U.S. Department of Energy - Energy Efficiency and Renewable Energy
Building Technologies Office – Information Resources
Text-Alternative Version: LED Site Lighting in the Commercial Building Sector: Opportunities, Challenges, and the CBEA Performance Specification
Below is the text-alternative version of the LED Site Lighting in the Commercial Building Sector: Opportunities, Challenges, and the CBEA Performance Specification webcast.
Rosemarie Bartlett: Welcome, ladies and gentlemen. I'm Rosemarie Bartlett with the Pacific Northwest National Laboratory, and I'd like to welcome you to today's webcast, LED Site Lighting in the Commercial Building Sector: Opportunities, Challenges, and the CBEA Performance Specification, brought to you by the U.S. Department of Energy's Commercial Building Energy Alliances. At this time, all participants are in a listen-only mode.
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A couple of logistical announcements before we begin. You may ask a question at any time during the webcast today by using the Q&A menu on your computer. Questions won't be answered via the computer but will be answered live by the presenters as time allows at the end of the presentation. Lastly, during the webcast, you can hit F5 on your keyboard to enlarge your view of the slides. We're very happy to have as our speakers today Linda Sandahl, Eric Richman, and Michael Myer of the Pacific Northwest National Laboratory, and Ralph Williams of Wal-Mart. Our first speaker is Linda Sandahl, a program manager with PNNL. She has 19 years experience in supporting energy efficiency programs for the U.S. Department of Energy. Much of her work has supported the advancement of energy-efficient lighting technologies and practices. She currently supports DOE's Retailer Energy Alliance's Lighting and Electrical Subcommittee and the CBEA LED Site Lighting Working Group, as well as DOE's Solid-State Lighting program. Welcome to all of the speakers.
Linda, please begin.
Linda Sandahl: Thanks, Rose. Welcome, everyone, to today's Web presentation. We'll be talking about LED sit lighting in the commercial building sector, specifically about opportunities, challenges, and the Commercial Building Energy Alliance performance specification. We have four speakers today and the session will be followed by a question-and-answer session.
So let's go ahead and start with the presentation overview. I'm Linda Sandahl, and I will be talking about the Department of—U.S. Department of Energy's Solid-State Lighting program as well as the Commercial Building Energy Alliance, and I'll just be talking briefly about these programs and provide some resources where you can find some more information because the main focus of the presentation today is on the LED site lighting technology and the Commercial Building Energy Alliance performance spec and then providing some—an overview of LED site lighting demonstrations that have been completed by Wal-Mart. Eric Richman will be next up. He'll be talking about technology status and opportunities, followed by Michael Myer who'll be talking about the building—the Commercial Building Energy Alliance's LED site lighting performance specification, and both Eric and Michael have been very involved in both the Department of Energy's Solid-State Lighting program as well as the Commercial Building Energy Alliances. Finally, we'll have Ralph Williams of Wal-Mart talk about their LED site lighting demonstration projects. Ralph has also been very involved in the Retailer Energy Alliance and has been instrumental in helping develop the LED Site Lighting Performance Spec, which we'll be talking about shortly. Each speaker will introduce the next. I'm not going to give any more of a formal introduction to the speakers, so the person before them will give that introduction.
So let's move on to a little bit of background. In early 2008, the Retailer Energy Alliance identified LED site lighting as a project to pursue, and the Retailer Energy Alliance is part of the U.S. Department of Energy's overall Commercial Building Energy Alliance, which includes the Retailer Energy Alliance, the Healthcare Energy Alliance, and the Commercial Real Estate Energy Alliance, and these are all informal associations of building owners and operators who want to reduce energy consumption in their buildings. The Retailer Energy Alliance was really the first alliance to get started, and you can see here a number of the companies that are involved in this alliance. Again, the LED Parking Lot Lighting Project was the first one that we really got underway. You can see a link there, the buildings.energy.gov/alliances, that's a Web address you can go to and learn more about this. Also, we're working closely with the U.S. Department of Energy's Solid-State Lighting program and that's where a lot of the technical assistance is coming from, especially from Mike and from Eric in developing the performance spec. But if you go to the Web site that's included here, the www.ssl.energy.gov, you'll find a lot of resources on solid-state lighting, so I encourage you to go there to get a little more background.
Just some more background. Why LEDs may make sense for commercial building parking lots? One of the reasons we selected LED for parking lot lighting was because of quite a large opportunity we saw there and the retailers saw there: energy savings in terms of enhanced luminaire optical efficiency, better total system efficiency, control capability including deming, reduced maintenance costs, (There's a big savings over HID in terms of maintenance savings.) improved uniformity, environmentally friendly, no mercury in these products so that also equals lower disposal costs. But, and the big but here is, products on the market vary greatly in terms of their performance, so it's really buyer beware at this point. I don't know if any of you attended the Strategies In Light Conference a few weeks ago, but there were a number of presentations there on site lighting and just a lot of varied advice in terms of whether to move forward with site lighting, whether it was ready yet, and it certainly depends a lot on the product and on the application.
In terms of timing, REA, the working group, was established in April of 2008; and we completed a performance specification in early 2009, but we do anticipate that we'll be making some other updates to that specification. There are a number of demonstration projects underway, and you'll be hearing more about those from Ralph. You can also go to the Solid-State Lighting Web address on the previous slide. There's a lot of information posted there on GATEWAY demonstration projects that the U.S. Department of Energy has completed.
Finally, I wanted to mention in terms of our coordinated effort with the Commercial Building Energy Alliances, we're hoping to do some large coordinated purchases, probably summer 2009 and these would be individual retailers or other commercial building owners that use the specification that we've developed as part of this project to help make large purchases of LED site lighting, so be looking for that. That'll be coming.
Finally, I'm done with my portion and would like to introduce Eric Richman. Eric is with Pacific Northwest National Laboratory. He's a senior engineer and has extensive experience in the analysis and assessment of facility lighting and other system energy use. Eric currently chairs the ASHRAE/IESNA 90.1 Lighting Subcommittee and is involved in lighting test standards in development. Eric is lighting certified by the National Council of Qualifications for the Lighting Professionals and supports the DOE Solid-State Lighting program in a number of good capacities, including lighting measurement protocol and test standards development. He also provides technical support to the Commercial Building Energy Alliance's LED Site Lighting Working Group. So, Eric, go ahead.
Eric Richman: Thanks, Linda. What I wanted to cover today is kind of feeding off of the one slide Linda had on why LED lights might be good application for parking lots. I'm going to provide a little bit of background on the different attributes because sometimes there is some confusion about that, and then go a little farther and explain where the advantages and potential issues are with LEDs for parking lot and outdoor site lighting in general.
First of all, they truly are a good fit in a lot of respects, but I wanted to start off with a few basic potential issues or as I call them "Myths with LEDs." There's a lot of information out there on LEDs and it can be confusing, so I wanted to clear up just a few items in case you had heard some of these issues and had questions. The first one that you see a lot is about the life of the issue—life of the LED itself. First of all though just to explain, these LEDs are not a magic device. They are, which you may have heard, as a semi-conducting device. It happens to be unlike most other lighting technologies, it doesn't include a filament per se, it doesn't excite a gas like a fluorescent. It is a combination two different materials that when you excite the materials, they happen to emit visible light, which is what makes it unique. It has some advantages and disadvantages. In terms of the color, it's the combination of those materials provide different colors and the combination of those colors or the addition of a phosphor are able to allow that technology to produce a white type of light.
