Biomass and Biogas as Energy Source in Agrifood Systems
Biogas is a gas that is produced during anaerobic degradation of organic materials. It is composed of methane (60 – 70 percent) and carbon dioxide (30 – 40 percent) and contains also trace amounts of other components (water vapor, hydrogen sulphide and ammonia). 30 million tons of methane emissions are produced worldwide each year from agricultural operations. As a greenhouse gas (GHG) with a global warming potential of 25 times that of carbon dioxide, methane has detrimental effects on the environment and the climate.
However, biogas could cover around 6 percent of the global primary energy supply. By using waste such as feedstock, anaerobic digestion allows energy recovery, closing the nutrient cycle and acting as a measure for climate change mitigation and pollution reduction, as it replaces energy from traditional fossil fuels. The main challenges for implementing biogas as an energy source are the lack of information, governmental policies, trained labour force, and its high costs.
. All energy derived from biofuels, which can be subdivided into three types: solid, liquid and gas. Biofuels are fuels derived from biomass and depending on its origin they can also be classified as fuels from forest, agriculture or municipal waste. The basic bioenergy process involves the translation of organic material into an end product, including biogas, which can then be used to produce energy. Main feedstocks used are food waste, farm manures and slurries, and crop residues.
The technologies available for bioenergy conversion can be classified into three general categories: thermochemical, biochemical and other processes. Thermochemical processes include direct combustion, pyrolysis and gasification. Most used biochemical processes are anaerobic digestion and fermentation. Other processes include transesterification, which is a process that converts oils or fats into biodiesel, or cold pressing, which involves mechanical applications. Despite their abundancy, bioenergy resources are underutilized. With the wide range of available feedstocks, and different extraction technologies, there are many opportunities across many sectors to implement bioenergy projects.
Actors & Innovations
Biomass and Solar PV Hybrid Minigrids for Off-Grid Farming Communities
Rural off-grid communities that rely on solar PV systems have limited access to electricity and therefore limited hours for agricultural operations. As diesel generators and battery back-ups are expensive to operate, the innovator Husk Power has developed a hybrid solution that combines biomass gasification with solar power.
The biomass plant converts abundant agricultural residue, such as maize cobs, rice husks, coffee husks and cotton stalks into electricity, powering a mini grid for residential and agricultural uses. The electricity is distributed to rural households and micro-enterprises, allowing a better quality and providing a low-cost option for meeting their energy needs. It powers irrigation pumps, agro-processing mills, and drying and heating processes. As both resources are abundant in rural communities, the processing operations will be able to continue during night time, as the biomass plant will provide power when the solar PV system is not operating.
Mobile Biomass Steam Plants for Rural Communities
In sub-Saharan Africa, the limited access to modern energy services leads to a slow adoption of modern agriculture practices, resulting in sparse irrigation, reduced food production and few opportunities for value-adding processing and refrigerated storage.
Village Industrial Power (VIP)’s steam plants powered through combustion of biomass waste generate mechanical, electrical and thermal energy for a diverse range of agricultural activities and for residential and commercial end-users. As a mobile power plant unit, it is robust, reliable and works on demand, contributing to the community’s financial stability and entrepreneurship opportunities. The thermal energy generated can also be used to power other motors, dry crops or produce hot water for the milling process, but also for residential uses.
Biomass-Powered Thermal Processing of Ethiopian Bamboo
African Bamboo is a forestry, wood, and bio-energy company located in Addis Ababa, Ethiopia, where Africa’s largest reserves of bamboo are located. African Bamboo develops innovative applications for bamboo, particularly for industrial and commercial uses. As a fast-growing and largely sustainable raw material, there is an increasing global demand for bamboo as a wood substitute for a variety of construction and furnishing applications. However, modern value-added processing techniques are poorly known, which limits the income generation potential.
African Bamboo has developed an environmentally friendly bamboo thermal modification called ThermoBoo. Eliminating decay factors, the thermally modified bamboo fiber can be processed into sturdy panels ready for the market to a range of domestic and international buyers. The innovation opens up new opportunities for export, employment and manufacturing in Ethiopia, improving the livelihood of the local community through job creation. New micro and small enterprises for bamboo forest harvesting and transportation can provide local farmers with fair and stable income. Besides its socio-economic impact, bamboo cultivation of native species plays a significant role in reforestation by stabilizing soil.
Biogas Milk Chilling for Dairy Farmers
In the emerging dairy industry in East Africa, the demand is expected to double in the coming years. However, only 15 percent of milk produced reaches the formal market, partly due to the lack of access to a reliable power grid for cooling. As there had been a lack of solutions available on the market to provide milk chilling technologies at micro-scale, SimGas together with SNV developed a small-scale biogas-powered milk chiller for smallholder farmers in Kenya, Tanzania and Rwanda.
Biogas-Powered Evaporative Cooling for the Dairy Industry
The growing dairy industry throughout sub-Saharan Africa suffers from a lack of proper refrigeration options, which causes farmers to lose 20-50 percent of their milk to spoilage. The University of Georgia Research Foundation (UGARF) together with the Smallholder Fortunes small scale demonstration dairy farm in Uganda have developed the EvaKuula: a biogas unit that works with cow manure and allows a mild heat treatment of the milk, followed by a gentle evaporative cooling process, keeping the milk fresh overnight. Working with local manufacturers, financing models are being developed to bring the local production to commercial scale.
Using the EvaKuula, smallholder dairy farmers not only profit from access to clean energy, which can be used for lighting and cooking, but also reduce greenhouse gas emissions from cow manure fermentation. 42 farmers have benefitted so far from the deployment of this device, half of the beneficiaries being women, who furthermore helped during product design to make it more female-friendly.
