Can bioplastics offer a sustainable future for the chemicals industry?

Last drop?

15 January 2009 00:00  [Source: ICB]

With the prospect of oil supplies eventually drying up, bioplastics offer a more sustainable future. But can they live up to the hype?

CONCERNS ABOUT future supplies of petrochemical raw materials and plastics disposal have sharpened the focus on renewable and biodegradable plastics. Many different types of bioplastics are produced today, but they are still on a journey to full sustainability. There are even claims that, in certain circumstances, traditional plastics could be environmentally preferable.

Production of bioplastics has the potential to generate less greenhouse gases and require less energy than traditional plastics, says industry association European Bioplastics. Harald Kab, chairman of the association, says bioplastics made from renewable resources have the advantage that they are compostable and, if incinerated, produce greener energy since the renewable carbon content of the raw materials is recycled back to carbon dioxide.

One of the main bioplastics is polylactic acid (PLA), which is produced from renewable resources and can be composted. It can also be chemically recycled through hydrolysis into PLA feedstock lactic acid.

JUST HOW GREEN IS IT?

Leading PLA producerNatureWorks, a 50:50 joint venture between US agricultural group Cargill and Japanese fiber and chemical maker Teijin, has been criticized by environmental groups for not promoting sustainable farming practices and for using genetically modified (GM) corn as feedstock. NatureWorks produces PLA, branded Ingeo, in Blair, Nebraska, US.

"Just because it is bio-based, that doesn't make it green," says Mark Rossi, research director at environmental group Clean Production Action. Bioplastic producers need to encourage the farming community to make their practices more sustainable by making improvements in areas such as soil conservation, pesticide use and crop rotation, he says. "Otherwise, we will end up with the same old farming practices that are environmentally degrading, to make plastics."

In fact, he suggests, relatively benign petroleum-based plastics, such as high density polyethylene (HDPE) and polypropylene (PP), with a high recycled content compare favorably with Ingeo. A 75% post-consumer recycled content PP product, containing generally benign additives, for example, is environmentally preferable to NatureWorks' corn-based PLA, he claims.

Despite the agricultural concerns, Rossi acknowledges that NatureWorks deserves credit for producing a "green chemistry" product. Lactic acid is relatively benign, and the environmental impact of NatureWorks' bio-refinery is "orders of magnitude" smaller than a petroleum refinery, he says. "If PLA production were based on sustainable agricultural practices, it would be a deep green product."

Considering the "peak oil" concept - that oil production will peak and supplies will start declining, "plant-based matter is going to be the driver for how we create our next generation of plastics," Rossi adds.

Marc Verbruggen, NatureWorks' CEO, notes that PLA production does not have to be based on corn. The company uses corn feedstock because the production facility is located in Nebraska, in the middle of the US corn belt, he says, but a second facility could be based on tapioca or sugarcane, for example. And NatureWorks expects to start producing PLA from cellulosic feedstock within the next 10 years.

Using cellulosic feedstocks avoids competition with food crops. It would also allow increased volumes of bioplastics and improve the competitiveness of PLA versus traditional plastics, Verbruggen says. "The use of cellulose is probably five to 10 years away," he states. "But clearly, that is the direction the industry is going in. At that point, I think we will become extremely cost-competitive with oil-based products."

CHOICES, CHOICES

End-of-life solutions are also central to the bioplastics debate. Like most traditional plastics, bioplastics can also be recycled and incinerated for energetic recovery. They are often also compostable.

Industrial composting, known in Europe as organic recycling, is an end-of-life option in some European countries, such as Germany, the Netherlands and Scandinavia. But there is little industrial composting infrastructure in many regions, including the US.

The US also lags Europe in terms of energetic recovery, while recycling of bioplastics is in its infancy on a global basis. Investment in the infrastructure for recycling new bioplastics is not likely to happen until there are sufficient volumes, says Kab. "Chemical recycling requires enough material in a certain region to build a recycling facility."