So on to these potential myths. The first one I'd like to talk about is one you've probably heard that they produce no heat, and that's of course not necessarily true. If you look at this chart, it kind of summarizes what happens with the energy in different lighting technologies, the major ones—incandescent fluorescent, metal halide, or HID products and LEDs. As you can see, the LEDs are doing pretty well in terms of efficiency, the visible light line at the top. But there are a couple of other types of energy that are radiated from typical technologies, infrared and ultraviolet. You don't see them, but you can feel them, and you'll notice they're fairly large components for the other technologies except for LEDs. They aren't radiating anything except for the visible light, and that's where the misnomer comes from that they don't produce any heat. If you look at the total radiant energy, it's pretty small for LEDs, and that's all visible light, the useful stuff. If you look at the total—the other heat energy conduction and confection and you'll see it's the highest for LEDs and what that means is the heat is not leaving the LED. You don't feel it, but it is there at the back of the LED chip and this in itself has potential problems. There's a potential for LEDs, so that's something to keep track of and be mindful of.
A second myth that you probably hear a lot is that they last forever. Well there's some truth to that in that they don't necessarily have catastrophic failures like a incandescent bulb or even a fluorescent bulb or an HID. They will tend to go on forever, but they will degrade just like any other lighting technology will degrade and the issue becomes then as they continue to survive, at some point they're going to be so dim or degrade so much that they're no longer useful to you. This chart is just an example showing there's a variety of different LEDs out there. As Linda mentioned, it's buyer beware. Some of them will have long lives, some of them at this point may not. The issue is they do not last forever for the purpose you may want to have for them, so you have to keep track of that carefully when you make a decision on what you're going to use them for.
A third major item that they're more efficient than other lighting, again not exactly, at least not yet. But that's the idea, LEDs are advancing rapidly in terms of efficiency. Going back to that initial chart, you'll see that LEDs are surpassing fluorescents, for the most part, and approaching metal halides. There's still some technologies like a low pressure sodium, a very monochromatic single color source that are still quite efficacious and LEDs are not quite there yet. But for the most part, they are approaching the efficiency of other sources. However, you'll see they are arranged, and this is another thing Linda mentioned, that you do have to beware, some of the products are just not efficient yet, some are better than others, so you have to be careful and watch out for what you're getting.
So to look at the some of the general attributes of LEDs that make them a good possibility for exterior lighting and interior, the energy efficiency of course we talked about. They are overtaking fluorescents. They certainly have some other advantages as well. Besides just the efficacy of the source itself, they have a directional component. As you can remember from a previous slide looking at the LED products, they don't emit in all directions. They are not like a filament in side of a round incandescent bulb, for example. They are truly a material sitting on a substrate that emits essentially in 180 degrees. They emit out in basically one half of a sphere or one direction. This has some inherent advantages in that you can direct the light where you want it. You don't have to take the light that's thrown backwards and then reflect it back out of a luminaire, for example. So there are advantages to that as we'll talk about a little later on.
Long life, of course, because they don't have the catastrophic failures, they can last for a very long time. Could easily exceed fluorescent and HID products, but again it's the degradation and how much light you're getting out of it at a certain point that you need to be careful of. This is very important issue for current applications.
Good lighting quality. Generally that's true with the white light products that are out there, they do have good color, which is tunable. You can make it easily to different colored temperatures that you want, and the distribution we talked about, the directional capability allows them to provide potentially a more uniform lighting pattern on the ground than most other technologies, which again we'll talk about. That's a true advantage of LEDs.
Breakage and vibration resistant. The LED chip or module itself is very vibration resistant, very tough to damage. However, these will go into a standard luminaire like any other technology, so it may be that the luminaire itself becomes the critical point, but the LED module itself is very tough, very resistant to damage.
Cold temperature friendly. As we talked about, a lot of the heat, the wasted heat for an LED is at the chip itself. So if you put that chip or module into cold temperatures, it tends to like that. It solves that problem of the heat, which if the heat was left on its own would create issues with the LED output and the LED life itself.
Another good attribute is it's instant on capability which allows for rapid cycling and other control options. HID technologies, which are common in outdoor applications, have slow start-up times, so they cannot be turned on and off rapidly. They also are very hard to dim or otherwise control. LEDs are quite the opposite. They are definitely instant on and they do have dimming capabilities. So all of those options are open when you go with an LED option or LED choice.
So what about issues? There are, of course, issues with LEDs, and we've hit on some of those. One of them is that the cost is still relatively high compared to other standard technologies which is a very large problem in terms of deciding to go with that choice compared to other standard technologies. Of course, the cost will ratchet down with time. Bulk purchases and when products become stable and uniform in terms of wattages and sizes, that will spur cost reductions. It's just like with any other technology, it tends to be expensive at the beginning. But as more people use them, the cost will tend to come down. One big issue now is looking at the maintenance savings to help support the choice to install these. Maintenance savings can be large for LEDs because they last—or potentially last such a long time. However because life is still being learned about it, we don't have enough data yet to really confirm life out to long periods like 50 to 100,000 hours or beyond, you need to be careful when you apply those maintenance savings and be rational and probably conservative with those for right now.
Life likability, like we were just talking about. We have limited long-term performance data so the actual lifetime abilities is still in question. However, the industries working on standards to help extrapolate what the life might be and more data is being created as we speak to try and solve that issue. Again, a conservative approach is probably the way to go at this point.
So let's look at some information on design criteria for outdoor applications, particularly for parking lots, which is a main focus. The little chart here is from RP20 on parking lot design. It shows that the basic minimum horizontal illuminance is recommended to be 0.2-foot candles. There is an enhanced security component which is higher than that. In terms of uniformity ratio, hot spots versus dark spots, 20 to 1 ratio is considered good for the basic installation. Now when you get to actual current practice of parking lots in the commercial sector, they typically run anywhere from 2-foot candles to 5-foot candles, and this of course exceeds the IESNA recommendations by about 10 times, which is a potential great energy waste. Conventional light sources that are used are typically metal halide or high pressure sodium which have relatively long lives and fairly efficient, but LEDs have some potential advantages over these. There are optic issues with metal halide and high pressure sodium in that you'll see typical hot spots and dark spots because they are a point source and it's just hard to distribute that light evenly because they are a point source. Of course, this uniformity or lack of uniformity between sites and within sites can create some problems and this is something that LEDs can help solve.
So let's look at an example. This is a modeled parking lot, modeled in lighting design software showing you a metal halide parking lot, same parking with LED lights. The first thing you'll see visually is the LED lot on the right has a more uniformed pattern. There are fewer dark spots and fewer hot spots. If you look at the actual numbers, the average is slightly lower for the LED system, but that's just the average. The maximum of course is lower for LED. The minimum is greater for LED, so you're going to have more light across the parking lot with this LED situation because of the uniformity. The max to min ratio of course has been reduced from 10 to 4.3, so this is one of the good attributes of LEDs that makes it advantage over other technologies. Of course the items that Linda mentioned in terms of saving energy, they certainly can save energy partially because of this uniformity. Reduced maintenance costs. That's true, but you do have to be careful. Improve uniformity, of course we can see that from the modeling. They are also environmentally friendly in terms that they contain no mercury, which is a consideration in today's world.
