Are Plants the Solution to our Plastics Problem?
Plastic made with inexpensive feedstock, supported by large investment in infrastructure dominated by oil and gas companies, appears not only to be here to stay, but poised for production growth. At the same time, media and social pressure to do something about plastic waste is increasing. Recycling is one solution, but the underlying question persists: is there a more environmentally attractive replacement?
Fossil fuel-based chemicals, largely ethylene and propylene, are used in 99% of plastics production. Many of the largest oil and gas companies own, operate, or are investing in plastics infrastructure as plastics are part of the fossil fuels supply chain. In the US, at the end of 2017, $164 billion was planned for 264 new or expanded fossil fuel-based plastics infrastructure and global production of critical plastics feedstocks is expected to grow by 33% between 2015 and 2025.
Are there bio-based alternatives? Do they have any hope of replacing fossil fuel-based plastic in the next 20 years?
Potential replacements
The cheapest and most common type of bioplastic is polylactic acid (PLA), which is used largely in food packaging as a replacement for polystyrene (PS), polypropylene (PP) and acrylonitrile butadiene styrene (ABS). Production capacity for PLA is expected to grow 60% by 2023 compared to 2018. Polyhydroxyalkanoate (PHA) is an emerging bioplastic with more desirable qualities than PLA, as it is biodegradable and has a wider array of physical and mechanical properties.
Driven by consumer demand for alternative plastics materials, the global bioplastics market is projected to increase from less than 2% of the total plastics industry in 2015 to 40% of the total plastics industry in 2030. Bioplastics are seen as an easy and attractive way for companies to reach their sustainability goals, as they can be used with existing injection molding equipment. Some high-profile corporations, such as Starbucks and Coca-Cola, have recently launched initiatives to source bio-plastic materials for cups and bottles.
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Challenges and opportunities for innovation
Although bioplastics are considered a promising alternative for fossil fuel-based plastics, the current technology landscape must overcome significant challenges to solve the environmental problems connected to conventional plastic. Some key challenges of bioplastics are feedstocks, sophistication of materials and applications, as well as disposal after use.
Currently, most bioplastics use sugar or starch from corn as feedstock. Although these feedstocks are renewable, they divert land and resources from food production in an increasingly food-scarce world. A potential solution for this is the use of waste as feedstock. Genecis and TerraVerdae Bioworks are examples of innovative startups that have taken this approach, using organic waste (food and agriculture) and waste methane and methanol, respectively, as feedstock for bioplastics.
After use, bioplastics are either sent to landfills, enter the recycling stream along with conventional plastics, or are sent to industrial compost facilities. Approximately 57% of bioplastics produced in 2018 were not biodegradable (i.e. PET, PA, and PE). Although these materials are made from plant-based, renewable sources, they act similarly to fossil-based plastics in marine environments, breaking down into microplastics and causing problems when ingested by animals. Even biodegradable plastics do not generally decompose within a reasonable period and thus require industrial composting. Bioplastics, particularly biodegradable plastics, can cause complications in recycling streams when they are recycled rather than composted, and contamination of a recycling stream will result in the materials being landfilled.
More applications, better quality
For bioplastics to be a comprehensive replacement for conventional plastics, they must be viable in a broad range of applications and meet established quality standards. Ecovative is one example of a startup seeking to expand end-use applications of bioplastics, using mycelium as feedstock to create materials with a broad range of high-performance applications, including footwear and leather. The mycelium-based materials offer an alternative for styrene, the polymer used to make Styrofoam, which is typically landfilled due to recycling limitations. In addition, Ecovative’s products are home-compostable, which is a potential solution for after-use issues with bioplastics. Genecis and Bioextrax produce PHA, a high-quality bioplastic that is biodegradable and has a wide range of sophisticated applications. In the past, PHA has been costly to produce, but these companies have developed innovative processes to produce PHA at a lower cost.
Typically, bioplastics have only been economically viable when fossil fuel prices are high. There appears to be some willingness by corporations to pay a premium for bioplastics to meet consumer demand and reach sustainability goals. Technological innovation will drive bioplastic prices down even further and increase their viability across a wider range of applications. Bioplastics do offer an alternative but are currently not advanced enough to offset the established supply chain and lower cost of fossil fuel-based feedstocks.
