Sustainable biofuel production from oleaginous crops in Kenya

Kenya is experiencing a rapid economic growth, with a population growth rate of 2% annually and an urbanization rate increasing by 3.7% per year. This has led to rising energy demand and a significant increase in CO2 emissions. The national energy mix is dominated by biomass (62.5%), petroleum products (18.5%), and renewables (16.9%). Although transport accounts for only 21.7% of final energy consumption, it is responsible for 62% of CO2 emissions and consumes 76% of petroleum products, primarily diesel and gas oil (51%). Kenya's heavy reliance on petroleum imports is striking, domestic oil production is nonexistent, and net imports cover 123.2% of final petroleum consumption. From 2000 to 2021, imports rose by 274%, accounting for 91% of the country's total energy imports. Considering these challenges, the development of alternative fuels is critical to reducing fossil fuel dependence, diversifying the energy mix, improving energy security, and lowering greenhouse gas emissions. In this context, this study aims to characterize two local oleaginous feedstocks, Croton megalocarpus oil and waste cooking oil, to assess their suitability for biodiesel production. While sustainable biofuels are key to the energy transition, it's essential to manage competition with food production and ensure the sustainable use of land and water resources. Among promising solutions, Croton megalocarpus, a native species to sub-Saharan Africa that thrives on marginal land with minimal water, offers significant potential. Similarly, urbanization and population growth are increasing the availability of waste cooking oil. Often discarded as waste, it can be collected and transformed into a valuable resource for biofuel production if an efficient infrastructure is established. To assess the potential of these feedstocks, detailed tests were conducted to characterize their chemical and physical properties using GC-MS (Gas Chromatography-Mass Spectrometry) and FTIR (Fourier Transform Infrared Spectroscopy), measuring parameters such as acidity, density, viscosity, calorific value, moisture content, saponification number, peroxide value, iodine number, and cloud point. These results were compared with those of more established feedstocks like Jatropha and Ricinus, providing insight into the feasibility of using these oils for biofuel production. Following the characterization, lab-scale experiments were carried out to explore the challenges of converting vegetable oils into biodiesel via transesterification with basic catalysts. Following lab experiments on transesterification for biodiesel production using the same oleaginous feedstock, this study also examines the theoretical requirements for producing a different class of biofuels: Lipid-based Renewable Hydrocarbons such as HVO (Hydrotreated Vegetable Oil) and HEFA (Hydroprocessed Esters and Fatty Acids). These hydrocarbons offer significant advantages over biodiesel due to their non-oxygenated nature, making them fully compatible with existing fuel infrastructure without blending constraints, while still contributing to the transition towards renewable energy sources. Overall, the study demonstrates that the sustainable utilization of local resources, such as Croton and waste cooking oil, presents a viable pathway for Kenya to reduce its energy dependence, foster a sustainable biofuel industry, and promote economic and environmental development without compromising food production or land use.