Article by Scott Roos - Vice President of Sustainability and Business Optimization, Specialty Lighting Group at Acuity Brands. Originally featured in LD+A Magazine from the Illuminating Engineering Society.
There are many good, not-so-bad, and yet-to-be determined elements of sustainability that are helpful to understand when attempting to balance the quality and effectiveness of luminaire specifications and applied lighting design with their net environmental impact.
The Good
According to a soon to be published Green Light Alliance Life Cycle Assessment luminaire incubator study, Operational Carbon -- the carbon emitted from the electricity consumed during the use phase of a luminaire -- constitutes about 98% of the total lifecycle environmental impact from a luminaire.
Tremendous progress has been made on reducing lighting energy consumption through the vastly improved efficacy of LED technology, improved luminaire optical design that more efficiently directs lumens into useful zones, and the uptake of more granular lighting controls that ensures lights are on at the minimum required level only when needed. Our industry deserves a big pat on the back for our attainment and continued quest to reduce the energy consumption of our luminaires and applied lighting designs. And while many other metrics associated with sustainability are still emerging, specifiers design and predict the attainment of lighting energy use with great clarity, consistency, and project specificity.
A study by the Carbon Leadership Forum of a wide range of new office buildings informs that the lion’s share of the embodied carbon of a new building comes from its structure, sub-structure, and façade with LED luminaires only comprising between 0.5 to 1.5% of a building’s total.1 None-the-less, manufacturers have a responsibility to reduce luminaire embodied carbon through more innovative design and to publish their embodied carbon content to enable comparisons.
Calculating the embodied carbon of a luminaire can be a simple exercise and the TM65 Embodied Carbon Calculation Methodology developed in the UK is expected to become available later this year for use in North America. In the not-too-distant future it is reasonable to expect that a consistently calculated and comparable Embodied Carbon metric will become a standard piece of information on luminaire spec sheets. In the meantime, know that, in most cases, the number, size, and weight of the fixtures specified are a good proxy, i.e., if fewer, smaller/lighter fixtures are specified chances are good that embodied carbon will be reduced.
Circular design, in conjunction with a supporting circular economy infrastructure, eliminates waste and maximizes continual use, reuse, sharing, repair, refurbishment, and recycling to minimize resource inputs, waste, pollution, and carbon emissions. To help assess a luminaire’s attainment of circularity the UK based Chartered Institute of Building Service Engineers (CIBSE) developed a simple to use TM66 Circular Economy Digital Assessment Tool that evaluates a product’s design, manufacturing, materials, and supporting ecosystems.
The TM66 assessment tool, which can be downloaded from the CIBSE website, results in a score from very poor to excellent, providing a basis of comparing the level of attained circularity for two like-kind products. While we have a long way to go to achieve the full potential of a circular economy, TM66 is a relatively simple evaluation tool that should be expected to become widely adopted to aid both manufacturers and specifiers in identifying gaps and driving toward greater circularity.
Another “good” aspect of luminaire sustainability is the relatively minor role luminaires play in the overall material health concerns of a building. For the most part luminaires do not contain Volatile Organic Compounds or significant amounts of other chemicals of concern found in many other building products that are most likely to cause direct health hazards to building occupants.
Lighting specifiers that have concerns about the presence of particular chemicals of concern can prioritize the selection of fixtures that provide material transparency in the form of a Declare Label or Health Product Declaration (HPD), or for example, specify luminaires with PVC-free eco-friendly wire insulation and RoHS compliant electronics as disclosed on spec sheets.
Another “good” is that the steel and aluminum, which comprise the highest material content by weight in many luminaires, are produced from a high percent of recycled content and are infinitely recyclable with very high rates of recycling. Industry estimates show that in aggregate the recycled content of die-cast aluminum parts is 80%2, extruded aluminum 54%3, and sheet steel 25-35%4, which significantly reduces embodied carbon as compared to virgin material. Metals producers have every incentive to use as much recycled content as is available because it lowers their cost to produce.
And finally, Corporate Social Responsibility Reports (CSR) demonstrate progress in many areas including commitments to lower operational greenhouse gas emissions (GHG) using science-based targets working toward Net Zero.
The (Not so) Bad
Like any electrical product, luminaires do have some less than desirable chemical ingredients that manufacturers should feel obligated to identify and reduce, as the industry is starting to do. Looking at the list of ingredients in a typical luminaire one finds a lot of commonalities amongst fixtures from all manufacturers, regardless of whether they have embraced material transparency.
Most drivers from global suppliers comply with Restriction of Hazardous Substances (RoHS), a mandatory requirement for electrical components sold into the EU, meaning that hazardous substances are restricted to levels that reflect the current state of the art of electronics manufacturing. This is why Declare “Red List Approved” labels have an exemption for small electronics and why Declare “Red List Free” labels for luminaires likely earned that status by excluding the electronics, as is the case with incandescent socketed fixtures that ignore the ingredient impacts from the requisite LED lamp and for remote driver fixtures.
