| Popis: |
Biomass can play a role in the transition to a sustainable energy system. In principle all biomass can be used for make biogas. However, biogas yields differ for the various biomass types. Next to this, biomass is also used for other needs like food and feed. These competing uses affect the price of the biomass on the market. For getting insight into the potential of biogas as a future energy source it is essential to have an overview of competing uses of available biomass sources. Knowledge of the competing uses of each type of biomass is scattered throughout literature. Reviewing literature manually for this information is immensely time-consuming and limited by human reading capacity. For that reason, in this study we applied a machine learning technique to perform a large literature review to provide an extensive review of current competing valorization pathways of biogas feedstocks. To do this, we first gathered literature abstracts related to biogas feedstock valorization pathways from academic databases. The abstracts were then automatically scanned for mentions of terms contained in a list of feedstocks and a list of valorizations. The list of biogas feedstocks was taken from the European Feedstock Atlas. The list of biomass valorizations was created based on the Biomass Value Pyramid which mainly categorizes the use of biomass into four groups: Food for humans, Feed for animals, Biobased materials and Energy. To further evaluate which feedstocks were mentioned with which valorization pathways, we used a machine learning technique called cooccurrence analysis, which analyzes the significance of two terms appearing together in the same abstract, compared to how likely they would appear together just based on chance. This assisted with the process of identifying actual valorization pathways versus false positives. For further validation, for each cooccurrence of feedstocks and valorization options, we were able to trace back the abstracts mentioning that combination. The final result is a webbased visualization of a map which shows the connection of biogas feedstocks together with their all competing uses. Feedstock valorizations are colormarked in an increasing magnitude order corresponding to the increasing value of biomass. The visualization also shows the heaviness of the connection between each biomass and its different uses based on the significance of cooccurrence of them in literatures, which can be related to the commonness of the biomass use in practice. Beyond the goal of visualizing the connections between biogas substrates and their competing uses, the map provides ideas to explain phenomena in the biomass market such as prices and preferences. Lastly, this map is a reminder for biogas concerned parties to make the production plan based on practical availability rather than only technical information of the feedstocks. |
