Where the Northwest
shapes energy efficiency


Next Generation Street Lighting

Created 4/10/2013 by Rob Penney
Updated 5/14/2013 by Dave Yang
159 views • 0 comments

As part of BPA’s E3T project focused on emerging technologies, we worked with the Lighting Design Lab in Seattle to lab test many solid state and other new street light technologies and to build an outdoor test facility on an abandoned runway at South Seattle Community College.  The focus was to see how the various street lights performed—light distribution, glare, lighting levels, color, etc.  We also did secondary research on adaptive lighting for various applications—stairwells, parking lots, parking garages, area lights, etc.  But adaptive street lighting is a tougher nut to crack due to it being so tied to driving safety and so regulated as well as the difficulty in performing field tests on public streets. 

Looking at previous postings of this group, Charlotte was bold enough to try out controllable street lights.  Any of you who have heard David Crocket from there speak knows he’s pretty colorful.  “If we’d just done LED, that would be like putting rocket boosters on horseshoes because it’s an old design,” he says.  He is in the process of replacing 26,500 streetlights for $18M with an estimated a seven-year payback.  The City of Seattle, also known for its bold pursuit of efficiency, also worked to install LED street lights with adaptive control with great help from NEEA and expert Nancy Clanton.   

I also appreciated the videos Mark posted here from the Municipal Street Light Consortium last year.  In the first video, he articulates some of the many potential non-energy benefits of controllable street lights, modifying the lighting levels and colors for a wide variety of reasons and having each fixture report its condition.  Those veterans of the energy efficiency business know how important to push adoption of efficient products partly through their non-energy benefits that may dwarf the energy savings benefits. 

Now, working with the City of Davis, UC Davis researchers at the California Lighting Technology Center (CLTC) are field-testing a first-of-its-kind, fully adaptive street lighting system. The project employs adaptive LED streetlight fixtures and advanced, wirelessly networked lighting controls. Initial data indicates the system is reducing energy use by up to 42 percent, compared to static, single-level approaches to street lighting. The experimental effort is also helping researchers better understand how different sensors and communication protocols compare in responding to occupancy patterns and vehicular traffic. More information is available on CLTC's website: http://cltc.ucdavis.edu/content/view/1252

"This is the future of municipal lighting," says UC Davis Professor and CLTC Director Michael Siminovitch. "Lighting systems are becoming highly responsive to demand and use patterns. 'Adaptive lighting' significantly reduced energy use, but it also has the potential to reduce light pollution, enhance security, and lower maintenance costs. Still, there are too many cities are rushing to install LEDs but missing the opportunity to incorporate adaptive controls. That is why we need to work aggressively to advance 'controls on-board' designs as part of our national standards”

I look forward to efficiency leaders such as CLTC and NEEA as well as cities embracing sustainability such as Charlotte and Seattle to help the country to navigate the path forward to efficient and safe new adaptive street lighting systems with enough non-energy benefits to offset the higher initial costs.  Now that the huge Recovery Act grants that so many municipalities used to install LED street lights are gone and the focus on efficiency is waning a bit across the country, it will vital for us all to keep pushing forward to capitalize on the work of these trail blazers.  My goal, actively promoted by Michael Siminovitch at CLTC, is no more municipalities installing LED street lights without smart controls that will be “dumb” for decades to come. 

Rob Penney, WSU Energy Program

Log in to comment, rate, and share.
Comments (8)
Christopher Dymond on 04/11/13 on 04:53 PM (Pacific Time)
Thanks Rob - FYI I'm the new Product Manager here at NEEA responsible for advancing solid state street lighting with controls.  One of the details we are pondering here at NEEA is how to move LED's into streetlights now before the controls industry has settled down around a standards and become fully bankable with longevity equal to the luminaires. If you buy a fixture now that cannot be upgraded or is not "controls ready" then the opportunty is lost. My current thought is that we should pursue three tiers of products.  The first is a high efficiacy LED with a long life photosensor, the second is a luminaire that is controls ready and the third is one with a complete all in one smart controls solution. If the controls ready option emerges quickly it will take a large market share, if not it is likely that all in one solutions will take over because of their potential for lower overall cost and better integration.