A couple other things I'd like to talk about, some things that DOE is doing to help move LEDs along as good quality products for the industry. One of them is an independent testing program you may have heard of called CALiPER, Commercially Available LED Product Evaluation and Reporting. The idea here is to take products off the shelf essentially and do our own independent testing of them and provide consistent results so that users can actually compare the characteristics of LEDs because currently because the test methods are emerging, there isn't a good consistent base of data for people to use, and this is providing that information. Just one example, this is some information on street lights, SSL 1 through 5 are five different street light products that incorporate LEDs. Also for comparison there was a high-pressure sodium in a couple of induction lamps tested. You'll notice that in the SSL products 1 through 5, there's quite a variety of efficacies, the lumen per watt Column 3, they range anywhere from a low of 19, which is not a lot better than incandescents, all the way up to 70, which far exceeds fluorescents and gets into the metal halide range as well, reinforcing the idea that there is a variety of products out there. It is a buyer-beware market, so you need to look at the data, and the CALiPER program provides this kind of data for people to use. Another program DOE is working on is the Outdoor Demonstration or Demonstration Project, which includes outdoor and indoor products or indoor applications. A lot of outdoor applications have been run through this program in various cities. What I wanted to show you was some information about one site in Atlantic City. This was an FAA demonstration site on a plaza and the current or the existing high-pressure sodium lamps were replaced with a 3-bar LED, and there were some results here showing that of course there was energy savings. The average illuminance levels actually went up from 3.5 to 3.6-foot candles. The maximum and minimums, as you saw in the modeling before, were reduced. The maximum was reduced and the minimum was increased. The max to min ratio was improved as well and of course there's energy savings. So this is the kind of information that the demonstration projects are providing and those are available for folks to look at, as well.
So what I'd like to do now is introduce you to Michael Myer, who's going to talk about the site lighting performance specification, and Michael has been with PNNL since 2007, came here with a master's in lighting from Rensselaer. He's also lighting certified by the NCQLP and Michael, who serves as a lighting engineer, comes to us with considerable experience in architectural lighting design and a lot of knowledge about lighting specializing in sustainable lighting design controls and newer technologies. He's been involved in PNNL-related work, including the Light Right Consortium and the DOE Solid-State Lighting GATEWAY Demonstration projects and provides technical support to the LED Site Lighting Working Group as well. So, Michael, it's all yours.
Michael Myer: Thank you, Eric. The CBEA LED Parking Lot Specification is rather—has a lot of parts to it. I'm mostly going to focus on some of the big ticket items in this presentation, some of the departures from standard practice, the new items, as well as some things that need to be addressed that are different for LEDs that may not be for other sources.
First, it is an application-focus specification, not a product-focus specification. So rather than saying: Oh, the luminaire needs to put out this much light or it needs to be this efficient, it focuses on what's the minimum desired illuminance for the site. Again in this case, it is minimum desired, not average. A lot of specifications focus on average illuminance, this one is saying, "What is the absolute minimum for it?" And that's a slight deviation. Certain specifications do it differently, so I just want to call that out.
One of the reasons why we're focusing on illuminance rather than trying to specify how the luminaires should perform is that modeling height and site layout effects lighting so the specification would not be different for a small fast-food chain versus a large grocery store. They're going to have different parking lots with very different pole layouts and not mounting height and so you need to have some flexibility. So by providing what the minimum illuminate is, it allows for similar specification for all those types of spaces, but allows for flexibility for the different retailers or commercial sites.
Next, how energy efficiency is measured is rather than trying to say that the luminaire needs to be X efficient or X illuminates per watt, this—that's a power density on the site at which is specified in terms of watts per square foot and that's installed watts of the luminaire. This allows the flexibility in the design so that the luminaire manufacturer or the designer, whose ever working on the exact installation, may be can pick between operating the LEDs at 700 million amps versus 350 million amps because there's advantages of one reason—for selecting one option over the other and so this allows—provides for flexibility, at the same time, achieves energy efficiency and savings by providing an overall cap on the installed power of the site. It is an application-focused specification but there of course needs to be some product-focus portion of the specification because the luminaire does play a role in achieving the specification. Some requirements that need to be about the luminaire include color characteristics, warranty, and reliability of luminaire, and we'll get into both parts of the specification shortly.
So this is an example of a typical parking lot for a building. In this case, it happens to be a grocery store. You can see that in the center of the site, there's the main parking area and then on the outside you, of course, have your perimeter parking area, and the area between the entrance to the store and the main parking area is the entry drive and then to the upper right on this drawing would be probably where your pallet area is or your (inaudible) drive, probably where the trucks come to offload goods. The specification is broken down by each—breaks down each section of the parking lot differently because there's different needs for each section. For instance, the entry drive is where your greatest conflict between vehicles and pedestrians are going to occur, therefore your likelihood for more increased traffic accidents is going to go up and so that has different requirements than the perimeter, and we'll discuss those shortly.
As I said earlier, the specification has a power density and illuminance requirements for the entire site. So in this chart, you'll see that on the left-hand column there are different lighting zones, LZ-0 to 4. LZ 0 would be a natural environment such as a national park where someplace where you don't want to disturb the environment with electric lighting. LZ-4 would be—is considered the most densely populated urban environment. I think downtown Los Angeles/Times Square, that type of thing and the LZ-1 through 3 fall in the range between those. There's a power density associated with each LZ and it goes up as you get—go up in lighting zone, that's because more light is needed and therefore more power's needed as you get to more density populated areas. Each of the parts of the parking lot also have again a minimum illuminance requirement, so you'll see, for instance, LZ-3, the perimeter parking lot has—perimeter parking lot wouldn't need 0.4-foot candles, and that's a minimum. You can exceed it, but that's what's required for a minimum. It's good to note—to point out that all of the illuminance requirements here in this table meet or exceed IES RP-20, and IES is the lighting body that publishes recommendations on lighting practices; and RP-20, as noted at the bottom, is the lighting for parking facilities, so there's a lot of flexibility and the power density limits what the overall (inaudible) power is increasing energy efficiently.
Another deviation in this specification than other standards or RP-20 specifically is RP-20 provides a recommended illuminance value of the average—of the maxed minimum illuminance requirements. So you… Under RP-20, you can have either a 15 to 1 or 20 to 1, depending on your security requirements, max to min, meaning that your lowest point and your maximum point can have roughly a 20 times difference in terms of illuminance. While those two, that metric only looks at two points, coefficient of variation is another uniformed metric that the IES has another lighting document. It's a statistical analysis of all the points on the site rather than just two specific points and so this specification requires a CV of 0.41, which is similar to a maxed min ratio of 10 to 1, and this is the formula of how you do it. For those people who are not statistically inclined, it looks scarier than it is. But really all you do is you take the difference between each point and the average point and you find what the difference is and that's what the standard deviation is and then you divide it by the mean illuminance value and it comes up with a value, and obviously the lower your CV, the more uniform or less distributed your values are. Again, it's a statistical analysis rather than just looking at two sole points for maxed and min.
