The Global Alliance for Incinerator Alternatives (GAIA) recently released a report titled, “Chemical Recycling: Status, Sustainability, and Environmental Impacts.” In this report, authors Andrew Neil Rollinson and Jumoke Oladejo make a number of assertions regarding the viability of chemical recycling as a means to help address the current plastic waste crisis. Specifically, they target pyrolysis and gasification as prime examples of technologies that are being promoted for the sole purpose of enabling large plastics producers to continue business as usual while offering no benefit and, in fact, creating an array of liabilities.

For several chemical recycling companies, their conclusions are not accurate nor is their implied intent.

Although there have been responses from ACC and others in the form of letters or blogs, at Nexus we felt it was important to address the claims and their conclusions directly, scientifically, technically, and operationally with current facts and data — in a bit more depth.

The GAIA report was accurate in terms of drawing attention to the many challenges the chemical recycling industry faces and pointing out the need to find solutions. Our goal here is to better educate all stakeholders who have an interest in successfully handling waste plastics and, where appropriate, recognize opportunities for improvement.

Ending single-use plastics

To begin, several points and arguments the authors make in this report are indeed valid. They argue that the only way we can move toward long-term sustainability is to ban single-use and “unnecessary” plastics. It is truly difficult to argue with the idea that much of the plastic pollution in the global environment today arises from single-use applications. Ending all use of these plastics, however, is just not that simple.

Globally, single-use plastics serve innumerable needs: They enable hospitals to keep infections at bay and allow food to be harvested, stored, transported, and consumed safely and with vastly less spoilage and waste. Use of plastic versus the alternatives raises the standard of living for so many around the world both economically and through improved hygiene. Everyone agrees that the environmental damage that comes from the proliferation of single-use plastics must be dramatically reduced or eliminated. However, the trade-offs must be fully understood, and it is a very complex issue.

Chemical (molecular) recycling capabilities

The report authors go on to say that “… along with a lack of independent evidence on the technology, inadequate reporting … on the status of chemical recycling appears to have led to it being portrayed above and well beyond its capabilities.” Again, experience has shown this is in fact the case in many instances where so many have boldly announced new, revolutionary plastic conversion processes that disappear or rapidly fade into oblivion for a number of reasons, mostly economic. In some cases, plastic conversion facilities have even been built and operated for short periods before shuttering their doors, which prompted the authors to state that “chemical recycling should be treated with extreme caution by investors, decision-makers, and regulators,” lest they become prey to those peddling this technology like a cure-all snake oil. We completely agree and PlasticsToday recently published an article, Tough Questions — and Honest Answers — about Molecular Plastics Recycling, with questions and detailed answers to address this specific concern — questions that touch directly on legitimately understanding these technologies and their business requirements.

So, in some respects, one must completely agree with the authors in their assertion that as a society, single-use and unnecessary plastics, like those often found in product packaging, should be phased out wherever possible. One can also not refute the authors’ claims that a great deal of money and hope have been staked on individuals and companies that are more interested in making a quick dollar rather than solving a real problem.

The issue here, however, goes deeper. Simply put, good ideas and the hype around them are cheap; good implementation is not. The business of converting plastics to useful forms of recycled feedstocks has suffered from poor execution for many years, which has contributed immensely to the industry’s poor track record.

But it is here that my agreement with the authors ends. Let’s look at the report’s conclusions a bit more closely with an eye on the scientific, technical, and operational facts.

Abandon or advance?

Finding #1: Chemical recycling (both thermolysis and solvent-based) is not at present and is unlikely to be in the next 10 years an effective form of plastic waste management. With the need to dramatically reduce global fossil fuel consumption, chemical recycling appears, in fact, to represent a dangerous distraction for a society that must transition to a sustainable future.

There is a popular Chinese proverb: “The best time to plant a tree was 20 years ago. The second-best time is now.” This same philosophy can be applied to plastic conversion technologies. While it would have been great to have begun the process of developing ways to effectively and economically deconstruct, depolymerize, and recover waste plastic decades ago with the knowledge that the world would someday need it, that simply did not happen. As cited by the authors in the current and other similar reports they have written, efforts to convert plastic to various chemicals did take place as early as the 1970s. These projects (undertaken in Europe and Japan) never gained much traction owing to the low price of oil and the expense of the prototype systems constructed at the time. The science was sound; the technology/operations simply were not economical.