The other bit worth sharing is that the work we did last year with Nancy Clanton and Virgina Tech has resulted in significant shifts thoughts on design light levels using LEDs with high CRI and color temperature.  In a nut shell the objectivly measure data did not indicate a reduction in detection distances using 4100K LEDs even when light levels dropped to 25% of the IES RP-8 recommendations on dry pavement.  On wet payvement the detection distances were still dramatically better at 25% light output than HPS at 100%.  This supports the principle that visibility has more to do with contrast and vertical luminance than horizontal illuminance.  We are actively supporting IES consideration of these efffects. If implemented they will allow a ~10% further reduction in total energy use.

I am very excited about this and welcome input.

Christopher Dymond, Sr.Product Manager - NEEA

Dave Yang on 04/12/13 on 08:20 AM (Pacific Time)
Thanks for the post, Rob.  

I was with electric utilities for 13 years and had street light engineering as part of my department, and went through IES coursework as part of my PE preparation.   I don't consider myself to be close to being an expert....  maybe I just know enough to comment a bit.    I am also the local rep for GE outdoor lighting fixtures, which includes the LED's.   the past 3 or so years I have been working with BPA and many of our utilities.

1). Controls -  I have spoken to a number of utilities about this.   My sample size is not statistically significant, but
          their concerns mirrored my own thoughts when I put my "utility" hat back on.   Absent nationally
          accepted guidelines for LED's, what is the liability to the utility if the utility "knowingly" reduces the light
          level and there is a resulting accident resulting in injury/death to a driver/passenger/pedestrian?   Utilities
          are always considered the "deep pockets" so awards will tend to favor the victims.   Utility section makers
          have a responsibility to consider this for their ratepayers and stockholders if applicable.   So, the
          additional energy savings might need to be considered with this concern.   All utilities I have discussed this
          with prefer to wait for the possible new IESNA RP-8 for LED's.   I know nationally, there may be utilities whom
          have moved ahead with controls.    I have discussed this with GE and asked them to consider expanding
          their controls options to maybe include motion sensors, etc. which could maybe return light levels to 100%
          for a short time when cars or pedestrians are detected.

2). Agreed that LED's in street lighting is a paradigm shift.   Unfortunately, most people are not aware of the full
          significance.     HID design/technology has been around long enough that the surviving manufacturers
          all pretty much have the latest in refractive/reflective technology, so a comparison of one fixture to
          another could be done by comparing total watts and/or lumens or a combination.   However, I find that
          most people continue to use this comparison technique with LED fixtures, which can be very apples- to-
          oranges".     The real goal is "visibility" as Christopher states.   With HID it was safe to assume that the 
          more lumens you have at the source, i.e., the fixture, the more footcandles you would have on the roadway
          surface and therefore better visibility.   This assumed the zenith in refractive/reflective design in everyone's
          fixtures, which is pretty much true.    However, with LED fixture designs there can be a huge disparity in
          how many lumens are actually delivered to the roadway surface.   Yes, fc's are only one factor
         in the ultimate goal of visibility, but it is very important.     Even though most applications will be retrofit, 
          it is very simple to compare fixtures by simply using any accepted roadway design software and the fixture
         data available at manufacturers' web sites.     As an example, for a local utility, we contrasted a GE LED
          Fixture proposed vs. a competitor who was slightly lower in $/fixture.   Using a 1,000 ft 2 lane road with
          sidewalk, and a goal of 1.3 fc/sq ft, 22 GE LED fixtures (and therefore poles, etc.) would be required.   
          Using data from brand X's web site, it would have taken 36 fixtures, etc.  obviously, their fixtures were
          not as efficient in getting their lumens to the roadway surface.   However, their lumens and lumens/watt
          were almost as much as the GE fixture.   So if these were incentivized with ratepayers or taxpayer money,
          more $ would have been spent and fewer kwh's saved.   There would have been an illusion of more kwh's
          saved w/ 36 fixtures when 22 would have sufficed.