The technology exists at recyclers to sort PLA bottles from PET and other plastics, but you have to consider the economics of scale, Verbruggen remarks. "If you only have a couple of thousand PLA bottles among billions and billions of PET bottles, the average recycler has little interest in doing something with those PLA bottles."

Verbruggen admits that in the US most of the company's bioplastic production will end up in landfill. "We clearly expect chemical recycling and composting of bioplastics to gain importance with improving Ingeo economies of scale and overall improving economics for recycling."

While landfill is still prevalent in the US, it is not an option in most European countries, notes Kab. In Germany, for example, plastic packaging will either be composted or incinerated, he says. But the UK, like the US, has a lot of catching up to do.

NatureWorks believes that chemical recycling is preferable to composting. "We are not obliged to go the composting route," says Eamonn Tighe, NatureWorks' business development manager for the UK and Ireland. "In fact, we'd rather the product was recycled and went round the block several times before it ended up in a composting facility."

Over the next five years, the US group intends to establish a downstream end-of-life infrastructure for bioplastics. This, Verbruggen says, requires "responsible product launches" that ensure that the brand owner launches the product in cooperation with recyclers.

NatureWorks is examining recycling options in the US and Italy as part of its entry into the PLA bottle market. Ingeo water bottles are being launched by Primo Water in the US and Sant'Anna di Vinadio in Italy. Sant'Anna already has an arrangement with Belgium's Galactic, which is building a pilot plant to hydrolyze post-consumer collected PLA back into lactic acid.

Sorting the PLA bottles from the PET and other plastic bottles could become economically viable in 2009, when larger numbers of PLA bottles will enter the market, Verbruggen suggests. PLA producers could buy these bottles back, transform them into lactic acid, and then back into PLA, he says. "Then we see the real end-of-life option coming into play."

SEPARATE BUT EQUAL

There have been concerns, particularly in the UK, that PLA, which looks identical to PET, could contaminate the waste stream at recyclers. "This needs to be put in context," says Tighe. "First, bottles are not a key part of our business in the UK. Second, the systems that are in place today can separate out the different plastics, including PLA."

NatureWorks claims to be the world's largest bioplastics producer, accounting for about 80% of global capacity for bioplastics that are renewable and can be composted. The company is doubling the capacity of its PLA plant in Blair, to 140,000 tonnes/year.

US-based biosciences firm Metabolix will be the world's number-two player when its starts up production next year, according to Verbruggen. The company, through a 50:50 joint venture with US-based crop science giant Archer Daniels Midland, is building a 50,000 tonne/year plant that will produce a biodegradable plastic based on polyhydroxyalkanoates (PHA).

DuPont produces several bioplastics, which it says contain a minimum of 20% renewably sourced ingredients by weight. The company's Sorona thermoplastic polymer contains about one-third renewably sourced material derived from corn, with renewably sourced 1,3 propanediol (PDO) as a key intermediate.

Other producers range from German chemical major BASF, which makes the petrochemical-based biodegradable polyester Ecoflex, to UK-based Innovia, which produces cellulosic films, and starch-based producers including Italy's Novamont, US-based Cereplast and Australia's Plantic.

Producers will be hoping that bioplastics' green image will provide some protection against the global economic downturn. But the fall in prices for traditional plastics in recent months is not helping.

Ingeo was cost-competitive compared with polystyrene (PS) and PET five months ago, but the fall in PS and PET prices mean that is no longer the case, says Verbruggen. However, oil will ultimately run out, he remarks. "In 10 or 20 years from now, I am absolutely convinced that biopolymers will be a very cost-competitive alternative to oil-based products."

Bioplastics will be the future material of choice since they are made from a renewable source rather than from oil, he insists. "As a global society, we are already strategizing on how to preserve oil and bioplastics will be part of the solution."

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By: Anna Jagger
+44 20 8652 3214



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