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Life Cycle Analysis Underscores Environmental Challenges of Plastic Pallets
New life cycle analysis by CHEP underscores environmental challenges of plastic pallets.
By Chaille Brindley
Date Posted: 4/1/2010
Over the last few years, a number of pallet companies have used Life Cycle Assessments (LCAs) to gauge the green credentials of various materials and systems. As expected, the results tend to favor the sponsor of the research. A recent study conducted by CHEP, the leading U.S. wood pallet pooler, showed some surprising results. CHEP’s 2009 Life Cycle Inventory (LCI) analysis results released in March 2010 showed some improvements of white wood pallets compared to both pooled wood and plastic although the results pointed to pooled wood (especially CHEP) as the most environmentally preferable and sustainable option.
When CHEP conducted its last LCI a few years ago, the research did not cover pooled plastic pallets because iGPS had just launched its U.S. program. There wasn’t enough good data to really analyze plastic at that point. CHEP’s new LCI indicates that both limited use and pooled wood pallets perform better than pooled plastic pallets in the major categories of solid waste, total energy consumption and greenhouse gases generated.
According to CHEP’s 2009 study, CHEP generates 48% less solid waste, consumes 23% less total energy and generates 14% less greenhouse gas than pooled plastic pallets. Compared with limited use white wood pallets, the CHEP system generates 50% less solid waste, consumes 19% less total energy and generates 5% less greenhouse gas.
Candice Herndon, director of environmental and regulatory affairs for CHEP, pointed to the higher number of trips as the primary advantage of CHEP over white wood. She also indicated that the high environmental impact of procuring oil and resin and manufacturing plastic pallets as the major disadvantage of plastic compared to limited use or pooled wood pallets.
“If I had to boil down the advantage of the CHEP system to two words, I would say it is ‘Source Reduction,’” Herndon said. “You are using less raw material up front, which means you have less disposal burden in the end. And the other major driver is the nature of wood; wood can be processed with low emissions and energy use. It is highly recyclable with an established infrastructure in place.”
A LCA looks at the entire life cycle of a product, from raw material acquisition to final disposition, rather than on a single manufacturing step or environmental emission. It quantifies resource use, energy consumption, and environmental emissions to the air, water, and land for a given product system, using a comprehensive and standardized methodology.
CHEP’s analysis examines CHEP pooled wooden block pallets, industry pooled plastic pallets, and non-pooled, limited use whitewood pallets. The assessment was conducted by Franklin Associates, a leading consultant group specializing in life cycle inventory analysis and solid waste management. CHEP’s most recent study was peer reviewed by Dr. David Allen, director of the Center for Energy & Environmental Resources at the University of Texas.
The life cycle inventory covers the following:
• Extraction, processing and transportation of raw materials
• Platform processing and manufacturing
• Transportation of the platform to the customer
• Use of the platform by the customer (including transportation cycles)
• End of life disposal or recycling
How Many Trips Can You Make?
The primary driver for any LCA of a pallet is the number of trips it makes. Herndon of CHEP said, “The one variable that changes everything is the trip rate.” The reason is that all the other variables are impacted by the number of trips.
In CHEP’s recent analysis, white wood makes up to four trips, pooled wood makes up to 30 trips and pooled plastic makes up to 60 trips before the end of its life cycle. These numbers stand in stark contrast to the assumptions used by iGPS in its 2008 LCA. iGPS assumed that white wood made only two trips, pooled wood pallets made 15 trips, and the iGPS plastic pallet made 100 trips. iGPS predicted its pallet would make 5-7 trips per year and would last 20 years. That is a pretty generous assumption in iGPS’ favor given the fact that so little data was available to corroborate its assertions as well as the fact that its pallet is not repairable.
Hartson Poland of PDQ Plastics, a plastic pallet company, said that most plastic pallets are warranted for somewhere between 2-3 years although they tend to last much longer. He added that some plastic pallets can last a lot longer than 12 years although he doubted that you could bank on even a heavy-duty plastic pallet lasting 15-20 years as the iGPS model does due to the rigors of the supply chain. Poland said, “Damage to pallets is all about kinetics, when a pallet gets moved. If a pallet is used consistently for 3-5 years, than its life span will be much less than a pallet that stays idle for much longer.”
Poland added that he has not seen wholesale failure of iGPS pallets yet, but that is far from being able to assume that most iGPS pallets will last 20 years. The Pallet Enterprise contacted iGPS, but its public spokesperson did not return requests for a comment.
When it comes to white wood pallets, both two and four trips may be skimpy in terms of real world performance. CHEP claims that its data came from a survey of pallet recyclers. But it is real hard to know the true life span of a wood pallet because variables can change so much from one pallet to the next.
