1000 hours. Door to door and online questionnaires were also completed to test public perception.

The results were generally positive. There was no lumen depreciation at 1000 hours but there was a slight increase. The correlated colour temperature (CCT) did however shift from 5991K to 7005K after 1000 hours. The CCT is a measure of the colour output and it is desirable for this to be stable over time. There were many results from the public perception surveys but overall, 73.1% of people questioned preferred LED street lights to regular ones, 7.1% may prefer them if there were some changes and 19.8% did not prefer LED street lights over regular ones.

Torraca, Italy

Torraca managed to convert 100% of their streetlights to LED’s in spring of 2007 using Cree XLamp® LED-based light engines made by Elettronica Gelbison and they are reporting a 75% electricity saving over their traditional lighting fixtures. Other information is currently unavailable or only in Italian. It must be noted however that Torraca is a small village.

A contact person has not yet been found and no technical data is available for their custom fixtures.

Tianjin, China     

Twenty graduate students, directed by Professor Pingjuan Niu, Ph.D., designed, produced and installed approximately 1,500 LED streetlights. These innovative LED fixtures were installed more than a year ago to illuminate 15 kilometres along the university’s streets.

Little other information is available or only in Chinese.

LED City Initiative

The LED City Initiative is a community of government and industrial parties, which are coming together to promote the use of LED’s in cities across a full range of municipal infrastructure. Below are the steps needed to become an LED City.

Steps to Becoming an LED City®/LED University(tm)

1) Identify a pilot LED lighting installation. Potential applications include:

You may wish to conduct a survey or solicit input from citizens and/or students to assess how the new lights are being received. Signs can be posted to prompt email feedback on light quality and safety issues. You may also wish to take before and after photography (professional quality) to help illustrate the dramatic difference in the new lighting.

Suggested way forward

This following outlines a suggested plan of action and the next steps, which need to be taken:

1) Identify costs of current lighting systems for new installations as well as mainenance costs (and regimes) as well as electricity consumption

2) Identify suppliers of the BETA LED and Lumecon fixtures as well as possible other local suppliers of LED Street Lights

3) Identify reported costs of LED installations and maintenance as well as electricity consumption from suppliers (Update these figures as real measurements become available)

4) Calculate cost-benefit of LED Street Lighting

5) Set up a physical test program (below)

SEA would suggest taking a similar route as suggested by Joseph Hu of Oakland, California. First locate and import (if necessary) samples of the Lumecon and BETA LED fixtures, which are most similar to the current street lights used in eThekweni. Then approach local suppliers to supply data, along with IES files, of their own products. Then test the IES files, along with those of the BETA LED and Lumecon fixtures, in modelling software. All the fixtures, which appear viable, could then be installed in a test parking lot or street and evaluated. The evaluation would include actual energy and light measurements over time as well as public response to the new fixtures. These tests would also give a clear idea of the costs of installing and maintaining the fixtures. The physical tests could also then be compared to the .IES files and reported data for the fixtures.

Once this preliminary test has been planned, the proposal can be sent to the various parties at the international cities, which have been identified for comment. After the comments have been received and considered, the proposal could be used to register eThekweni as an LED City Partner.

The pilot project could then be rolled out and assessed for expansion.

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