The technology languished outside small laboratory and backyard novelty experiments until oil prices spiked in the late 2000s. Suddenly, it potentially made economic sense to take a closer look at creating fuel/feedstock from waste plastic, but a lot of development time had already been lost. The specter of climate change was just beginning to show itself and vehicle electrification was still years away. Oil was being consumed at a voracious pace, plastic was plentiful and cheap, and over a short period of time, a number of commercial efforts were launched to reduce the amount of plastic waste in the environment but also to make some of what was then very precious oil. Unfortunately, most of these efforts failed.

Is chemical recycling now ready to make a significant impact on reducing waste plastics in the environment? The problem has grown so large that it will take much more than any single technology, administrative mandate, or isolated effort to move the needle. However, it is a step in the right direction, and given the strong desire of all affected stakeholders to support and develop ongoing and future chemical recycling efforts, there is no doubt that with concerted innovation and support, it could have a meaningful, global impact over the next decade.

Converting used, waste plastic into a useful product is no more a distraction for a society working toward a more sustainable future than was the invention of the wheel for people seeking a better, more efficient way to get from place to place. Innovation means change, and change — good or bad — is always met with anxiety and resistance. Moving any science or technology forward takes time, money, and a great deal of effort and commitment. The initiative should, indeed, be held economically accountable. But to expect chemical recycling as a technology to jump into existence and immediately be a mature industry is simply not realistic. As with any nascent technology, it will take time, but advances that merit notice are being made, every day.

Response summary: Innovation takes time to develop and mature. However, positive progress has been and continues to be made by some companies, including Nexus, that are currently providing commercial quantities of plastic pyrolysis products to companies like Royal Dutch Shell and others. This is a fact. Is work needed to scale more rapidly? Of course. Is it on track to be viable now, let alone in 10 years? Yes, it is firmly on that path today. Abandoning the path now is not the answer.

Fact or fiction?

Finding #2: Multiple pathways to adverse environmental impact exist and these are grossly under-assessed. Managing these impacts will impose high costs and operational constraints on technology operators. For this reason, chemical recycling should be treated with extreme caution by investors, decision-makers, and regulators.

With this finding, the authors appear to be saying that there are challenges in managing an array of environmentally deleterious impacts, including greenhouse-gas emissions, and that these effects have not been fully assessed and will cost money. Consequently, investors and other stakeholders should steer clear. The report cites heavy metals, polynuclear aromatic hydrocarbons (PAH), chlorine, bromine, and dioxin as the main culprits that contaminate the gas, liquids, and solid by-products produced during plastic pyrolysis. There is little doubt that the multiple studies cited in the report indeed came to some of these conclusions. However, if one digs a little deeper and reads the citations, there is a realization that many of the studies were done with municipal solid waste (MSW) and printed circuit boards, and actually came from gasification studies, not pyrolysis. Gasification systems work differently than many pyrolysis units and produce different products. In addition, many of the cited studies were done with high-temperature “fast pyrolysis” (often fluidized bed) systems that behave differently than the pyrolysis systems performing at scale today.

Municipal solid waste is a witch’s brew loaded with bleach, ammonia, and other household cleaning chemicals that find their way into pyrolysis and gasification end products. Likewise, some of the cited studies looked at automotive shredder residue (ASR), which has been proven time and time again to be wholly unsuited for product recovery through pyrolysis owing to the huge amounts of hazardous chemicals found in this refuse stream. It should also be no surprise to find heavy metals in system residues after processing printed circuit boards since they are “printed” with these metals.

On the topic of dioxins, where do they come from? Dioxins form under certain conditions and only in the presence of specific concentrations of certain chemicals like chlorine and oxygen. This most notably occurs during the process of incineration where there is plenty of oxygen present and the temperature regimes are suitable at some locations in the incinerator for one or more dioxins to form. Again, pyrolysis is not incineration. Further, there are about 75 different forms of dioxin, only several of which are considered hazardous. US EPA has reported that since the use of PCB oils was banned several decades ago, the largest source of dioxin in the environment is backyard burning (i.e., incineration) of household trash.

