Blending bio-oil with fossil fuels: Opportunities for low-carbon fuel production

The global energy landscape is undergoing a significant transformation with a growing emphasis on sustainability and reduced carbon emissions. About 80% of the world's CO2 emission comes from traditional fossil fuels, making them an important contributing factor to greenhouse gas emissions. However, bio-oil, a renewable and carbon-neutral liquid fuel derived from biomass, holds the potential for reducing carbon emissions. Recent studies have shown that bio-oil blending can reduce carbon emissions by up to 30% compared to traditional fossil fuels. Hence, this review delves into the potential of blending bio-oil with fossil fuels, exploring recent advancements in catalyst design. Novel catalysts are being developed to improve the efficiency of bio-oil processing techniques like catalytic cracking and hydrothermal liquefaction. These advancements aim to enhance bio-oil properties like stability, heating value, and miscibility with fossil fuels. Research suggests that these advancements could enable bio-oil contents in blends to reach up to 50% or higher, compared to the current limitations. We also highlighted ongoing investigations to optimize bio-oil-to-fossil fuel ratios for specific applications. This optimization considers factors like engine performance, emission reduction targets (e.g. achieving a 70% reduction in CO2 emissions), economic viability, and long-term storage stability of the blends. The environmental benefits and sustainability implications of such blending strategies are also discussed, offering valuable insights into the role of bio-oils in achieving cleaner and more sustainable energy systems. This review therefore underscores the potential of bio-oil blending as a viable pathway to bridge the gap between traditional fossil fuels and a more sustainable energy future, while also outlining the research directions and challenges that warrant further investigation in this promising field.