Moving on to some of the luminaire requirements. Output and distribution is changed. In years past, we would have required a full cutoff luminaire or a semi-cutoff luminaire. The IES has moved away from the cutoff classification outright into what they now refer to as their BUG ratios or their BUR metric, which we'll go through more in depth in the next side. We'll also talk about color and the warranty and the luminaire requirements.
So this graphic explains the BUG metric. BUG's a great acronym, I really like it because it conjures up a great image. You have B which is backlight and trespass, so that's the light emitted behind the luminaire from zero being directly below luminaire to 90 being directly parallel behind the luminaire and then the IES now breaks down into different zones, BL, BM, BH, and BVH, and then you have your U which is your up light, which is either UL or UH, and they allow for different amounts of light in each of those different zones; and then you have your Glare which is the light coming out of the front of the luminaire which is FVH or FH; and if it's a symmetrical installation, it would also behind, as you see on both sides of this graphic.
Moving on to the specific requirements or the maximum illumine output in each of these zones, so for LZ-3 or LZ-2, you'd see that you were only allowed—the luminaire can only produce 100 lumens in the up light zone—in up light low which is the 90 to 100 degree range, and again 100 lumens in the up light high. This prevents or reduces the potential for up light and those are the problems related with up light. For glare, which is going to be the bigger issue in a parking lot luminaire installation are asymmetric luminaires, it gets a little more complicated. You have to find your different—your zone and then your different angles. So again, let's say in your Lighting Zone 3, which is probably the most typical lighting zone for this specification, and you'll see that in a asymmetric luminaire in the forward high, which is the 60 degree to 80 degree range, the luminaire can produce a maximum of 7500 lumens. In the forward very high, which is where you're going to get some of your most offensive glare, which is 80 degrees to 90 degrees, the luminaire can produce a maximum of 500 lumens. Then again this is an asymmetric luminaire, so in the back high, you can produce 2500 lumens and in the back very high again you can only produce 500 lumens. This is where the full cutoff class… The cutoff classification would have done something similar. This produces an absolute maximum and with the intent that by limiting the number of lumens, you reduce the potential for glare. Now this is not standalone to the CBEA specification, this is based on the IESNA's TM15, which is documented that redoes the whole classification system.
Moving on to the glare allowed in symmetric luminaires, you'll see that these values are very similar so that the 4 and high and the back high all have the same values and the forward high and the forward very high and the back very high again have the same lumen value. So again for LZ-3, you can—you're allowed a maximum of 7,500 lumens in the 60-degree to 80-degree range and a maximum of 500 lumens to the 80 to 90-degree range. Again, this is all about limiting layer, limiting up light or limiting light trespass based on absolute illuminance which is, and it works for different zones.
Moving on to other luminaire requirements, color temperature, which is just the appearance of the light source or sources, specification allows for anywhere as low as 2700 kelvins to 6500 kelvin, which is in line with ANSI C78 which is the chromaticity requirements for solid-state lighting. The CBEA specification does also require a minimum CRI of 70 or better. It is acknowledged that the CRI metric was not designed for LEDs, but we did include something in there to at least attempt to address CRI. Finally, the luminaire warranty is—requires five years or better on the luminaire and power supply.
Moving on to other photometric analysis, the manufacturer is required to provide two analysis, one is the initial conditions based on what the insulation would produce on day one and then a future conditions insulation, assuming light loss factors because it can be very different and shows kind of how the lights will fair over time. The luminaires also have to be independently tested per LM-79, which is the IES recommendations on how you actually test a solid-state lighting luminaire and the list for the (inaudible) approved labs that can do that type of testing can be found at that link. The manufacturers also have to submit data about how the LEDs were subjected to JEDEC reliability tests and JDEEC is initial. It's for an organization that looks at solid-state—just solid-state equipment, semiconductors really, and all these tests look at HTOL, for example, is the high temperature operating test so it subjects the LEDs to very high temperature LTOL is very low temperatures, running negative 4 degrees centigrade, and subjects the LEDs to a variety of intensive tests to make sure that the LEDs are not going to fail. Then the luminaire also should be subjected to a mechanical vibration test, numerous cycles and multiple Gs applied to the luminaire. Mostly this is not looking for a depreciation for light output; it's more looking for damage to luminaire as well as whether or not the light out which just stops overall. But again, it's to focus mostly on damage.
That was in quick just a review of the specification.
Now I'm going to turn it over to Ralph Williams, who's actually done—of Wal-Mart, who have done a number of installations already and he'll talk to some of the experience they've had on the ground with the equipment. Ralph joined Wal-Mart in 1984 as the first energy engineer. Ralph is presently a senior systems engineer in the Prototype Development and Construction Standards Department at Wal-Mart with the main focus of developing a more energy-efficient prototype in programs to decrease energy consumption in existing stores. Ralph also was the key contributor to the development of the CBEA LED Site Lighting Performance Specification. Here you go, Ralph.
Ralph Williams: Thank you, Mike. The use of LED style lighting in Wal-Mart is—or LED lighting in Wal-Mart is not a new project. We've already adopted LED for exterior signage, interior (inaudible) case lighting and have been evaluating and testing LED lighting in several areas of the retail environment such as LED spotlighting for the produce area, LED impact area lighting for apparel and home line displays, and using LED for ambulate lighting in support areas. Offices, bathrooms, sales areas, and support areas like deli and bakery are also being considered. However, one of our major sustainable lighting initiatives last year and continuing this year has been the evaluation and feasibility of LED site lighting.
Sustainability lighting journey began when our former Wal-Mart CEO Lee Scott's speech about three and a half years ago. In that speech, our building development team goals were established. Sustainable lighting is one area that has and will continue to assist the building development team to achieve these goals. As you can see from the slide, these goals have established due dates, they're 30% more efficient prototype is coming up real fast. Sustainable lighting also fits well with the higher level ultimate goals of our business to create ways to increase supply by 100% renewable energy. Sustainable lighting integrates into these lofty goals perfectly. Significant waste stream reduction by eliminating many fluorescent HID lamp replacements and when applied correctly can provide over 50% reduction in some building lighting loads. Reducing load no matter how small adds up and is a strategic part of the reality of being supplied by 100% renewable energy. LED site lighting is one step in that journey to assure that these goals are met.
Eric and Michael covered these areas, subjects very well. Lighting regulations and standards are becoming more stringent and because of that the lighting power density up light, trespass, et cetera, in addition to fitting well with our energy and sustainability goals, these regulatory trends were seen with every increasing frequency on many sides. Normally what happens at Wal-Mart sites when a poor or when a local ordinance and Wal-Mart site lighting standards different substantially, you get a very poor lighting design, 1000-watt fixtures on 20-foot pools, house side shielding on one, two, or even four sides, odd lamp sizes and mounting heights on the lots creating long-term maintenance issues.