Dr. Mark White, professor emeritus of Virginia Tech, said that the weakness of LCAs is the use side of pallets, especially for white wood. He suggested that a better way to look at it is to examine the manufacturing impacts of white wood, which are a much more knowable statistic. The lack of standardization in terms of lumber species used, board thickness and other factors make white wood much harder to quantify than any pooled pallet. Instead of an average number of trips, Dr. White suggested a wide range of trips may be a better way to examine trip potential for white wood pallets.
To CHEP’s credit, it refers to non-pooled white wood as limited-use and not single-use like iGPS did. Let’s be honest. With the prevalence of recyclers, most white wood pallets, even the really skimpy ones, make more than one trip. CHEP did double the number of trips in its recent analysis compared to what iGPS concluded two years ago.
I was told by a major pallet manufacturer in the East Coast that even eight trips is on the low side for many GMA white wood pallets. Realistically, if most white wood pallets only made between 2-4 trips, the number of recycled pallets in the market would be significantly smaller than it is. Truthfully, nobody has real good data on this point.
CHEP conducted sensitivity analysis measuring even the number of trips that iGPS estimated (100 trips) and discovered that pooled wood still came out on top, according to Derek Hannum, director of marketing for CHEP.
Hannum explained that most people who are familiar with the supply chain would say that 100 trips on a plastic pallet without getting damaged beyond use is a “stretch.” He added, “The bottom line is that with only a couple of years worth of operating data at iGPS, nobody really knows how long those plastic pallets are going to last.”
Hannum added, “Trips is one thing, but touches is another. In a grocery supply chain, we have conducted studies that show pallets can get touched up to eight times at the distributor level alone.”
White Wood Improvements
CHEP’s latest analysis indicates that the gap has closed between CHEP and non-pooled wood pallets. A major reason is that CHEP used new numbers indicating that the number of limited use wood pallets going into landfills has significantly reduced. These numbers were published last year in the Pallet Enterprise in an August 2009 article titled “Pallet Recovery, Repair and Remanufacturing in a Changing Industry: 1992 to 2006.”
The other major reason for changes in the numbers is higher repair rates that drive up input costs. CHEP is doing this in response to customer request for improved pallet quality. Hannum said “We are repairing 50% more pallets today than a few years ago. In pallet repair, we are using more energy and generating more waste per average pallet trip. We’re okay with that because it’s a direct response to the changing needs of our customers and CHEP remains the most environmentally sound choice.”
This analysis focused on typical GMA situations where a standard pallet can be fairly easily retrieved. The analysis doesn’t really factor in construction sites or other one-way shipping situations and exceptions. In those instances small numbers of pallets are shipped to locations where they are not economical to retrieve. These scenarios may favor one-way and not pooled pallets due to the transportation distances and high cost of retrieval.
Input Materials at the Point of Manufacture
A major negative for plastic is the higher input costs and environmental impacts associated with pumping oil from the ground, processing resin and manufacturing a plastic product. This could be the one place where CHEP’s assumptions could vastly impact the results for iGPS. High density polyethylene is the primary resin material used by iGPS in its pallet design.
CHEP based its analysis on information from the U.S. LCI Database, which was developed by the National Renewable Energy Laboratory, a research division of the U.S. Department of Energy. The critically reviewed LCI data is consistent with a common research protocol and with international standards, according to Hannum of CHEP.
iGPS did not release the basis for its raw material and manufacturing assumptions for its 2008 analysis.
More than a Marketing Gimmick
CHEP has been conducting using LCA methodology since 1999 to quantify and reduce the environmental footprint of its products and services. Life cycle inventory results help CHEP know how to prioritize changes and improve systems from the ground up.
Herndon said, “We use life cycle inventory results for decision making purposes. We aren’t just doing it for PR purposes…The point of us doing LCIs is to design with sustainability in mind up front. It’s not something you can do well after the fact.”
One example of its strategy to use life cycle results to alter the environmental impact of its business is the expansion of its facilities network. This move reduced transportation distances, a major factor in CHEP’s overall environmental footprint. Reduce transportation distances means less energy and environmental impact required for fuel.
Beyond using a very reputable firm to conduct its analysis, CHEP had its research peer reviewed by an expert in life cycle analysis to ensure that proper methodology was used. CHEP plans to launch an updated Life Cycle Calculator to compare various scenarios in the near future.
Recycling Makes a Difference
Many companies like to tout the recyclable nature of their products. But not all recycling is created equal. You have to consider the likelihood that the product will be recycled, the energy required to break down and reuse material, any waste generated by the recycling process, etc.