Dave Yang

Rob Penney on 04/19/13 on 01:10 PM (Pacific Time)
I was pleased to see, Christopher Dymond, the Product Manager at NEEA responsible for advancing solid state street lighting, weigh into the discussion, and glad to see that he agrees about the importance of ordering streetlights that are "controls-ready".  I wasn’t clear if the “all-in-one solution” mention referred to adaptive controls fully integrated.  The results from last year’s study in Seattle indicating the municipalities can drop their street lighting by 75% and still provide motorists with the light they need for safety—that’s huge!  Just as with adaptive controls in parking garages, parking lots, and stairwells, there were understandable concerns about impact on safety but most folks have come around to seeing the great benefits of controllable lighting levels.  Although, like nuclear power, where safety is concerned the design and installation as well as operation and maintenance need to be done very well or this marvelous new controls technology will get a black eye when someone finds themselves in a dimly lit area.  And, as he points out, it’s important for codes and standards to keep up with and support technological developments so that the best solutions are not rejected by code officials. 

Dave Yang, another regular and welcome contributor here on Conduit, echoed this concern nicely—if a utility supports lower lighting levels and some child is killed in an auto accident will the lawyers dog pile on the deep pockets of the utility unless national standards build on solid field demonstrations to provide a credible defense for lowering lighting levels.  I also appreciate Dave’s cautionary note about LED cobra heads not all having equal ability to push the light out effectively with good distribution patterns.  Poor fixture optics result in closer pole spacing, and if the poles are existing that’s certain a large expense if not a deal-killer. 

As with all lighting decisions, keep your eyes open, do your homework, and share experiences with others in the business through forums such as this. In general, it seems that California is generally a few steps ahead of the country in pioneering a lot of lighting technologies, so it’s good to keep an eye on their progress.  One way to do that is to attend the Utility Energy Forum (http://www.utilityforum.org/), which is in Tahoe City, CA from May 15 to 17.  It’s a smaller gathering than most AEE or ACEEE events and regrettably conflicts with the BPA/NEEA event in Portland, which will be great, but the Forum may be worth considering for organizations that can send staff to more than one event.  It draws a number of senior-level technical and programmatic folks from the west coast, has a sizable session on new and emerging technologies, and is also a great time at the classic old Granlibakken ski lodge just up the street from Lake Tahoe.   

Rob Penney
WSU Energy Program
Christopher Dymond on 04/19/13 on 03:20 PM (Pacific Time)
It is likely that NEEA will assemble a technical advisory group to comment on SSSL initiative elements. I certainly welcome the input. Dave - your example about the imporance of design is well made and somthing I will seek expert input on.

To the point about liability -  utilitiies do not need to take additional liabilitiy if the design critera has temporal information in it.  The key to adaptive controls is to have the specifying engineer provide the design engineer with roadway occupancies by time of day. Advanced controls will then adapt the lighting levels to compliance with the design criteria - for the particular time of day.  What is classified as busy in at 8PM might be very low occupancy at 4AM.

It was an eye opener for me to realize that cities do not have to provide streetlighting, they need only specify what streets they want lit and to what standard they want them lit to and to implement a consistant policy.  Seattle City Light for instance has their own apporach that does not use RP-8. 

Adaptive controls will not progress as quickly as it has in Europe and Asia, but I do believe that it will occur for a sizeable portion of  roadays that are currently being lit.
Rob Penney on 04/22/13 on 03:03 PM (Pacific Time)
I'm glad to hear that NEEA will assemble a technical advisory group on this. We assembled one to look into this last year on behalf of BPA's E3T program and identified a number of issues, very briefly summarized below. You can see all the details on our website, www.e3tnw.org.
* First cost: LED lamps can be a lot more expensive
* Lack of ARRA funding: this extends payback over what it was a few years ago
* Need for new pole spacing in retrofits: Most LEDs may require closer spacing than existing systems, adding to cost * Improved light distribution and lighting quality of LEDs: this will hopefully lower IESNA-recommended lighting levels * Glare control: this has been an issue for some LEDs
* Lumen maintenance: what is it over LED’s longer life?
* Obtaining accurate performance data: lab testing can vary from claims of some manufacturers
* Rapid product evolution: should cities buy now or wait for next generation?
* Replacement parts—will they be available for the life of the lamp and will replacement lamps match original lamps? * Rate schedules & contracts: New ones may be needed so those investing in upgrade benefit from energy savings * Light quality: bluer white light may not appeal
* Warranties: why only a few years if product is claimed to last 10 years?

