By Abbas Nazil
Household biogas plants can significantly reduce fuelwood consumption and carbon emissions in rural Ethiopia, with a new study finding that each plant could save more than 1.1 tonnes of fuelwood and prevent about 1.6 tonnes of carbon dioxide equivalent emissions annually.
The study, conducted in Girar Jarso district of North Shoa, found that households using biogas consumed substantially less fuelwood than those relying on traditional three-stone fires.
Researchers from Madda Walabu University and Salale University examined the use of household biogas technology and its potential to reduce pressure on forests while providing cleaner cooking energy in rural communities.
The study involved 345 households across Goticho Safane, Wertu and Torban Ashe kebeles, including 50 biogas-adopting households and 295 non-adopters.
The researchers also conducted interviews with key informants, focus group discussions and field observations to understand household energy use and the factors influencing adoption.
Direct measurements of fuelwood consumption were carried out through a Kitchen Performance Test involving 36 households, equally divided between biogas users and non-users.
The results showed that biogas-adopting households used an average of 4.6 kilograms of fuelwood per day at household level, compared with 7.7 kilograms among households without biogas.
The study estimated that each household biogas plant saved about 1,131.5 kilograms of fuelwood annually, demonstrating its potential to reduce dependence on wood-based energy.
The researchers also calculated that the reduction in fuelwood consumption translated into an estimated annual avoidance of about 1.6 tonnes of carbon dioxide equivalent for each biogas plant.
The findings are particularly relevant to Ethiopia, where traditional biomass remains a major source of household energy and continued fuelwood harvesting contributes to pressure on forest resources.
The study noted that fuelwood scarcity is already affecting rural households in Girar Jarso, with women and families facing increasing difficulties in obtaining traditional cooking fuels.
Biogas provides an alternative by converting organic waste, particularly livestock manure, into combustible gas through anaerobic digestion.
The gas can be used for cooking and lighting, while the remaining slurry can be applied as a fertiliser.
The technology therefore provides both an energy source and a potential way of recycling agricultural and livestock waste.
The researchers found that livestock ownership was among the strongest factors associated with adoption because households with more cattle have greater access to the manure needed to operate digesters.
Household size and annual income were also significant factors influencing adoption, while access to adequate water was important because water is required for mixing and processing the digester feedstock.
The findings also indicated that the age and gender of household heads did not significantly determine whether households adopted the technology.
The study identified eucalyptus as the most commonly used fuelwood species in the area, with Eucalyptus globulus reported by 69.5 per cent of respondents.
Researchers linked the reliance on fast-growing eucalyptus to pressure on natural forests and the increasing scarcity of other fuelwood resources.
Beyond reducing fuelwood demand, biogas could also improve household air quality because biogas stoves produce substantially less particulate matter than traditional wood-burning cooking systems.
The researchers noted that traditional firewood stoves can produce high levels of particulate emissions, while biogas combustion produces considerably lower amounts.
However, the study identified high initial investment costs as an important barrier to wider adoption, particularly among poorer households.
Limited access to water, maintenance challenges and uneven support for the technology can also restrict its expansion in rural communities.
The researchers said financial assistance and awareness programmes could help more households adopt biogas, particularly those with limited resources.
They also highlighted the importance of reliable water supplies for the successful operation of household digesters.
The researchers cautioned that the study focused on a single district and therefore its findings may not represent all rural areas of Ethiopia.
Nevertheless, the results demonstrate the potential of household biogas to reduce fuelwood demand, lower emissions and provide a cleaner energy option for communities that remain heavily dependent on biomass.