When it comes to pallets, wood and corrugate are more easily recycled than plastic. Another consideration is whether a product is recycled back into the same thing, which is considered closed loop recycling, or into another product, which is called open recycling to alternative product.
Since limited-use wood pallets make fewer trips than either pooled pallet, more material is used to cover the same number of trips. Herndon said, “If you use more material, you have to dispose of more. This is true even if you are doing it in an environmentally responsible manner.” Thus, the lower trip life hurts white wood when it comes to solid waste generation by volume.
Reuse of wood or plastic material does allow for a reduction in the amount of new material needed to produce each successive generation as well as decrease in the energy used to recycle material. At the same point, there is a limit to how often both wood or plastic material can be reused.
A major advantage for wood over plastic is that it is a renewable, biodegradable resource. Herndon said that even though plastic can be reused, it can never go back into the environment. Thus, it will eventually have to be disposed of even years later if it gets made into playground equipment or other products.
If material is recycled into a different product, then there remains a higher raw material cost due to the use of more virgin material for the next generation of pallet. Although you get some credit since the material is not sent to a landfill, open recycling is not as ecologically favorable as closed loop recycling. Another thing to consider is if spent material is burnt for energy instead of recycled into another product. While there is a positive credit for energy generation, there may be a negative when it comes to emissions. This total impact all depends on the material, the emission rate, etc.
The model used by Franklin Associates for CHEP’s LCI does not factor in any impact of the toxicity and recycling impacts of Deca-bromine, the controversial fire retardant used by iGPS in its second generation pallet design. Herndon said, “I assume that would increase the emissions categories.”
Thus, it is never just as simple as saying something is recyclable. A full LCA takes all the various components into consideration.
One of the major issues in any LCA is transport distances required for each material or system approach. Transportation distances affect the use of fossil fuels, emissions and total costs. You have to look at every aspect of a life cycle. It starts with raw material import, shipping from the manufacture point to the first customer, the average distance that pallet travels under load (which tends to be the same for all), return/retrieval/repair after customer use, and the end of life cycle.
Herndon said, “With a pooling system, your biggest driver is going to be transportation because you have to put more transportation into enabling the reuse. The transportation requirements are absolutely higher for the two pooling systems.”
CHEP estimates that transportation requirements will be a little lower for the plastic pool assuming that plastic pallets may not go back to a service center every time or gets handled by a more localized pallet recycler. iGPS has touted its iDepot concept where receivers scan pallets and loads are shipped to the next user not a repair depot. However, iGPS has not released any information about how widespread that practice actually is in its current system.
Another factor in the transport part of the analysis is the weight of the pallet. Typically, whitewood and plastic are similar in weight with a pooled wood pallet being the heaviest of the three. Obviously, the heavier the pallet, the more fuel that is used to move it along every stop of the process. Weight can be difficult to measure for wood pallets because the moisture content plays a big factor in total weight. Wood pallets tend to dry over time meaning that a newly manufactured pallet might lose 10-20 or more lbs in water weight once it becomes completely dry months later.
Take Away Lesson
Some of the attached sidebars explain various aspects of LCAs as well as the specific conclusions reached by CHEP in its latest analysis. Given the fact that wood has fewer environmental impacts at manufacture than plastic and that pooled pallets are built to higher specification, thus lasting longer than limited use pallets, it is not hard to believe that a pooled wood pallet generally performs better in a LCI than other options.
At the same time, the degree of impact depends on many factors that are hard to nail down and have a lot of room for speculation. No matter what type of material or system is used, the name of the game is to increase trips, reduce unnecessary travel distances and limit the environmental impacts at manufacture.
Major Drivers for Various Life Cycle Inventory Analysis Scenarios
Pooled Plastic Pallet
Advantages: Longer life span, lighter weight than pooled wood pallet.
Negatives: Extremely high environmental impact to procure raw materials and manufacture, fossil fuel impact, solid waste issues if can’t be easily recycled.
Pooled Wood Pallet
Advantages: Source reduction – less energy to produce than plastic and easier to recycle. Middle level life span compared to plastic and wood. Uses renewable resource. Total lowest life cycle cost.
Negatives: Heaviest weight of all pallets drives higher transport and fuel impacts.
Non-Pooled Wood Pallet
Advantages: Lowest environmental impact at the point of manufacture. Uses renewable resource. Is lighter than a pooled wood pallet and similar or lighter than plastic pallets. Easy to recycle compared to plastic. Less fuel used in system retrieval compared to pooled pallets.
Negatives: Has a limited number of uses compared to both pooled pallets. Potential for higher solid waste generation given the greater amount of material needed to meet the same number of trips for either pooled pallets.