In order for the EU to achieve its 2050 climate objectives, transport-, power-, and industry sector, which heavily relies on fossil fuels, must significantly decrease their emissions. Green hydrogen and sustainable fuels, among them e-methanol, e-kerosene, and green ammonia, produced using the Power-to-X approach, have been recognised as viable alternatives to reduce emissions and support decarbonization. However, there are some techno-economic challenges in adopting sustainable fuels, particularly related to the higher costs compared to fossil fuels. The economic feasibility of sustainable fuels depends on the cost of green hydrogen and carbon capture technology. Large-scale deployment, improvements in electrolysis modes, and intensive implementation of point-of-source CO2 capture technologies could make sustainable fuels cost-effective and competitive with fossil fuels by 2050. However, it seems improbable that e-fuels would become widely available at low cost in the near future. The prospective environmental performance of adopting e-methanol, e-kerosene, and e-ammonia is examined, highlighting the necessity of conducting a thorough investigation into the possible negative impacts on human health and ecosystems.