Using crop statistics (2020-21), publicly accessible data, standard procedures and literature, this study estimates the bioenergy potential of crop biomass residues in all regions of Ethiopia. The assessment considered 44 different types of residues from 30 different crops grown in Ethiopia. The country generates 69 569-105 522 kt y^-1 gross crop residue biomass, of which 42 621-72 194 kt y^-1 (or 61-68% of gross) are estimated as recoverable for bioenergy production. Amongst all the eleven regions, Oromia produces the highest amount of recoverable crop residue (45%) at region level. Cereals produce the highest recoverable crop residue (80%), followed by fruit crops (8%). Maize (36%) and sorghum (29%) are the two crops that produce the highest recoverable residue amongst all the crops. The estimated 559-1144 PJ y^-1 bioenergy potential for Ethiopia from recoverable crop residue varies by region and ranges from 0,15 to 0,37 PJ y^-1 (Afar) to 254-521 PJ y^-1 (Oromia). Decentralized energy planning using crop residues in Ethiopian regions is expected to benefit from the produced data, which will help the country's overall growth in renewable energy. Biological and thermo-chemical conversion systems that are now in various stages of demonstration, commercialization, development, and research can convert biomass into energy. Performing research and development, establishing a database for local biomass resources, and developing a unified bioenergy unit and policy with all stakeholder's participation and engagement are all critical aspects of Ethiopia's sustainable bioenergy sector. Furthermore, value chain analysis of biomass feedstock, capacity building and awareness creation, and decentralized models development are all important for the country's bioenergy development.

Despite the age of the technology, sub-Saharan African (SSA) countries have numerous challenges that hinder biogas from being widely adopted. This review investigates the current gap between holistic use and the need for small-scale household biodigester adoption and effectiveness in rural and semiurban households of SSA. It reviews the present situation and potential of small-scale household digesters for sustainable future energy and biofertilizer use, with a focus on SSA. A literature survey was performed on small-scale household biogas digesters, and issues relating to the distribution, use, and implementation status with their implications on the future of small-scale household digesters in SSA were briefly reviewed. In recent years, the overall number of domestic biogas digesters installed across SSA countries has shown a significant increase due to the efforts of the National Domestic Biogas Programs such as the African Biogas Partnership Program with the Netherlands Development Organization and the Humanist Institute for Development Cooperation. However, based on an extensive literature review on small-scale household biodigesters in SSA, the study highlights that the success of biogas technology as a clean domestic cooking fuel has been relatively low. The findings of this review show that SSA countries still face a number of hurdles, the most significant of which can be boiled down to the need for technological advancement according to local context, social acceptance, and large initial investment costs. In order to overcome these obstacles and advance technological capability, social acceptance, financial benefits, and environmental impacts in order to improve its use and widespread dissemination as a renewable energy source, a highly effective organic fertilizer, and economic benefits for the betterment of SSA communities, more well-organized work and adequate research activities should be initiated and supported. The findings may be useful to researchers, practitioners, and policymakers who support/promote sustainable energy and waste management strategies in low-resource settings.

The study intends to present the bioenergy potential in Ethiopia using major sources of biomass generation. The study utilized data from secondary sources to generate the potential using the available biomass sources within the country. In order to determine the bioenergy potential, four residue biomass sources, including livestock manure, crop residues, forest residues, and municipal solid waste (MSW) from major cities, were considered. The Food and Agriculture Organization Corporate Statistical (FAOSTAT) Database as well as national and local reports were used to compile information on crops, forests, animals, and human populations. The potential of each source is estimated for 2020-21 as the base year. The total bioenergy potential of the country is estimated to be 2955petajoule (PJ) per year, with 56.01 of it coming from forest residue, 28.29 from crop residue, 15.36 from livestock waste, and 0.33 from MSW. In addition, it is estimated that 819.7terawatt hours (TWh) of electricity may be generated from all sources yearly. This is equivalent to around 8, 58, and 89 times Ethiopias total primary energy consumption, electricity production, and electricity net consumption in 2020, respectively. Results also demonstrated that the total potential (819.7TWh·y⁻¹) is roughly 56 greater than the forest residues potential alone (459TWh·y⁻¹). This implies that biomass resources might be crucial in assisting Ethiopia to fulfill its future energy needs. To fully realize the availability of biomass energy, the study suggests performing integrated development research, choosing the best feedstock and value chains for bioenergy, and creating a bioenergy database.