Eric and Mike also covered this very well, why LEDs for parking lot lights? However this was presented by the first LED fixture manufacturers about LED site lighting and that sparked Wal-Mart's interest in LED. The smaller lumen packages and wattage reduction, better visual quality, and the even distribution of light, we could see that this would be very beneficial lighting qualities that would assist in creating a cost-effective, high-performing lighting solution especially with the sometimes ill-conceived local site ordinances. After several successful one- or two-pole tests to verify these LED characteristics, Wal-Mart made the commitment to do one full retrofit lot. We chose the Wal-Mart neighborhood market close to the home office with lower mounting heights and lamp wattages. The light had 400-watt pole start metal halide at 28-foot mounting heights and 120-foot spacing. The existing fixtures were replaced one-for-one with a GE 2005 watt LED luminaire. The picture shows the existing HID on the left and the poles retrofitted with an LED on the right. We considered this lot a big success. Confirmation number one, LEDs are more uniform. That's the pure and simple truth and this seems to be the basis for the lower foot candle acceptance. We've had no complaints or negative comments from anyone on this retrofit. Confirmation number two, the site was metered and confirmed what we already knew, LEDs save energy. In fact, using the CBEA LED Site Lighting Specifications, this percentage of energy reduction, 60% or more, is common in the actual and modeled site lighting performance from all manufacturers. Lower energy means lower average maintained foot candles but not necessarily lower minimum foot candles as had been shown before.
Slide 11 here, lesson number three, we were amazed at the cutoff performance with the LED fixture. From this site and with the GE luminaire, it was much easier to eliminate light trespass. On the left is the HID with house side shielding, notice the dark band actually on the parking lot surface just in front of the fixture. On the right is the GE LED fixture. Notice how defined the cutoff is just a few feet behind the fixture. LED will be as valuable for good neighbor policies which eliminate light trespassing cutoff and still provide good distribution with a luminaire profile, something that in the application of shielding has been difficult to obtain economically with HID sources. As a side note, I've outlined a bright light on the side of the building in the upper right of the picture on the right-hand side. This was a test with Beta security lights. The Wal-Mart … This is four bar 94 watt Beta fixture. The Wal-Mart standard is 175-watt metal halide lamp with full cutoff optics. With the lot retrofitted to LED, this was the first attempt at building mounted LED security lighting. As shown, the insulation was overdone a little. The code requirement for this area is one-foot candle maintained and we have 8- to 20-foot candles. More tests with a lower luminous/lower wattage packages in the next few months are anticipated. FYI: It's been our experience that obtaining an acceptable ROI is more difficult for building mounted security lighting as the average maintenance costs are not as high.
Back to our learnings. The security cameras tell the story very well. The vertical illuminance improves with LED. On the left hand … On the right hand side, those were actual before and after images from our security cameras. This slide didn't come together quite like I wanted, but as the majority of our LED applications today, the reduced maintenance is the basis for achieving the ROI for LED site lighting as a replacement for HID. This charts based on a 400-watt pulse start metal halide life characteristics which will represent the worse case as a retrofit with LED; 1000-watt pulse start metal halide had a shorter life characteristics. The jest of this story is what you've seen before, the actual rated life of the 400-watt pulse star metal halide is the second line at 4.5 years. The useful life of the LED or the real lamp cycle is the far red line at 10 years, 50,000 hours, and represents an lumen loss of 30% with essentially no LED fixture failures, hopefully. At this time, the HID has been re-lamped five to six times, that's the saw tooth along the top, and for this reason all the photometric evaluations are performed with around 0.7 light loss factor for LED which represents the design lumens or the minimum foot candles we want with—and that would be associated with a re-lamp cycle.
Based on this installed sites, LED economic and photometric performance over the 400-watt pulse start metal halide, the feeling is that the LED is ready for sites with mounting heights below 30 feet with 400 watt or below lamp wattages. For Wal-Mart this would include the Wal-Mart neighborhood market and sites with more stringent site lighting restrictions which put HID at a disadvantage.
Now where do we focus our attention? We had several tests of LED fixtures mounted at 42 foot. This is a site with four first-generation Beta 6000 kelvin Type 5 optics 12 light bar 306-watt luminaires mounted about 42 foot, the existing volt had two 1000 metal halide luminaires. Notice the blue (inaudible) LED light almost make the 4000 kelvin HID seem yellow. While the visual performance is OK, at this height and spacing, the system cannot meet the CBEA spec for minimum foot candles. This is the test with one pole with four GE LED fixtures similar to those at the neighborhood market mounted at 42 foot. The results are the same as with the Beta LEDs. Visual performance is OK, but at this height and spacing the system cannot meet the CBEA spec for minimum foot candles. These are both close but cannot meet the letter of the spec.
This is a very interesting test of a Lithonia 1000 watt one-for-one retrofit equivalent. We chose the pole location along the front drive (inaudible) because this pole location and lighting provides for higher illuminance level for the front drive (inaudible) as well as providing lighting for the building façade. This combination did meet the CBEA foot candle requirements. Again, the cooler temperature, color temperature is visible and the reduction and glare against the drop glass HID fixtures is noticeable. The left fixture does show that the façade lighting is adequate with this fixture. This information is directly from Lithonia and Wal-Mart has not actually verified the data; however, it does show exactly what we see and why LED has some much potential in site lighting, the distribution. As has been stated before, the average foot candles won't go down but not necessarily the minimum foot candle levels.
This picture I think is dramatic. It shows visually the elimination of the hot spot under the pole with the LED fixtures and even—and the very even lighting distribution across the front drive (inaudible). This is a photographic indication but not necessarily a control test to show the better visual performance of the LED fixtures; however this has been evident to some extent and all LED sites to date.
This leads to the question: Does Wal-Mart feel that LED site lighting is ready to roll out to our new and existing facilities today? Well, that's yes and no. Based on numerous evaluations, there were several factors that make a big impact on the financial and performance of LED over HID, the size and geometry of the parking lot. Larger lots are obviously harder to get the spacing that we need and the light level. Local ordinances and restrictions, light levels, pole heights, lamp wattages, lumen power densities all work well with an LED solution because, as stated before, normally are going lower. Finally, the cost of the LED system, that's still a big hurdle for our standard 1000 watt 42-foot mounting height with 160 foot spacing.
This is a good slide provided by GE, which does show today's cost and future possibilities for LED site lighting. 400-watt systems are very economical and 1000-watt HID systems are extremely economical to install. This is the biggest hurdle to deployment across the site lighting but one that a coordinated bid, perhaps among the RAA members a good specification of volume should be able to overcome. These benefits are hard to ignore and the base for our continued research and evaluation of LED site lighting.
The slide here is simply to acknowledge the Wal-Mart test and evaluate using the CBEA REA developed LED site lighting specification for all fixture and system performance criteria. We have 1000-watt test site plant to come on line in June of this year in Leavenworth, Kansas. This is the first LED site lighting test with a new site. We're partnering with GE and they were given—provided a site to design from scratch. The standard for the site would've been 1000-watt 42-foot mounting height. This site is also one of the more difficult for a LED to perform versus HID. It's a large site. The site was designed around the current CBEA specification that was when the site was developed. The design criteria is for Zone 3 power density and illuminance requirements. First thing to notice is that we did not meet our hurdle rates on this particular site, but it's a good demonstration for visual acceptance and learning experience for applying LED site lighting and adhering to the CBEA specification. The rear drive, the balanced storage area, the TLE parking areas along the side required extra poles and heads to meet specification criteria and that in turn increased the payback. The main lot which normally is not much of an issue for—with other site evaluations was for this site. The residential neighborhood along one side created location issues in the main lot. The parking around the pharmacy provided for pole setbacks that increased the number of poles and needs and heads to meet the specification and increase the payback. One of the things we have had a change in senior management and senior leadership, but our commitment to sustainability is still clear and strong as seen in the message from Mike Duke, our chairman.