While the migration away from PVC wire insulation in luminaires is progressing slowly due to limited supply and significantly higher costs, it is helpful to have the perspective that the feet of wire used in luminaires comprises an infinitesimal part of the PVC used throughout a typical building relative to the miles of building wire, electrical boxes, plumbing pipe & fittings, flooring, window casements, roofing membranes, etc.
The additives used in plastics and coatings in trace amounts in many luminaires include a diverse group of chemicals, some of them chemicals of concern. Most of these additives are required to provide the necessary mechanical, thermal, electrical, optical, UV, flame-retardant, and durability properties with no environmentally friendly substitutes. While certainly an area for improvement, these small amounts are much less concerning than, for example, their greater use in building products such as fabrics, wall coverings, flooring and furniture which have more prolonged and intimate human contact.
Specifying fixtures that minimize the use of plastic components, including considering products using more innovative bio-based materials, will reduce the presence of additives and mitigate another “bad.” Most of the plastic used in luminaires are classified as #7 compound materials that cannot be easily recycled, which means they will likely end up in landfill, even if the luminaire has been perfectly designed for disassembly.
Likewise, currently the chances of drivers and other electronics in luminaires being recycled at end of life is very low because the electronics waste regulations and infrastructure are not in place to support wide-scale recycling for all types of electronic componentry, to include those found in luminaires. And the ecosystems needed to support the recovery, remanufacturing and reuse of complete luminaires simply don’t exist yet outside of a few small-scale pilots.
The TBD
An emerging sustainability metric for luminaires is a comprehensive Lifecycle Assessment (LCA) of the complete environmental impacts of a product over defined stages of its cradle to grave lifetime. The most accepted form of an LCA is called an Environmental Product Declaration (EPD), an independently verified and registered document that communicates transparent information about the lifecycle product impacts in seven categories as they effect the health of the atmosphere, water, and earth.
EPDs have been available for many years for a variety of high environmental impact building products and materials such as concrete, structural steel, glazing, and flooring. The rules and assumptions to create EPDs for luminaires in North America are still in development, although some luminaire EPDs using rules developed for Europe are starting to become available.
Theoretically, EPDs would enable lighting specifiers to make accurate comparisons of the total life cycle environmental impact of different luminaires. In practice there are many challenges for luminaire EPDs to be scaled in a meaningful and comparable way.
First, the significant amount of time and expense to create an EPD poses a challenge to scale them to large portfolios of fixtures and accurately represent the wide variety of product configurations and options within a product family. In the future, AI may provide an on-demand solution to creating configuration-specific luminaire EPDs.
Second, there are many yet-to-be resolved underlying inconsistencies that hinder both the accuracy and comparability of EPDs, including the use of different primary and secondary data/databases and variations in the software platforms used to collect/interpret data to name just two. Even the EPDs available for other building products caution that the results of like products are not directly comparable.
Third, the fact that approximately 98% of the lifecycle environmental impacts of a luminaire come from the electricity consumed during the use stage, something already well-characterized on a project specific basis, makes the value-add of Luminaire EPDs above and beyond TM65 Embodied Carbon Reporting and TM66 Circular Economy Assessment of questionable value.
Fortunately, a middle-ground solution in the form of Industry Wide EPDs (IW EPD), is on the near-term horizon. An IW EPD uses aggregated data from multiple manufacturers to characterize the environmental impact of a product type, such as a downlight, 2x2 troffer, or linear fixture. Since most of the impact in an EPD is from the use stage, manufacturer-specific embodied carbon differences will be an insignifant source of variation relative to the category average, making the IW EPD more than just directionally accurate. Simply specifying the highest efficacy fixture will result in achieving the lowest possible life cycle impact. If a manufacturer supplies data toward an IW EPD, which is not nearly as resource intensive as doing a product specific EPD, their product qualifies toward earning a point in LEED. Look for the first IW EPDs for several major fixture types to be published later this year as an outcome of the GreenLight Alliance Lifecycle Assessment incubator study.
Our industry is on an important journey to drive improved sustainability in the products that are designed, manufactured, specified, used and ultimately decommissioned. A lot of progress has been made toward reducing the dominant energy use or operational carbon impact from luminaires and their applied lighting and controls design. Emerging metrics will help improve understanding of the environmental impacts from luminaire embodied carbon and circular design attainment. And, clearly, there is still a long way to go to put the ecosystems in place to support a more circular economy that maximizes recovery, reuse, and recycling.
References
1. Life Cycle Assessment of Mechanical, Electrical, and Plumbing in Commercial Office Buildings April 2019. The Carbon Leadership Forum Department of Architecture University of Washington CLF-MEP-LCA-Report.pdf (carbonleadershipforum.org)
2. The Environmental Footprint of Semi-Fabricated Aluminum Products in North America Semi Fab LCA Executive Summary V2 12.7.21 (aluminum.org)
3. Aluminum Extruders Council EPD Extrusion EPDs/LCA | Aluminum Extruders Council (aec.org)
4. Steel Recycling Institute scrap-use-calcs.pdf (nerdsofsteel.com)