Rob Penney
WSU Energy Program
Dave Yang on 05/14/13 on 10:19 AM (Pacific Time)
Some other random considerations for what they are worth:  

Photocontrols – longer life photocontrols are available.   With long life LED fixtures, the photocontrol, or OLC (outdoor lighting control), becomes a “weak link”.    The cost (labor, overhead, etc.) to change out the common OLC each time can easily exceed the cost of the LED fixture.   Two large western electric utilities have gone to these long life OLC’s “across the board” for all fixtures, not just LED’s, due to this “maintenance cost”.  

LED controls – theoretically, the additional energy savings in reducing light levels when appropriate, is a very desirable goal.   Implementation involves some challenges.   A partial list of these challenges are:

*  As mentioned previously, liability to the utility.  Whether this concern prevents action or not depends upon each utility’s assessment of their risk.   Updated RP8 and RP20 guidelines for LED’s would be a major factor.  Until then, one approach seen nationally is assessing the existing lighting level using industry acceptable design software, and then choosing LED lighting that yields equal or greater footcandles (using the same design software).    The “average” is being used for roadways, and the “minimum” is being used for area lighting.  I believe this is consistent with what Christopher is suggesting …….  that lighting levels can be dropped to lower levels based on occupancies and time of day.   However, I believe the only defensible way to accomplish this is to either calculate all of this by hand or using an industry accepted design software.   This is a major blindspot for the greatest majority of electric utilities and municipalities at this time.   I see the greatest majority of these organizations proceeding without doing any of this.  Most people may not realize that street light “engineering” does not exist in probably 95% of these entities, so their LED decisions are being based on other criteria, which in all likelihood yields results totally different than what we are all discussing, i.e., they “do not know what they don’t know”, but they are convinced they know enough to proceed.   My personal opinion is that this is because the vast majority of decision makers in these organizations are no longer engineers so they do not have appreciation for what they don’t know.

Centralized or local control or both?   Some parties are interested in “smart” communications, however, there is no clear technology that can work for most organizations’ entire service territory, and they all come with pros/cons.  The comment about implementing LED fixtures that are “controls ready” is a good caution.   The challenge is that there are different technologies/approaches being attempted with no “clear winner” at this time.   So which “controls ready” technology does one include with their LED fixtures right now?

LED first cost – these costs are dropping rapidly……..FYI, as a rough comparison….. a 100w HPS cobra will cost about $70-120 each depending upon the channel it is purchased through.    A recent LED cobra fixture bid based on a large volume, the prices were in the range of $155 - $190 each.   A cautionary note…….there remains a much greater disparity at higher wattages.

Dave Yang on 05/14/13 on 10:22 AM (Pacific Time)
My apologies......I guess I am "wordy" today, but some other items which I believe are relevant.....  please just skip reading them if you don't find them relevant to you.......

Retrofits – in 100% of the LED projects I have been aware of, new poles have not been added.  This gets back to organizations’ lack of “engineering expertise”.   Some of these projects have proceeded because the ARRA funds were available and the projects had to be completed by a certain deadline.  Therefore, “engineering” was not done.   No one knows if even the existing RP8 and/or RP20 guidelines for HID lighting were even met.  In theory maybe more poles should have been used, yet maybe not.   Every reputable LED fixture manufacturer has multiple lighting patterns available.   Again, absent “engineering” most organizations are not aware of this, and they simply compare fixtures based on lumens of output or lumens/watt.    Not all manufacturers offer the same breadth of lighting patterns, so one manufacturer’s LED fixture might offer a lighting pattern that improves “visibility” using existing poles, but another manufacturer’s LED fixtures, that might be $5/ fixture lower in cost, might only have lighting patterns that yield worse “visibility” using the existing poles than the HID lighting they replace.  In virtually every situation I have seen so far, the selection decision has been based on lowest cost per fixture, and has not considered any of what is being discussed in this blog.