I want to thank Lithonia and GE Lighting for assistance with the presentation, but at the same time make it clear that the content as Wal-Mart developed especially the financial expectations and valuation.
That concludes this portion of the presentation.
Rosemarie Bartlett: Well, thank you all very much for such an informative webcast—Linda, Eric, Michael, and Ralph, and thanks to all of you. The U.S. Department of Energy truly appreciates your attendance today. I note that several questions have come in as we went through the presentation, so I'd like to have Eric start us off with some of the questions that he had come in. Eric.
Eric Richman: Thank you. I think this is back on now. Yes, there are few questions. I will go through them here. Some of them are duplicates; I'll answer them as they come in essentially. One asked about glare metric, if there is going to be glare metric developed to handle additional glare that these might create. There have been a lot of discussions about glare for LEDs because they are a very small source there is the potential for additional glare. Anecdotal evidence out in the field has been mixed. Sometimes people consider there is more glare, sometimes they don't. it depends kind of on the architecture of the LED luminaire itself. In terms of an actual metric, there is a lot of information, a lot of interest in developing glare metrics, but there isn't anything specifically for LEDs at this time, but there is work within IES and others on somehow being able to characterize an appropriate glare metric for these, but nothing exists currently at this point.
Another question about—several questions, actually—about the environmentally friendly part of LEDs referencing mostly to the fact they don't contain mercury. It's true that LEDs have other components. They function and exist like most other computer chips and other electronic components which do have hazardous waste potential issues, a large one being lead and solder. Our understanding is that most LED manufacturers do not have these issues, but general material issues of the substrate and chip boards do exist so they would be disposed of just like any other computer chip, but they do not contain mercury. So the big environmental issue with a lot of fluorescent-type lamps does not exist, so there is one difference. But it's a good point that there aren't any disposal, specific disposal metrics yet other than to dispose of them just like any other computer chip.
In terms of efficacy, it was mentioned that LEDs are overtaking fluorescent efficiency, but the point was raised that there's some T8 systems that have very high efficacy at this point. That's true. That raises the issue that LEDs really are in flux, and there's quite a range of products out there. Some of them that are just emerging are approaching those efficacies; a lot of them are not. There is a difference here. They are essentially overcoming or have overcome compact fluorescent technology, but they are still approaching linear fluorescent efficacy, so the answer to that is it really depends on which product you're looking at.
One other question about the reference to RB-20 and common design practice and what has being seen out the field, the table that was shown does show the minimum value of 0.2 and the reference was to out in the field seeing values of 2 to 5. Those are mostly average values, not necessarily minimum values. So, yes, some of the parking lots may be hovering around the right value of 0.2, but a lot of those parking lots seen are at minimums of 2 to 5 as well. So truly most parking lots that are seen are well above what IES recommends.
Let me do one more here. Let's see, a good question here on: Since LEDs do not have catastrophic failure, they just continue to degrade over time, how is an owner going to know when the output is below an acceptable level? That's a very good point. That's something new with LEDs that needs to be addressed. One simple way, of course, is to continue measuring them. Of course, that's not very practical. Another method would be to look at the degradation curves that either are now or going to be provided by manufactures because there's a lot of interest in the life, which will give you an idea of when that point below which is—the point at which it doesn't provide the amount of illumination you were looking for is going to occur, at least give you an indication of that so you can either plan replacement of the product at that time or begin measuring it at that point. A good point, there's been a lot of interest in looking at ways to have the LED actually cutoff when it reaches that point; but currently, you need to either measure it or look at the degradation curve and determine when that point will be.
Rosemarie Bartlett: Thanks, Eric. Before I forget, I just wanted to mention that up on the screen right now are a series of links that you can go to for more information. Some of the links are rather long. So I just wanted to let everybody know that within the next couple of days, all of the attendees will receive an email, all of the registered attendees will receive an email and these links will be included so you don't have to write them down if you don't want to.
OK, so thanks, Eric. Michael, did you have any questions?
Michael Myer: Yeah, I received a couple questions while doing the presentation. One question focused on luminaire efficacy, why that wasn't addressed in the specification and it was more geared toward the power density metric. There are two answers. One is that by focusing on the power density, the specification can apply to the entire site rather than just a single fixture. We've discovered that in certain geometries, it's easier to light from the building rather than from a pole, so I don't want to use the word "wall pack" but some type of building mounted light might be able to provide sufficient lighting and actually help the situation and that may have different efficacy than a pole mounted fixture just because of sheer size. You can [inaudible] differently. So rather than trying to come up with that different thing, that was one reason why we went with a site-based specification rather than a single pole luminaire efficacy, though it could be possibly revised if there is a great interest for more luminaire efficacy. But moving more into why also luminaire efficacy gave us some concerns just coming up with one number was that because it's a site-based specification and every site is going to be very different, we need to take into account some of the geometry issues; and from our experience, what we're seeing in the field that a Type 3 optic or a Type 5 optic tends to have just slightly (inaudible)—because of the way the optics are designed, we've noticed some manufacturers have just slightly less output and so you have first you have some efficacies just between different optical designs, so that's one issue. Another issue of luminaire efficacy of why we didn't pick a single number is that you could also look at drive current. There might be some reasons why you would want to overdrive the luminaire such as if you were going to be using some type of thin occupancy sensor for high low setting where it would be on it kind of full when the spaces—when people are in the space; but when it's not being utilized as much, it went into a lower setting and because you're going to optimize your drive current that way, that would also affect your luminaire efficacy. Because there were a number of variables there focusing around just the actual luminaire efficacy, we tried to stay away from specifically stating one value and again trying to look at it more as a holistic site rather than just a fixture.
Another question came up about the specification and working with the MLO. The MLO, for those people that don't know, is the model lighting ordinance. It's currently out for public review, I believe April 10 is the final date for comments, I believe it's a 60% base comments right now, and we have tried to gear towards some of the LMO just because we know that it's coming and that many people will or some municipalities will probably try to incorporate it as well as or aspects of it so it's good to at least be aware of that. Along the same lines that the DOE ENERGY STAR, SSL ENERGY STAR specification for roadway and area lighting is currently being developed and in all practice, practical matters, if a luminaire qualifies for that, it should be able to be used in the specification and that also kind of alleviates some of the luminaire efficacy sides. But again, because every site's going to be different, we can't say that all ENERGY STAR luminaires are the best solution, it's just that they should be able to work and help meet some of the goals.
I'm just going to touch on two more comments or questions I received and then maybe turn it over to Ralph in case he received some. One was: Why is there 6500 K limit? That's a great question. Color temperature is always a fun discussion with LEDs. One is the ANSI specification, C78.377 which governs the SSL, the chromaticity of SSL products, allows for the range from 2700 K to 6500 K, so that's why we used the upper bounds. Another reason of just more than just following convention of what the ANSI standard was, also ENERGY STAR also references in that and we're trying to stay within kind of working conjunction with other programs. Another is that just 6500 K is also the upper bounds of I believe metal halide. I don't believe there's a metal halide or any other conventional source available on the market that has a color temperature higher than that, so I understand why that color temperature is kind of the upper limit. Also color temperature is just again—it's the color appearance of the light and so just because … Some manufacturer's abilities claim that higher color temperature means higher efficacy. That's not always true because the conversion of the phosphor doesn't always work that way. It trends that way, but it's not true for all LEDs or all designs.