Biomass Potential in the Indonesian Agroindustry
The potential of converting biomass waste from the Indonesian Agroindustry into electricity would reduce greenhouse gas emissions and ease rural electrification. The analysed crops palm oil, rice paddy and sugar cane count for 80 percent of all residues in the Indonesian agroindustry and would have a theoretical potential for electricity generation of 328 TWh per year. However, considering grid availability, the technical potential is lower with 43 TWh/year, which would reduce 39 million tons of CO2 per year and cover 25 percent of Indonesia’s electricity demand. The economic potential calculation shows that only projects using biogas from palm oil effluents with very short distance to the grid and high processing capacities can be considered.
Biogas Technology in Vietnam
The use of biogas is common in the Mekong delta and is used as a supplement to farming activities on a household scale. The reasons for its good acceptance are the savings on fuel and the convenience of biogas compared with firewood or kerosene. However, on a larger scale, this energy alternative has less attention and attraction, despite the great potential waste treatment and energy conversion bares within these intensive and specialized farms, which, furthermore, cause large amounts of pollution. If implemented on medium to large-scale farms, biogas production will be higher than the domestic demand.
Biogas for the Small Holdings in Kerala, India
Traditional farmers in Kerala, India, have mostly small holdings (< 1 ha) under multi-cropping systems with several perennial crops grown side by side. To make these fragmented farms viable, they are integrated with various sub-systems like dairying, poultry, apiculture, piggery, producing high amounts of biomass. This can be used to produce energy for the farm.
The Deenabandhu type of biogas plant with a fixed dome is very popular in the country, as it is a simple and practical model that does not require any additional power source for feeding it. Also, for garbage disposal from hotels, slaughter houses and public market, this biogas plant is a practical solution that promises safe and economical disposal of wastes and energy production. The biogas slurry obtained after digestion is enriched manure that can be applied to the crops, being a solution for soil nutrition. Especially the climatic conditions of the humid tropics are decisive for this eco-friendly option.
Have Improved Cookstoves Benefitted Rural Kenyans?
Cooking accounts for an estimated 2 percent of all greenhouse gas emissions worldwide, and cooking using firewood produces 45 percent of the CO2 emissions attributed to cooking. EnDev Kenya, a division of GIZ (the German development agency), has been promoting improved cookstoves (ICS) since 2006 in collaboration with the government of Kenya, nongovernmental organizations, and private firms.
They promote two types of energy-efficient and improved cookstoves: the Jiko Kisasa, 40 percent more efficient, and the Rocket stove, 20 percent more efficient. Both are produced locally, use firewood, and have no chimneys but provide good combustion. As of December 2017, about 9.6 million people had benefitted from it. According to EnDev, ICS lowered firewood consumption by 638,000 tons (corresponding to 38,000 hectares of forest) and cut CO2 emissions by more than 738,000 tons between 2016 and 2017. On average, the improved cookstoves reduced fuel consumption by about 20-32 kg a month (about 18-29 percent of consumption). As ICS adoption reduced the time women spent collecting biomass fuels by 92-105 minutes a week, it also increased the time women spent on income-generating activities, childcare, and leisure. Furthermore, ICS reduced some of the symptoms associated with exposure to household air pollution. It has also helped to develop the cookstove market in the rural Kenya, creating jobs in the production, marketing and installation of stoves. Some 4,200 previously unemployed people (mostly women and youth) have become self-employed in the ICS market. Read more…
Publications & Tools
Bioenergy for Agricultural Production
The increasing agricultural intensification has led to a rapid growth of agricultural biomass waste, which during natural decomposition processes emits methane, a greenhouse gas with 25 percent higher global warming potential than carbon dioxide. Burning biomass to clear lands for agricultural purposes is also a common practice among farmers, which additionally produces CO2 and other local pollutants. Inappropriate waste management is contributing to climate change, water and soil contamination, and local air pollution. Furthermore, this waste material has a high energetic value and can be used for energy production, climate change mitigation, and soil amendment among others.
To raise awareness, UNEP has started to promote Integrated Solid Waste Management (ISWM) based on the 3R (reduce, reuse and recycle) principle, covering all waste streams and all stages of the waste management chain: source segregation, collection and transportation, treatment and material/energy recovery and final disposal. Developing and implementing ISWM requires comprehensive data on present and anticipated waste situations, supportive policy frameworks, knowledge and capacity to develop plans/systems, proper use of environmentally sound technologies, and appropriate financial instruments to support its implementation. To raise awareness and build the local capacity for the design and implementation, UNEP has started a compilation of technologies for converting waste agricultural biomass into material/energy source.
Biomass Energy Sector Planning Guide (BEST)
Although negative perceptions of biomass energy are widespread, it is not necessarily an unsustainable or backward fuel. Its sustainability depends on the practices applied in the value chain, including forest management techniques and the efficiency of conversion and use. Moving biomass activities to the formal sector by establishing a suitable and functioning regulatory framework provides security for producers and traders to invest in better and more sustainable production methods. The Biomass Energy Sector Planning Guide assists stakeholders in government institutions in the development of efficient and coordinated management strategies in the biomass energy sector. These are developed along six stages: analysis and team formation, baseline sector analysis, scenario development, intervention formulation, strategy and action plan monitoring, and finally adoption and implementation of the agreed activities. The Guide can also be used as a tool by civil society actors and donor agencies for raising awareness about the importance of the biomass sector.