Authors: Laura Äkräs and Marjatta Vahvaselkä
No alternative is perfect, yet advantageous in the right context
You already know this, but let’s recapitulate! Nowadays, the role of biomass-derived, bio-based feedstock has increased as a raw material for a myriad of end applications as one approach to reduce some of the negative environmental impacts caused by fossil-derived products. This can be seen, e.g., in the form of increased legislation as well as an urge to develop and commercialize new bio-based products and novel or improved clean technologies to foster the more sustainable production, consumption, and finally disposal.
- Which bio-based feedstock types should be selected, for instance, to produce plastics?
- How different alternatives could be compared?
- And yet, which factors effect on the decision-making when evaluating, comparing, and finally selecting feedstock alternatives for specific purposes?
Here, we try to answer these questions by taking a dive into the multifaceted sustainability of bio-based feedstock to produce plastics, with a specific focus on plant-based oils. So, which factors take it all?
Collaboration – it’s always worth it
For starters, we as researchers in the Work Packages 1 and 4 (WP1 and WP4) within the project ValueBioMat have constructed a Multi-Criteria Decision-Making (MCDM) framework to analyze and evaluate various plant-based oil options to produce bio-based plastics. In our opinion, MCDM turned out to be a useful tool for this purpose and, through massive background research and data collection step (by utilizing various databanks and scientific literature), a solid, broad, and extensive understanding about the plant-based oils under analysis was gained. Here, our aim is to open this gained knowledge and highlight some of the remarks made during the research (noteworthy, the original manuscript is currently under review in a scientific journal). Let’s dive in!
Wow – look at this multifaceted data!
First, one could think that it’s easy to select the most sustainable plant-based oil. It is far from it! While evaluating different plant-based oil alternatives, we identified multiple criteria with even contradictory effect on the performance of these oils. On one hand, some plant-based oils may be substantially environmentally friendly, but simultaneously possess, i.e., low production quantities and moderately high prices (e.g., linseed oil). On the other hand, some oils may have a unique chemical composition, which is superior and therefore widely used for certain end applications, but possess high environmental impacts (e.g., castor oil). Some of them may be widely available with a reasonably high production quantities and adequately low prices, but severely compete with food production (e.g., rapeseed and sunflower oil), or have rather high environmental impacts despite their availability (e.g., soybean oil produced in South America). Which one to select?
In short, there is no one right answer! This is since no plant-based oil is perfect or completely sustainable – they have their own advantages and disadvantages, which need to be evaluated within the context they’re planned to be used to find out their level of sustainability and ‘suitability’ for a specific purpose. Overall, though, understanding of the environmental impacts caused by different feedstock types, such as plant-based oils, considered for various end applications, is of utmost importance.
These data gaps – just another piece of cake?
While conducting the research, we observed that, in general, information is well available regarding various plant-based oil alternatives. Nonetheless, the existing databanks (and to some extent scientific literature) do not contain an adequate amount of information regarding the plants of jatropha (Jatropha curcas) and vernonia (Vernonia galamensis). This is slightly surprising due to the many potential features of these plants, such as their ability to be cultivated on marginal lands, together with their rather high oil content, and good chemical functionality. Consequently, before the potential of jatropha and vernonia can fully be exploited, for example for the life cycle assessment (LCA) calculations or MCDM analysis, the information regarding them needs to substantially be increased and made publicly available to everyone.
Next steps – what did we learn?
As the greatest to find, castor oil was found out to be the most utilized building block in the available commercial plastics, particularly in polyamides, simultaneously possessing (due to the cultivation and oil extraction stages of castor from India) rather high environmental impacts. In addition to this, castor oil possesses low production quantities and high price, but contains unique ricinoleic acid, which is highly suitable for the purposes of the chemical industry. Stemming from these findings, within the project ValueBioMat, the next step of the collaborative work of WP1 and WP4 is to focus on in-depth assessment of the environmental impacts of the selected castor oil-derived polyamide over its whole life cycle from cradle-to-grave. This will include stages of cultivation and harvesting, oil extraction, manufacture of polyamide, 3D printing, and end-of-life options, to identify the environmental hotspots as well as environmental burdens within the system under analysis.