This study assessed the performance of Pleurotus ostreatus and Lentinula edodes mushrooms on a variety of substrate combinations. Water hyacinth, rice husk, and cow dung were employed as substrates. Mushroom growth performance, yield, proximate composition, and mineral content were among the variables evaluated. The results indicate significant differences (p < 0.05) in spawn run duration, first harvest duration, total yield, and biological efficiency among the substrate combinations for the mushroom species. The substrate combination of 80% water hyacinth and 20% cow dung consistently exceeded the performances of others, demonstrating higher total yield (863.00 and 799.81 g/bag) and biological efficiency (88.51% and 82.03%) for P. ostreatus and L. edodes mushrooms, respectively. Proximate analysis results also demonstrated that this substrate combination produced mushrooms with higher protein (14.72 and 12.04%) and carbohydrate (55.11 and 58.05%) contents for P. ostreatus and L. edodes, respectively. P, K, Mg, Na, Ca, Fe, Zn, and Cd levels in P. ostreatus samples ranged from 1700 to 2700, 28100 to 39500, 1600 to 7800, 291.55 to 400.23, 310.37 to 372.70, 26.42 to 45.47, 61.87 to 70.40, and 1.13–1.25 mg/kg on average, respectively. The levels for P, K, Mg, Na, Ca, Fe, Zn, and Cd ranged from 19700 to 22700, 22500 to 25000, 2100 to 2500, 250.96 to 300.90, 284.66 to 296.19, 24.04 to 29.49, 74.03 to 83.98, and 1.31–1.45 mg/kg for L. edodes samples. The evaluated mushrooms grown on the various substrate combinations contain higher major and minor minerals needed in the human diet than toxic elements. This indicated that the evaluated edible mushrooms had high important mineral levels and could be considered a good source of vital elements. They are also very good at balancing nutrient supply scarcity, which is common in developing countries like Ethiopia. However, according to the World Health Organization's permissible limits for human intake, adequate attention and control of daily dietary intake is necessary for specific elements.

Ziziphus mauritiana is used as food and medicine. It is very nutritive and contains high amounts of calcium, phosphorus, iron, vitamin C, and beta-carotene. To choose an appropriate technique for fruit preservation, this study evaluated the effect of temperature and time on the nutritional and anti-nutritional qualities of Ziziphus mauritiana fruit harvested from Kobo Woreda in North-Eastern Ethiopia. This study assessed the impact of preservation parameters on the nutritional and anti-nutritional properties of Ziziphus mauritiana fruit, such as storage temperature and preservation day (time). Ziziphus mauritiana fruit was also analyzed to evaluate storage temperature and preservation day on its nutritional and antinutritional composition and found moisture content (5.25–10.99%), ash content (4.74–10.70%), crude fiber (3.81–17.88), fat (0.49–2.16), nitrogen content (1.01–1.8%), protein content (6.33–11.27), phytate content (67.27–659.33 mg/100 g m), and tannin content (3842.46–16577.80 mg/100 g m). The findings revealed that both individual and interaction effects were highly significant differences (p-value, 0.0001) in each nutritional and antinutritional content of the fruit. The results of this study showed that it was possible to store Ziziphus mauritiana fruit using plastic bags (High-Density Polyethylene Bags), and further deep-freezing the fruit had the best effect on preserving it in its fresh state (without damage) for up to 45 days.