There's another question about some possible negative environmental packs of high CCT colored temperatures. Again that is a valid concern. We know that different parts of the light spectrum affect people as well as fauna and plants differently. Flora and fauna, that's what I was looking for, differently and so rather than trying to have a conversation about higher CCT, I think the question if we're going to look at environmental impacts, maybe we should actually say, "Well, what about the actual spectrum?" and actually get in and talk about specific parts of the visual spectrum if that's the issue. At least from DOE's point of view and the work that we see come across, there is some research out there but not definitive research that says what the problem is for each specific group of plant, person, or animal and so that's why we allowed the range, again the range from 2700 K to 6500 K falls within the current practices of conventional sources of anywhere from metal halide and HPS all the way up to metal halide.
That was pretty much all the quick questions I received. Someone did point out a problem with one of the slides, and I appreciate that. So at this point, I have not seen Ralph's questions, so I don't know if he has any, but I'll turn it over to Ralph because he's the next on the list.
Ralph Williams: Thanks, Mike. Yes, I had a couple. First question were: What were the BUG ratings for the test luminaires, and the answer there is that I don't know. The Leavenworth, Kansas, is that really kind of our first full size that we will be doing all of this via demonstration hopefully with the DOE or just on our own to come up with publishing all this particular information.
The other was: On these sites, test sites, have you measured vertical illuminance? The answer there is no. There's also … It's all been visual. The reason being, it's difficult to figure out how to measure vertical illuminance exactly where we want to do it, and we are working on that as far as maybe in this site put a metrics, putting in vertical plane so that we can have a spot where we can go out and test.
The other is maintenance graph shows that there were several metal halide re-lamps during one LED lifecycle and the question was: Does the material make sense? Obviously, no, that would be a couple hundred dollars worth of metal halide lamps versus a thousand plus dollars worth of—for an LED fixture, but that's not the major cost. The major cost is the maintenance, is the labor to get out especially during spot re-lamps to get a bucket truck and electrician, get them to the site. That $20 lamp may be $300 by the time we finish. So when we looked at our average maintenance cost per site and worked them into our financials, that's what you were seeing. Those are the only two I had.
Rosemarie Bartlett: OK, thanks, Ralph. I know that there are other questions coming in fast and furious, and I know Eric has some more to answer. So, Eric, go ahead.
Eric Richman: A couple other questions here. One I believe was on one of the last slides in the first part about the FAA demonstration asking whether that was a one for one replacement with three-bar LED and, yes, that was. That was a direct replacement pole-for-pole.
A couple other questions here about mercury environmental friendliness of LEDs. Someone raised the issue that if you do replace a functioning fluorescent system, for example, with an LED system, you're going to inject more mercury into the environment, and that's true. That's certainly one of the issues you need to consider when you're looking at an LED replacement. Someone else mentioned that Canada recycles mercury from all fluorescent lamps so why can't the USA? Well the USA has some specific rules about recycling of mercury from fluorescent lamps. It isn't mandated for every fluorescent lamp like apparently it is in Canada. I wasn't aware of that. The USA, again, why can't the USA? They could. It just depends on the regulations. They are what they are for each state. I can't really say much more than that.
Another question here about comparisons with LED solutions compared to induction lighting. That's a common question on a lot of people's minds and there are some demonstrations being started to compare those two. The physical electrical attributes the two technologies are known, but there's still a question about how they perform in the field. So there are some demonstrations being started. No information yet that I am aware of.
How can … One other question here for me: How can individual LEDs be repaired? And a related question about: When you have to replace an LED, is it true that essentially the entire fixture goes with it? That's generally true because these are somewhat produced as a fixture of luminaire when they do end their useful life, whatever that may be in terms of what you're using them for, generally the LEDs themselves are not replaceable. Certainly individual LED chips or modules typically are not. There are some products where strips, for example, that three-bar luminaire might be one where you could replace one bar or all three, so there's work being done on producing replaceable LED luminaires, but a lot of them currently are you replace the head along with the luminaire.
So I believe Mike also has some additional questions, I'll pass it over to him.
Michael Myer: Thank you, yet again. Yeah, these are coming in pretty fast [inaudible] in real time. One question had to do with what is … What kind of value is considered over lighting for site lighting applications minimum or average? I don't entirely know … I don't understand the question. I going to give in two answers, then. If you're asking about site light trespass, the current specification actually provides a value, and I don't actually offhand remember what the exactly value is, but it's a—you'd take a measurement near the property line at a certain vertical height to get an idea of what the light trespass is and that's similar to the way RP-33, the revision to RP-33, which is exterior lighting, will have for light trespass. If it's a general question of: Well is there every too much light on a site, if that's the over lighting question. At some point, more light doesn't mean better. When you're dealing with low light applications, yes, a change between 0.1-foot candles and 2.2-foot candles is good; but when you get between 1-foot candle and 2-foot candle, it's not a marginal improvement that's worth going the whole 2 more foot candles, so it's different, a very different curve in terms of over lighting. So I don't want to say if there's something ever overlighted, the best answer is: What is the ambient conditions? If you're out in the middle of nowhere, you definitely don't need to light as if you're in the middle of a downturn urban environment. Your eye has a tremendous ability to adapt to the surrounds and so as long as people are keeping in with the surrounds, it's much easier to not overlight. Everyone hates the famous gas stations that feel that they need to produce more light for people to come there, and so that'd be a good example. The best example is overlighting is when your neighbors are not nearly as lighted to the same level you are.
Someone asked a question about measurement locations related to uniformity. The IES actually provides a document on how to measure parking lot applications as well as the CBEA specification on the CBEA Web site. We have an MNV* plan that I think because of a snowstorm in Colorado didn't get posted yet because they had some problems out in Colorado where the server is, but it's an MNV plan that'll actually provide guidance on how to take measurements in terms of site location, pole location, where to place the points, types of measurements to take. so that's in accordance with that. Then just about uniformity, if you're doing again to the CV method that we promote here, you don't actually… Again, the disbursement of points so the more points you have, you're just going to get a better set of data there.
Rosemarie Bartlett: Michael, I'm just going to interrupt you. I was told that that document has been posted.
Michael Myer: Thank you. I didn't know with the snow how things were going in Colorado. Unless anyone's listening from there, they can just drop me a line.
I'm sorry, these are coming in through my email so I'm quickly checking to see if there any other questions, but I think I'll hand it over to Ralph while I look for the next question.
Ralph Williams: Thanks, Mike. I did get additional question that said: On these sites or in Leavenworth, was any type of adaptive control employed to capture additional energy savings? No, we haven't. On these ... These were first-generation tests. Again, the test in Leavenworth was more for visual again acceptance of the whole site and just to as a functioning, I mean a real site where we took the CBEA specification and used that to design the site with. However in the future, this goes into several things. One of them was: How we would know when we're at the end of life, which is a big question? We do want to put a … We are working with several manufacturers of control systems to come up with a way of pushing the control of the site lighting down to the actual I'm going to say within the head itself and so both to eliminate day burners, which is a big issue, to understand the exact number of burn hours of LED light and also to either do some sort of lumen maintenance so that we can start off at a lower light level, a lower light level, lower output and then gradually increase over time as for the lumen degrading. But as far as turning lights on or off or going to a different power level, that's for retailers especially, I mean that's also kind of a lawyer question and we have—it's still up in the air.