Pyrolysis involves heating materials in the absence of oxygen, which does not promote dioxin formation within a pyrolytic system. Research has shown that when oxygenated molecules, such as those found in polyethylene terephthalate (PET), are present within a pyrolysis reactor along with organic and free chlorine at lower temperature ranges, dioxins can form. Stoichiometry of the reactants determines the amount of dioxin created but, in general, it is extremely low. Scores of samples generated through the Nexus commercial plastic pyrolysis system have never indicated the presence of dioxin at detectable limits. One of the citations made in the GAIA report was misleading on this point; it indicated the cited study looked at plastic pyrolysis. In fact, it was a study done in 2014 by D. Chen, L. Yin, H. Wang, and P. He titled, “Pyrolysis technologies for municipal solid waste: A review.” While municipal solid waste (MSW) certainly contains plastic, MSW and plastic are quite different in behavior within a pyrolysis environment. Plastics depolymerize or “crack” into smaller polymers or even monomers, which condense into a variety of hydrocarbon products, while MSW breaks down and re-configures into a variety of chemical compounds, some of which can be very toxic. It is a simple matter of “garbage in; [different] garbage out.”

Response summary: We agree MSW is not a good feedstock for chemical recycling. Those claiming the ability to process “bobbleheads to Barbie dolls” or #3 to #7 plastics risk significant contamination issues that exert a negative impact on product output quality, quantity, and ultimately system economics. They also confuse the issue. “Wish-cycling” (attempting to recycle anything to meet consumer sentiment) is not a strategy. We would all like to address 100% of the planet’s waste plastics but saying it does not make it so. However, there is plenty of suitable waste plastics that can be recycled without the need to falsely inflate the potential by adding MSW to the equation. Therefore, it is equally important to report research findings correctly and objectively.

Finding #2a: Toxic air emissions and contribution to greenhouse gases is also called out in the report as just being part of the plastic pyrolysis technology. This is linked to the question of energy balance, which is discussed under the third finding.

This claim is simply not true. While there are numerous life-cycle analyses that have been conducted on chemical recycling systems, one of the more recent and notable ones is titled, “Chemical recycling and its CO₂ reduction potential,” published by CE Delft in 2019. CE Delft is a non-profit independent research consultancy based in Delft, Netherlands.

The report documented a detailed life-cycle analysis around various chemical-recycling approaches, including solvolysis, gasification, and pyrolysis. The report yielded several conclusions, including the estimate that widespread adoption of chemical recycling in the Netherlands would reduce greenhouse-gas emissions by about 300,000 tons per year. Researchers on this project also found that by avoiding the production of virgin materials, depolymerization saves 1.5 tons of CO₂ per metric ton of plastic recycled. By comparison, mechanical recycling saves 2.3 tons of CO₂ per metric ton of plastic recycled.

Another oft-cited report from Argonne National Laboratory determined that using pyrolysis to convert non-recycled plastics into ultra-low-sulfur diesel (ULSD) fuel results in significant energy and environmental benefits. These include up to a 14% reduction in greenhouse-gas emissions compared with the production of diesel using conventional methods. This report does not take into account the carbon-emission reductions associated with chemical recycling, as opposed to using the pyrolysis product as a combustible fuel, but still points to the fact that plastic pyrolysis can offer substantial benefits over conventional oil-refining technologies.

Both reports state that chemical recycling has a net positive impact when it comes to reducing greenhouse-gas emissions as compared to producing the same quantities via conventional pathways. Chemical recycling even offers the added advantage of retaining a majority of the carbon that makes up the various plastic polymers in the end-products, making them available without further “environmental investment” for the down-stream formulation of new end products.

In most pyrolysis systems, a portion of the input plastic is converted to non-condensable gases that are collected and used to provide all or some of the heat required to drive the pyrolysis process. This carbon is, in fact, lost to the atmosphere as carbon dioxide and generally makes up from 7% to 10% of the incoming feedstock. This contrasts dramatically with two studies cited in the GAIA report stating that over 53% of the carbon from the plastic can be lost during “upgrading” processes. The German study citing the drastic loss of carbon was “based on gasification of waste and lignite with subsequent synthesis gas conversion to methanol and olefins.” This is inaccurate because this finding relates solely to altering the input syngas to high-grade fuels through hydrogenation and does not relate to pyrolysis of plastic waste. In contrast to the gasification model, Nexus’ outputs (oil and wax) are not upgraded in any way but, instead, are sent directly to our clients and converted into plastic precursors, thus eliminating this alleged negative consequence. (Note: The second study cited, also in German, was a historical survey of gasification and pyrolysis efforts from 1973 to 2019 and did not mention anything about the purported loss of carbon.

