True Green, or the New Dark Ages?
(As published in Retail Facility Business Magazine, February 2010)
By Ron Harwood, LC, IES
If "green is the new black," as some have quipped, it might be wise to pay closer attention to this metaphor for the fashion industry and extend it to its natural conclusion. For fashion is quickly rushed out and touted as the latest must-have, sometimes prematurely and often lacking staying power. And before you know it, money has been wasted on that which provides little in return.
And so it is with "green" lighting, as the industry - and even the government - rushes to introduce new lighting standards for conservation without taking an educated look at the technology at issue. While green pursuits are noble, often economically sound and certainly ecologically sensible, this "new black" we are seeing just might be the new "Dark Ages" if we don't proceed cautiously and astutely.
In recent months, the Obama administration has taken a very positive stance on energy conservation through the Energy Efficiency and Conservation Block Grants (EECBGs) to states as well as direct grant application offers given by agencies such as the Department of Energy. Many of the "Block Grants" allow, and some even insist, that a portion of the grant money be spent on the retrofit of existing light sources to more efficient light sources. Often, without specifically designating Light Emitting Diodes (LEDs) as the targeted new source, there are very few options other than LEDs that would be acceptable under the new criteria. In effect, the government has dangled a big carrot in front of cities and states, through grant offerings, to begin retrofitting street lighting and interior lighting with LEDs.
While LED light sources have made significant advances in the potential to save energy, they are still in the infancy stage of becoming the green lighting panacea at the present time. Therefore, there is a concern among professional lighting designers and utility companies that the current state-of-the art does not make an overarching case for hasty deployment. Issues of payback, efficacy and the quality of light are still not optimal. While energy independence is somewhat tied to energy efficiency in the U.S., using energy conservation methods without considering other important criteria is dangerous.
Light source energy efficiency is calculated by how many watts of power are consumed as a factor of how much light is produced, like gas consumption is a factor of how many miles one gets per gallon. Consider the old A-lamp light bulb that Thomas Edison invented that you used to buy in a hardware store. That incandescent source provides about 17 lumens of light for 100 watts of energy. Your utility bill shows the charge as the quantity of kWh, or Kilowatt hours, you have used during a month. If you burned a 100-watt light bulb for 10 hours, you would be charged for one kilowatt at a rate that varies in some states between eight and 12 cents per kWh. For ten hours of burning a standard incandescent light bulb, the charge would be between $0.80 and $1.20, or around a dollar.
Different kinds of light bulbs now produce light in a variety of ways more efficiently than the Edison invention. Incandescent is a glowing filament similar to a toaster that glows white hot; fluorescent is a source that creates an electrical arc within a tube that is catalyzed to produce light through the heating of a small drop of mercury within the tube that ultimately creates a glowing source. Similar to fluorescent bulbs, the Metal Halide bulb creates and arc that heats several semi-precious metals to create an arc that creates light; these also use a small drop of mercury as a catalyst. Both the fluorescent and Metal Halide lamps have efficiencies of around 80 lumens per watt of consumption, while the incandescent is around one fifth of that efficiency. New LEDs often produce light with the efficiencies of a fluorescent or Metal Halide source, but many are still much lower. Many of my friends and clients have already complained that when they purchased over-the-counter LED lamps from their local D.I.Y. store, even though the claims in the advertising said "saves lots of energy", the amount of light produced was sorely disappointing. Claims and disappointments like this abound in the retail marketplace; expectations have exceeded reality.
Clearly the best thing about the LED sources is that they do not require mercury as a catalyst to create light, making this aspect of the source a compelling argument for "going green". But the closer one looks, the more that we must be concerned about ubiquitous deployment of LEDs in all areas of our desire to save energy through lighting retrofits.
Many light output ratings of LED lamp sources are "raw data". This means that the actual light that comes out of a fixture will typically be less, or much less, than simply what the raw data would indicate. LEDs are very small and, typically, to provide the amount of light that would be equal to a 100-watt incandescent light bulb, many LEDs of one to three watts of consumption each would be used in the "bulb"; the lighting industry calls the population of LEDs that are clustered together a "light engine."
For street lighting, where the U.S. Government has provided grants for cities to retrofit their existing systems with LED light sources, dozens of LEDs are typically arrayed in a new fixture to provide illumination that is intended to replicate what we have become used to seeing.
The problem is that the output of an LED "light engine' is quite often no more efficient than the sources they are replacing. Their current efficiencies lie in the fact that LED light engines are better at directing most of their light in one direction. Imagine your garden hose and how, by adjusting the spray nozzle, you can shoot water much further by narrowing the stream; effectively, you are using about the same amount of water, but "focusing" it. Herein lays the core of most of the efficiency demonstrations that I have seen. Therefore, by the nature of how LEDs produce their light, it is much easier to focus their output. For highway lighting, LEDs look very promising. The poles are high and all of the light needs to be focused downward toward the highway. For small urban communities, however, most of the allure of being downtown at night rests with the illumination of the historic building facades. LED light engines are currently far less effective for this purpose, because they need to spread light in more directions than just the roadway to replace the existing light source.
When pressed for specific guarantees that an LED street light will compare in light quality and light quantity to an existing Metal Halide fixture, most manufacturers will become reluctant to make such a commitment, rather opting to place the attention on lower energy consumption and greater efficacy.
Light "quality" is also at issue. White is not the native color of most LEDs and a die or coating must be used to give off a white hue. Herein lies an issue that many utility companies are struggling with: that is, even if an LED fixture can spread sufficient light to meet the existing standards, the hue or color of the light seems either too blue or too green. Great strides are being made to adjust the light color to what we have become used to, but for now it remains a compelling reason to test the new LED sources in sufficient quantity to be sure that they meet appropriate visual comfort.