Turn it back over to someone else.
Rosemarie Bartlett: Linda, I think you had a question.
Linda Sandahl: OK, my question is: Are there marketing tools available from the DOE to quantify the maintenance cost savings, including the elimination of the disposal cost? As we were developing the CBEA parking lot performance specification for LEDs, we did look into this. I don't think we have anything available publicly. I don't know if Mike or Eric knows if there's anything available at this point. We don't have anything on the DOE side, though.
Eric Richman: I'm not aware of anything. There may be, but I don't have any reference offhand.
Michael Myer: I think the maintenance cost would be more anecdotal because that's always going to be site-specific. Disposal is less site-specific; but at least in the GATEWAY demonstration program, which is another program I work on, we always look at maintenance costs and so say for instance the Eye 35 Bridge, which was a GATEWAY demonstration, the reports coming out very shortly, we did look at maintenance there, so that'd be one place. But again, that's much different than a parking lot. But I know that another parking lot demonstration in California was just completed and a report there was posted and there's some maintenance numbers there. Again, they're saying, "OK, this is what—how much we used to pay to maintain our metal halide, and this is the deferred cost and this is our payback." But again, it's all anecdotal because maintenance costs in Sacramento versus Leavenworth, Kansas, just cost of living is going to be very different. So it's not really more of a marketing tool, but there's some anecdotal separate things in the different GATEWAY reports.
Linda Sandahl: And those reports can be found on the DOE Solid-State Lighting program site on, and on the last slide in the presentation at www.ssl.energy.gov, you can look under GATEWAY projects and find those.
Rosemarie Bartlett: OK, thanks, everybody. Eric, you have a couple more questions, don't you?
Eric Richman: Sure. Few more here, questions and comments. One about: What about off grid solar, is the actual type question. I'm going to presume the person asking it was referring to: How would LEDs work with off grid solar? And they would work quite well. That's one of the potential advantages for LED is certainly for residential and maybe some remote sites in that because they tend to be a lower voltage source, they can work well with solar application so and a lot work has been done in that area.
A couple other items, someone mentioned sustainability of high cost and that's true. LEDs are considered a sustainable technology. They are at a high cost. Of course the idea is that cost will come down as time and people use them. So hopefully there's a point where those two items match.
One other comment here about someone noted that the first two speakers came over like an infomercial for LEDs. I would like to address that a little bit. We have of course and DOE who—the two of who provided the first two parts work for are trying to help support LEDs and make them a viable technology, but we are very careful not to overpromote. In fact, we find most of our time is spent trying to educate the public and industry on where they should put the brakes on if anything so they don't over-apply LEDs initially because, as we know from history, that causes more problems.
One other question: Someone asked about if you have an L-70 value for a certain product at a certain drive current, what value could you then assume at a different drive current? I would caution that you can't do any kind of general reductions or extrapolations like that. You would really need to go back to the manufacturer and look at their data or ask them to look at their data and provide you an appropriate value because it's not necessarily a linear extrapolation at this point.
So, Mike or Ralph, do you have any other questions you'd like to answer?
Michael Myer: Yeah, I have two more I'd like to get in and then I think I'll have covered most of them. One is a quick one. Someone asked about the section referring to light source expected life being 96%. The CBEA specification currently borrows from the ENERGY STAR, the DOE SSL ENERGY STAR expected life. It borrows it. It's not the same and the question is: Well is ENERGY STAR changing? Currently when you start talking about this extrapolation that Eric's referring to, you do a test at zero hours and 6,000 hours and then we try to extrapolate out. The ENERGY STAR one currently for residential fixtures is just looking for a pass/fail that based on the data it will last for 25,000 hours if it's residential or 35,000 hours if it's commercial and depending on what the number of hours is you take a different percentage. Well because we're looking for a longer life, we had to take a different percentage as well to get beyond 35,000 hours for the specification. Again, it's a pass/fail. It's not an expectation or extrapolation of what the depreciation would be at 50,000 hours. It's just saying, "Yes, it'll exceed this value." The whole reason why is that coming about is that currently the IES is developing TM-21, which is a document about how to extrapolate from this LM-80 data where… So they get all this data for 6,000 hours of operation or more and then how do you extrapolate out the life and until the IES releases that, ENERGY STAR is taking a conservative approach but moving forward and we're trying to kind of piggyback on that approach. But once TM-21 becomes official, that might be revised to reflect the current industry trend.
The last question that I'm going to address comes up a fair amount whenever we talk about LEDs, site lighting, or anything exterior. The question was that came in from many different people of between photopic, scotopic, and mesopic, well currently everything in the specification is based on photopic illuminance and everything we know about the photopic visual system. We don't really deal with scotopic in the specification because the scotopic visual system occurs at such low light level you can't actually get to it through our electric lighting, so that's really not an issue. But there is a way to do, if you dealt with photopic and scotopic, you took same measurements, you could then calculate the mesopic visual efficacy of the lighting installation and we did not deal with mesopic either for this installation because at the moment really the IES and the CIE are not in conjunction of the mesopic function and so we are taking the conservative of everyone agrees on photopic and so we're staying there. Maybe in the future when once the CIE and IES agree mesopic and there's a little more research, then things can change. But at the moment, we're just again being a little conservative and taking—using established industry methods.
That is my last question.
Rosemarie Bartlett: All right, thanks, Mike. Ralph, did you have any last questions or comments you wanted to make?
Ralph Williams: Yes, I had a couple of quick ones that said: Was wondering if Wal-Mart had national accounts with GE, Lithonia, Beta? No, right now we're working …The reason that we were working closely with these three manufacturers is because they had the wattage equivalents that would perform at the 28 42-foot heights. But we are working with any manufacturers that would bring a quality product properly developed and engineered and with all the stuff that we saw in the CBEA specifications as far as submittal information.
The other was, let's see, about using tie-in with photable take grids. Certainly something in the future that we would be looking at. We haven't done it lately or we haven't done it with any of these. The paybacks that we were talking about, we've done retrofits one-for-one or pole-for-pole, not exactly for one-for-one head, but pole-for-pole; and then the new store though, the Leavenworth, Kansas, probably wasn't elaborated on, that was a clean sheet and they were able—they was given the parking lot configuration. We did work with GE on that and they came up with a 35-foot mounting heights and sometimes four heads per pole. But replacement poles that we put in adding poles and retrofits or replacing poles and retrofits, the financial feasibility is just not there. So it has to be looking at existing locations. That's the ones I have.
Rosemarie Bartlett: OK, great. Well, thanks to all the speakers. Before I sign off, I wanted to go back to our very first slide, which does list the location that the handout is available at, and I wanted to also let everyone know that a video of this webcast will be available at that Web site within the next couple of weeks. So thank you for participating in today's webcast brought to you by the U.S. Department of Energy. You may all disconnect.