Response summary #2a: Chemical recycling offers documented benefits as compared to other processing approaches related to greenhouse-gas emissions. Care must be taken when supporting an argument that the document citations are properly summarized or the results risk treating pyrolysis as a significant contributor to greenhouse gas emissions when, in fact, it is not.

Will it ever make money?

Finding #3: Chemical recycling is energy-intensive and has multiple intrinsic and ancillary energy demands that render it unsuitable for consideration as a sustainable technology. No chemical recycling technology can currently offer a net-positive energy balance, and there is no evidence to predict that this can improve in the foreseeable future.

Based strictly on the enterprises and efforts surveyed by the authors of the GAIA report, this finding may appear correct and implies these purported inefficiencies translate across the board to economic folly. Unfortunately for the reader, the report does not describe all ongoing programs in the chemical/molecular recycling space, making the statement simply not true. To arrive at their finding, the authors frequently conflate gasification with pyrolysis and municipal solid waste with plastic, taking findings related to one area and applying them to another. Specifically, they point to gasification and the many laboratories and even pilot-scale projects that have proven to be uneconomical and never moved from bench or pilot scale to commercial scale. But this is simply not the case for some of the current chemical recycling operations.

Economic viability requires more than a technology, more than a chemical/mechanical solution. It requires a business. While the technology is where it starts, bringing chemical recycling to life and having it become a sustainable, profitable enterprise requires a whole business support structure comprised of engineering, feedstock procurement, off-take agreements, logistics, regulatory compliance, staff training, software solutions, and more. In short, it requires the ability on the part of the technology developers not only to foster growth and development of the technology solution but to possess the requisite skills to operate a real business. At the end of the day, if recycling is not profitable for all involved without subsidies, it will very likely fail.

From the technology standpoint, economic viability is derived from operational and execution efficiency. For any technology to have a chance at success, it must be able to convert incoming feedstock into the desired output very efficiently. To do this, energy and specifically heat, entering the system must be managed and controlled in such a way that the plastic being targeted for conversion absorbs as much heat as possible while at the same time not absorbing so much to where it will break down into char. This is where the art and science of plastic pyrolysis meet, and this simple process is very hard to do. However, it is the single most important factor in determining whether the process will operate efficiently and, therefore, economically. It is precisely where a net positive energy balance is achieved.

A key concept in understanding how plastic can efficiently be converted to high-value products lies in the fact that the pyrolysis process is not doing anything other than cutting the long polymer chains that make up the plastic material. The process is not transforming one element into another — it is not alchemy — but is simply applying controlled amounts of energy to rearrange the structure of a clean, high-energy product (plastic) that already exists. Does the plastic as a polymer contain more energy than it does when it is broken down into smaller-chain molecules? Absolutely, but to make those molecules available for other uses, they must be in another form and the amount of energy required to break the plastic’s polymer bonds is far less than the energy residing in the liquid and wax products that result from an efficient pyrolysis process. The energy that goes into making a tasty chocolate chip cookie is far more than the energy required to break that cookie into hundreds of crumbs (the Second Law of Thermodynamics).

This is also why it is so critical to keep contamination levels low. Whether it is moisture, glues, inks, organics (e.g., paper, chicken bones) or even metals, these all contribute to reducing valuable product output. In addition, any material that is not plastic that enters the system absorbs energy being put into the process but gives nothing back, which reduces overall process efficiency and the goal of simply converting waste plastics into a useful hydrocarbon. An added issue is that char will always be produced and there is no system that will get it to zero. It is both the amount of char produced and how it is handled that differentiates systems and allows for the efficiencies that contribute to economic viability. This is not a trivial issue and must be fully understood when making generalized statements about a technology’s potential.

