Journal of Energy Bioscience 2024, Vol.15, No.2, 72-84 http://bioscipublisher.com/index.php/jeb 78 GHG emissions compared to conventional fossil fuels. For instance, a life cycle assessment (LCA) study conducted in Spain revealed that using rapeseed oil biodiesel (B100) instead of petroleum-based diesel could reduce GHG emissions by approximately 74% (González-García et al., 2012). Similarly, another LCA study in Denmark found that the climate change potential from the production and use of rapeseed biodiesel was significantly lower, with emissions of 57 kg CO2-eq per 1,000 km compared to 214 kg CO2-eq per 1,000 km for conventional diesel (Herrmann et al., 2013). These reductions are primarily attributed to the renewable nature of biodiesel and the carbon sequestration capabilities of rapeseed crops during their growth phase. However, it is important to note that the environmental benefits of rapeseed biodiesel are not uniform across all impact categories. While GHG emissions are reduced, other environmental impacts such as acidification, eutrophication, and photochemical smog may increase. For example, the Spanish LCA study reported increases in acidification (+59%), eutrophication (+214%), and photochemical smog (+119%) when using rapeseed biodiesel compared to conventional diesel (González-García et al., 2012). These findings highlight the need for a comprehensive environmental assessment when considering the adoption of rapeseed biodiesel. 5.4 Sustainability considerations and certification Sustainability considerations for rapeseed biodiesel encompass a range of factors, including land use, resource efficiency, and socio-economic impacts. The cultivation of rapeseed itself poses challenges, as it requires significant inputs of fertilizers and intensive agricultural practices, which can lead to environmental degradation (González-García et al., 2012). Additionally, the energy consumption in the production process, particularly during the transesterification stage, is substantial (Samani et al., 2018). To address these sustainability challenges, certification schemes and regulatory frameworks have been developed. The European Union, for example, has enacted directives requiring member states to ensure that a certain percentage of energy in transport comes from renewable sources, including biodiesel (Herrmann et al., 2013). Certification schemes such as the Roundtable on Sustainable Biomaterials (RSB) and the International Sustainability and Carbon Certification (ISCC) provide guidelines and standards for sustainable biodiesel production. These certifications consider various sustainability criteria, including GHG emissions, land use, and socio-economic impacts, to ensure that biodiesel production does not lead to adverse environmental or social outcomes. Moreover, innovative production methods are being explored to enhance the sustainability of rapeseed biodiesel. For instance, a study reported a method to produce biodiesel directly from intact rapeseeds without the need for catalysts, reducing the environmental footprint by minimizing water and solvent use (Tanner et al., 2023). Another study suggested the use of residual straw from rapeseed fields for combustion in power plants, which could further improve the carbon sequestration potential and overall sustainability of the biodiesel production process (Herrmann et al., 2013). 6 Case Studies and Global Perspectives 6.1 Successful implementations of rapeseed biodiesel production Rapeseed oil has been successfully utilized for biodiesel production in various regions, notably in Europe and Canada. In Europe, the hydroprocessing of rapeseed oil has been a significant technological advancement. This process involves the conversion of rapeseed oil into hydrocarbon-based biodiesel, which is compatible with existing diesel engines. The hydroprocessing method, which operates at temperatures between 260 ℃-340 ℃ and pressures of 7 MPa, has shown promising results with the production of high-quality biodiesel components such as C17 and C18 n-alkanes and i-alkanes (Šimáček et al., 2009). In Canada, the optimized alkaline-catalyzed transesterification of rapeseed oil has been a key method for biodiesel production. This process involves the use of methanol and potassium hydroxide as a catalyst, achieving a biodiesel yield of 95%-96% under optimal conditions. The produced biodiesel meets the stringent quality standards set by the American Standards for Testing Material (ASTM) and European EN standards, making it a viable alternative to conventional diesel (Rashid and Anwar, 2008).
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