Sustainable aviation fuel (SAF) is anticipated to have a significant impact on decarbonizing the aviation industry owing to its ability to be seamlessly incorporated into the current aviation infrastructure. This paper analyzes the potential of meeting the proposed SAF targets set by the ReFuelEU initiative. The approved SAF production pathways according to ASTM D7566 using renewable bio-based feedstocks were defined and analyzed. Moreover, a detailed matrix for comparison was used to provide an overview of the current state of those pathways. The analysis has shown that hydroprocessed esters of fatty acids (HEFA), alcohol to jet (ATJ), and Fischer–Tropsch (FT-SPK) are the most promising pathways in the foreseeable future due to their high technology readiness and fuel levels. HEFA is the most mature and affordable pathway; therefore, it is expected to form the backbone of the industry and stimulate the market in the short term despite its low sustainability credentials, limited feedstock, and geopolitical implications. On the other hand, FT-SPK can utilize various feedstocks and has the lowest greenhouse gas emissions with around 7.7 to 12.2 gCO₂e/MJ compared to the conventional jet fuel baseline of 89 gCO₂e/MJ. Overall, the EU has enough sustainable feedstocks to meet the short-term SAF targets using the current technologies. In the long term, the reliability and availability of biomass feedstocks are expected to diminish, leading to a projected deficit of 1.35 Mt in SAF production from bio-based feedstocks. Consequently, a further policy framework is needed to divert more biomass from other sectors toward SAF production. Moreover, a significant investment in R&D is necessary to improve process efficiencies and push new technologies such as power-to-liquid toward commercial operation.

Two of the most commonly used solid biomass sources for fuel are wood chips and wood pellets. The calorific value and the moisture content of those biofuels determine the efficiency of the CHP and the biorefinery plants. Therefore, with the increased shift towards a biobased economy, the biomass cost and its physical properties must be precisely determined. Most of the current standards are lacking and provide neither enough details about the issues caused by the biomass heterogeneity nor with the variation in experimental practice. Phenomena such as data scattering, poor repeatability and wide uncertainty, are mostly observed during the measurements of the calorific value and the moisture content. To overcome such issues, an interlaboratory comparison between three national metrology institutes using bomb calorimetry has taken place. The comparison helped to identify the root causes behind the poor reproducibility of the wood samples. Factors such as the equilibrium moisture content of the biomass, the pellet mass, the applied pressure to form the pellet, the handling techniques and the determination errors are highlighted and analyzed. The final results paved the way to provide an enhanced detailed experimental practice where the repeatability and reproducibility have been strongly improved. Moreover, the detailed uncertainty sources and calculations are presented. It has been found that by fulfilling the recommended approach the measurement repeatability improved by up to 50–80%, while the final uncertainty improved by 10–30%. This enhancement leads to a maximum relative expanded uncertainty of around ±1% (coverage factor of k = 2 and a confidence level of 95%).