Plastic that has been created using oil and natural gas is an available, valuable resource that already has accounted for the “sunk cost” of its whole creation process, from the extraction of a fossil resource to its transport and purification. We cannot get that energy back, but by reforming the finished product — the plastic — into a new resource that displaces the need to extract additional oil or natural gas, chemical recycling effectively reduces all the energy-intensive and carbon-releasing steps that are required to make new plastic in the first place. Even better, waste plastics can be molecularly recycled in an infinite circular loop — from molecule to plastic, to waste plastic, back to the molecule, and once again virgin plastic. In contrast, paper can only be recycled five to seven times before the fibers become too short to be of use.   

Therefore, in theory, because of this molecular cycle, all plastics currently above ground would satisfy a significant amount of current and near-term plastic needs without having the negative environmental impact of extracting the oil and gas necessary to make new plastics nor the downstream impact of landfilling the waste.

While energy efficiency and positive economics are essential elements in creating technical viability, execution to accomplish these goals is equally critical. There is no shortage of good ideas and novel ways to approach chemical recycling, but there is a large disconnect between ideas and commercially scaling them. Understanding and having experience with the full spectrum of skills from construction to maintenance to procurement to environmental permitting to strategy requires a team of people with experience and knowledge in all these areas. There is an abundance of announcements around chemical recycling about what may be done in the future, but it is often the case that once the realities of commercialization set in, they flounder. The resultant impact leads to a justifiable lack of potential stakeholder trust in the space, and everyone’s reputation is tarnished.

We have worked diligently to overcome these hurdles over our 30-year history. For starters, the GAIA report points out the importance of evaluating technologies on the basis of their energy return over the amount of energy invested (EROEI), citing it as one of the most critical evaluation parameters. We agree. The Nexus plastic pyrolysis system at both the pilot and commercial scale has been third-party verified to operate with an EROEI of 18 to 35, and we continue to operate at these levels. This means the energy content of the pyrolysis oil delivered from the Nexus system is many times greater than the energy required to extract it and includes all the intrinsic and ancillary energy inputs to the system once the plastic feedstock is on site. This is an economic requirement for any system whether it is delivered to a processing plant or a landfill.

Like many other chemical recycling companies, our products are not used in fuel applications and, therefore, the energy found in the liquid products is not “liberated” when combusted as a fuel product. Instead, the products are used to make new chemicals and plastic precursors, sequestering the carbon and preventing its release into the environment. Far from being unsuitable for consideration as a sustainable technology, as stated in the GAIA report, the systems operates consistently at a level that economically produces high-quality oil and wax feedstocks, which, in turn, are used to create new chemicals and plastics from formerly landfill-bound, or worse, ocean-bound waste.

Response summary: Chemical recycling, like other conversion technologies, is energy-intensive, but if done efficiently, it can provide returns that are multiples of the energy input. Efficient and economic conversion of plastic into high-quality oil and wax on a commercial scale is taking place today within a sustainable business model.

Overblown or overlooked?

Finding #4: Grossly inadequate reporting exists on the status of chemical recycling, which, along with a lack of independent evidence on the technology, appears to have led to it being portrayed above and well beyond its capabilities. Much greater transparency on operational performance, energy balances, and environmental impact assessment must be provided as standard.

There is no question that rigorous scientific scrutiny has not been broadly applied when it comes to feedstock recycling of plastic waste. However, it is not only scientific scrutiny that has been lacking but also commercial scrutiny. Free-market economics determines success and failure with dispassionate efficiency.

The GAIA report authors warn that investors should be wary of claims made by chemical recycling companies, and rightfully so. The industry has a history of investments made in what appeared to be promising businesses buoyed by the market’s interest in finding a solution — any solution — to address the scourge of plastic litter and ocean pollution (sometimes simply to appease consumers’ desires to feel less guilt for using plastics). To that end, little concern sometimes is put toward implementing necessary business practices, such as conducting proper due diligence or obtaining third-party validation of the claims being made. The result has been numerous false claims and failures in this space that would have been avoidable if the business had been objectively assessed, not only from a technology standpoint but also from a business perspective.

The net result of these failures has created a cautionary tale for investors and other stakeholders that survey the chemical recycling landscape but which, in turn, is slowly leading to better-informed decisions being made on whether or not a given technology or business can actually succeed and be sustainable. You can have the greatest technology in the world, but if it does not make money, it will not be functioning very long.