A third factor, glare, is also a very serious issue with many professional lighting designers and public utility executives. For decades, there has been an ongoing effort to reduce the brightness or glare that is emitted from the street lighting sources. Studies by the Illuminating Engineers Society in conjunction with the National Traffic Safety Board have shown that our eyes need time to adjust between the brightness of the light source and the darkness in-between the lights. This bright-then-dim driving experience tires driver's eyes and in some cases, creates a hazard known as "veiling reflectance," which can temporarily debilitate a motorist.
LEDs like Metal Halide sources are very bright, but the LED light source needs to "see" where it is aimed and does not use reflectors to bounce and distribute light so as to reduce glare. Many of the LED street light fixtures simply point the LED light sources in various arrays and angles to distribute the light directly onto the street, like miniature flashlights, creating a series of very bright spots emitting light. In time, this issue will be resolved, but for now, there is a danger in not being cautious of all of the criteria that has been used to provide safety and illumination for motorists in the past.
There is an initiative to also provide alternative light sources for government buildings and large corporate offices. Here again, there are many potential pitfalls to deploying LED light sources without caution. For many years, behavioral scientists, interior designers, architects and lighting designers have studied the human response to light in the workplace. First, when desktop computers proliferated in the office environment, fluorescent and incandescent sources created "hot spots" on the computer screens making it difficult to read. Consequently, new fixtures were designed to soften the glare and reduce eyestrain. Following closely with the notion that a well-lit workplace made people happier, created fewer headaches and reduced absenteeism, lighting designers found it en vogue to apply their skills to thousands of new and important additions to big city skylines. Sadly, there does not seem to be any reference to the use of Lighting Designers or Lighting Engineers in the grant offerings.
Currently, with all forms of retrofit LED based lamps (some that look like fluorescent tubes), there is a push to relight many offices to reduce energy. The problem looming in the near future is that by the time these retrofits are installed and working, there will be more efficient LED sources available. A source that looks better, operates cooler and perhaps has a faster "payback" for the initial investment.
The payback is a big deal. All LED sources in the form of light bulbs or light fixtures cost a lot more than their essentially less expensive fluorescent and Metal Halide counterparts. Yes, the existing lamps and fixtures will appear to consume more energy, but most of the LED products available cannot provide the same amount of light for a savings that results in a reasonable "payback." Most commercially available LED products have long life guarantees of between 30,000 and 50,000 hours, and some that extend much further. But these guarantees rarely cover the "retrofit" market and are based on exclusions such as environmental conditions, abuse and misuse factors that can be used to deny a claim.
Also, the vast majority of retrofit products are made by start-up manufacturers who may not survive the coming onslaught of major manufacturers like Philips and GE. These larger multi-national firms have been much more cautious about manufacturing LED products for mass consumption that do not meet even today's "old" lamp source efficacy. Moreover, many retrofit lamps do not spread the light as evenly as fixtures that use reflectors and traditional bulbs. LED lamp manufacturers have struggled to replicate the light beam distribution of traditional lamps and fixtures. This means that when you replace a fluorescent lamp with an LED lamp or "light engine" without caution, you can create a new version of Jimmy Durante's "good night Mrs Callabash wherever you are": spots of light where you once had even light. This simple problem can send our behavioral scientists back 50 years.
The issue least discussed is the safety of any existing fixtures that receives an LED retrofit lamp. Just because it fits in the fixture and "turns on" does not mean it is safe. All fixtures that comply with building and electrical codes have labels that include the specific lamps that have been tested by UL or other certified testing labs. Without the correct label and the correct tests, the safety of an LED source is not guaranteed and, effectively, not allowed by any inspection authority. The myth that LED light sources are "cool" has become a marketing ploy and is simply not true. LEDs produce a significant amount of heat that typically needs to be dissipated behind the light engine. Yes, they produce less heat within the light beams, but the real issue is that the heat all goes up. Moreover, many of light engines use a form of electrical transformer called a "driver". Most of the drivers actually have a shorter lifecycle rating than the light engines themselves - a hidden and dangerously underestimated future cost.
Not All Bad
There are currently a number of excellent uses for the new LED lamps and fixtures. Some are great outdoors for landscape lighting; they are wonderful as night lights in offices and stores where we just need to see for safety; and they are surprisingly good for task lighting in office environments on your desk or under counters. LEDs are now a very good alternative to neon in signs and for decoration on buildings. The best use of LEDs for safety has been in the traffic signal light, where long life and brightness are assets. However, the proliferation of this source was created by very, very good marketing. Coupled with the government unwittingly simply trying to induce energy savings and green practices, the U.S. government has the real possibility of creating somewhat of a disaster.
As we peruse the government funding opportunities, they find little or no reference to the control of LED light engines. Ironically, if all we did was control the new LED sources by adjusting the light output to the need for light, we have the possibility of an additional saving in energy and "engine life" of 50 percent more than the current predicted savings! Imagine all of the parking lot lights in America that burn at full brightness all night long. The current reason for this is that the parking lots were never wired in a way to turn most of them off after they are not filled with cars. Even the ones that have been wired in a more energy-conservative fashion still burn the lights left on at full brightness. The Metal Halide or other discharge lamps simply are not dimmable: LEDs are.
Instead of placing Stimulus funds in the hands of scientists and product developers, the hasty rush to save energy has put the cart before the horse. Of course we need cities and government buildings to begin the testing process, but the process needs to tie research and design to early deployment.
LEDs will be the great light source of the near future. The color and strength of the source will improve dramatically in the coming years. We simply need to use common sense in how we deploy LEDs with hard-to-come-by federal funds and our own hard earned dollars. It is a concern that, in the years to come, our hasty and perhaps unschooled deployment of LED light sources will have us all in the new Dark Ages with little or no money left to use LEDs when they are mature.< Back