Glare – a very difficult topic, which most people do not realize.  For example, for roadway applications…… it is probably most important for drivers rather than pedestrians.   However, evaluators typically evaluate by standing under the various fixtures, which is more like a pedestrian.   One manufacturer has a design where in say, 2 of 10 positions, the glare is more, but in the other 8 positions it is much less.   Another manufacturer has the same amount of glare in all 10 positions.    The first manufacturer’s design was based on the impact of glare on a driver.    So which design is best?   This has not been considered by one organization yet that I have seen. 

Light level and uniformity – I believe everyone on this blog realizes now that LED’s are a paradigm shift in that lower average footcandles with LED no longer means lower visibility.   In fact in most cases, lower average footcandles, but greater uniformity, yields better “visibility”.   Even those who understand this paradigm shift may not understand where greater uniformity might/might not be desirable.   For example, would greater uniformity be good/bad in roadway lighting?   More recent findings have been that with greater uniformity it is more difficult to see a person in light colored clothing than dark colored clothing.   So might less uniformity be better in roadway lighting?   Greater uniformity might make more sense in parking lots with security cameras.

Lumen maintenance and certified tests – there is a standard that seems to be gaining industry wide acceptance ….. that the life of the LED fixture is defined at the point when the lumens drops to about 70% of original.   Do certified test reports help?   Sure, but everyone needs to realize these are still not a “guarantee” …… games can be played.  Any engineer who “certifies” incorrect test reports is in danger of losing his/her PE license, so that helps with USA manufacturers.   Would engineers from other countries be similarly “concerned”?
Dave Yang on 05/14/13 on 10:23 AM (Pacific Time)
The final thoughts......

Replacement parts – another point missed by many ……. Will the lowest cost manufacturer be in business say in 10 years?   A warranty only has value if that manufacturer is still in business over the life of that warranty.   Warranties of 5 years is typical, and 10 years is offered as well.   As with life insurance and actuaries…… the price for the fixture is more if the warranty is longer.   Same applies when you buy electronics……extended warranties are available if you wish to buy them.

Rate schedules/tariffs – another area that most people are not aware of.   Not as easy to implement as most would think.    Initially, when few LED fixtures are being installed, most utilities are doing rough calculations to determine the “energy” rate.   No one really knows yet how much should be charged for the “maintenance sinking fund”, right?  However, as more are being installed, some utilities are now having to go through the full process ……. Which involves a “cost of service analysis”, econometric modeling, and then some preliminary rate design.   Most organizations are not adjusting their “rates” very often so probably 95% of the organizations do not have any of this expertise “in house” or “on staff”.    There are only a limited # of consultants whom have the capability to do these analyses …….. so there is a fairly substantial cost, as well as an amount of time, that it will take to develop the formal rate schedules.  Also, because LED is so new, some electric utilities are initially not offering the same options to municipalities.    For example, recognizing that most municipalities do not have their own “linemen”, the electric utilities would offer an option where the utility would install the fixtures, maintain the fixtures, bill for the energy consumed, etc.   This option is not being offered …… so if the municipality proceeds, they have to hire a private contractor to install them.    Now who maintains them?   Probably the same contractor.   When the utility offered this option, the municipality would be required to abide by the utility’s specs, so replacement parts, etc., were readily available.   Without this option, municipalities are installing fixtures that the serving utility do not use, so the utility will not be in a position to assist in the future if there is a change in policy.

This resource is Public

Sector: Commercial
Function: Emerging Technology

Associated Groups:

All Things Commercial Lighting, Solid-state streetlights

Add to My Groups