There are, of course, different reasons for investing in chemical recycling. The insatiable appetite for recycled products, whether from mechanical recycling (e.g., PET) or from chemical recycling, in some cases has allowed investments to be made in marginal business ventures if there is even a chance that these firms can help fulfill some of the sustainability needs of the investing parties. The movement to reduce plastic pollution in the world’s oceans and rivers has motivated many organizations to back technically unsound ventures in the hopes there can be some positive progress in these areas. The desire is strong to do something, anything to improve the world’s environment and to help move toward a more sustainable society.

Unfortunately, without transparency on operational performance, energy balances, and environmental impact, these well-meaning efforts tend to fizzle and fade, often sinking along with investors’ money. As a result, conclusions such as those made in the GAIA report are the result and are inevitably damning and misleading. But we should not “throw out the champagne with the cork.”

Grants and subsidies also can temporarily conceal fundamental business problems. They can play an important role initially, but unless a trajectory to profitability within a free market environment is clear before they expire, the odds are not good for a specific technology’s or company’s survival. Marketing hype can only be maintained for so long before the curtain is pulled back and harsh reality comes calling. The importance of solving the plastics waste problem is too great to leave to hype. It is why we agree directionally with GAIA on the importance of properly assessing these solutions, but disagree that none exist, as we have worked hard to prove otherwise

Response summary: The chemical recycling industry will benefit as the objective and transparent evaluation is applied both to the technologies and business models. It is essential to establishing the industry’s credibility that companies have a sound scientific and business model before soliciting investors’ dollars and making unsubstantiated claims. The failures of the few should not be imposed on the industry. Imposters may surface, but there are real players with real results today that merit attention and consideration.

Summary

Chemical recycling by itself is not the sole answer to the world’s waste plastic problem, but it can certainly be part of the answer. The GAIA report merits attention, not because it concludes that chemical recycling is not viable, but because it points out the need to hold all players in this space to a higher standard of proof — scientifically, technically, and operationally.

There is no argument from anyone that plastic waste and the litter that it spawns is a blight on the planet. Plastics have allowed people to attain a higher standard of living, endure less disease, and live longer lives through increased sanitation, lower costs, and energy efficiency. The consequences of consuming these plastics and current “end-of-life” solutions, however, are not sustainable.

While it is not realistic to believe that all plastics will be phased out of existence (owing to the benefits they provide), it is realistic to work toward the dramatic reduction of many single-use plastics, particularly in packaging. Thin-film plastics allow food to be transported, stored, and consumed without spoiling, and society’s confrontation with the COVID-19 virus has brought home the stark reality that we literally cannot live without the many forms of single-use plastic, particularly in healthcare settings.

But the problem is not just “bad” plastics. It is true that plastics manufacturers need to work toward making plastics more recyclable so that the chances of it being returned for reuse improve, and for all levels of government to improve access to recycling options. However, the core issue also lies with people, since it is ultimately people, humans, that determine where the plastic they use ends up.

The idea that most of the carbon held in processed plastic is lost in this process is simply untrue. The products of chemical recycling are not just burned, since that defeats the purpose, but instead can be used in new products that keep carbon from entering the atmosphere and avoid the environmental impacts that accompany the creation of new plastic from fossil sources.

Businesses like Nexus exist today, efficiently and economically converting many of the plastics that do not have beneficial reuse, repurpose, or mechanical recycling outlets. But instead of landfilling, these plastics can be converted into useful new chemicals and virgin plastics.

GAIA has concluded chemical/molecular recycling is not an option. We respectfully disagree based on the facts that include proper interpretation of past research and the scientific, technical, operational, and economic scrutiny of existing — not promised — solutions today that chemical recycling should continue to be pursued, invested in, and objectively evaluated. Then, perhaps re-starting this discussion a few years from now, the trees planted today will have flourished enough to address the plastic waste problem we all seek to solve for the benefit of billions of people worldwide. Is chemical recycling doomed and just a “dead-end technology” as proclaimed by GAIA Science and Policy Director Neil Tangri? Thankfully, for the sake of our precious planet, the answer is a resounding, “No.”