Engineering Aspects of Small-Scale Biogas Plants

Small-scale electrical power generation (<100 kW) from biogas plants to provide off-grid electricity is of growing interest. Currently, gas engines are used to meet this demand. Alternatively, more efficient small-scale solid oxide fuel cells (SOFCs) can be used to enhance electricity generation from small-scale biogas plants. Most electricity generators require a constant gas supply and high gas quality in terms of absence of impurities like H2S. Therefore, to efficiently use the biogas from existing decentralized anaerobic digesters for electricity production, higher quality and stable biogas flow must be guaranteed. The installation of a biogas upgrading and buffer system could be considered; however, the cost implication could be high at a small scale as compared to locally available alternatives such as co-digestion and improved digester operation. Therefore, this study initially describes relevant literature related to feedstock pre-treatment, co-digestion and user operational practices of small-scale digesters, which theoretically could lead to major improvements of anaerobic digestion process efficiency. The theoretical preamble is then coupled to the results of a field study, which demonstrated that many locally available resources and user practices constitute frugal innovations with potential to improve biogas quality and digester performance in off-grid settings.

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Rural Energy in Kenya: Is There a Future for Biogas? A Survey

Energy Exploration & Exploitation ◽

10.1177/014459878900700205 ◽

1989 ◽

Vol 7 (2) ◽

pp. 116-127 ◽

Cited By ~ 2

Author(s):

Justas K. Laichena

Keyword(s):

Crop Residues ◽

Muscle Power ◽

Gas Production ◽

Energy Crisis ◽

Small Scale ◽

Ic Engine ◽

Rural Energy ◽

Animal Dung ◽

Biogas Plants ◽

Biogas Technology

Most rural people in Kenya rely principally on human and animal muscle power in their work as subsistence farmers, herdsmen, fisherman, or small-scale crop farmers. All the agricultural processes (ranging from ploughing to harvesting) are done largely by hand, with some help from draft animals and simple tools. Firewood is their principal cooking and heating fuel while kerosene in used for lighting. Their economic growth is hence blocked by the energy crisis. Due to their heavy dependence on biomass – mainly firewood, crop residues, and animal dung – they deprive the soil of essential nutrients and pose a threat to the agricultural lands due to deforestation and the resulting soil erosion. The problem of rural energy, therefore places the provision of food and other basic needs at risk. A technology which extracts a more useful and convenient form of fuel from biomass without destroying its fertilizer value than the traditional conversion method of direct combustion is highly desirable. Anaerobic digestion of agricultural residues generates biogas which can be used directly for lighting, cooking, electricity generation, or to power an IC engine for water pumping or milling. The remaining sludge forms a good fertilizer. This paper reviews the role of biomass in meeting Kenya's energy needs and how biogas can contribute in alleviating the rural energy crisis. Biogas production and utilization technology was introduced in Kenya in 1954 but by 1986 there were less than 200 installed biogas plants and less than 25% of these were operational. A survey of installed biogas plants (across the country) was carried out (using questionnaires and interviews) to identify the factors that have inhibited the adoption of biogas technology in Kenya; and the problems which have caused the failure of many of the installed plants. The paper gives a detailed discussion of the findings. The survey showed that amoung the reasons for nonadoption are: lack of capital and sufficient input materials (animal dung and water); limited dissemination of technical knowledge and experience to operate biogas plants; and the lack of credit and extension facilities. It was also found that problems such as scum build-up and corrosion, and the lack of sufficient knowledge on the operation and maintenance of the digesters especially on feeding and feedstock dilution (leading to low gas production) has resulted to many failures. The paper attempts to answer some of the problems which have resulted to the many failures and hindered widespread acceptance of biogas technology in Kenya. Finally the issue of dissemination is discussed.

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Absorption Chillers to Improve the Performance of Small-Scale Biomethane Liquefaction Plants

Energies ◽

10.3390/en15010092 ◽

2021 ◽

Vol 15 (1) ◽

pp. 92

Author(s):

Alessio Ciambellotti ◽

Gianluca Pasini ◽

Andrea Baccioli ◽

Lorenzo Ferrari ◽

Stefano Barsali

Keyword(s):

Natural Gas ◽

Waste Heat ◽

Economic Assessment ◽

Specific Consumption ◽

Small Scale ◽

Agricultural Activities ◽

Electricity Cost ◽

Absorption Chillers ◽

Levelized Cost ◽

Biogas Plants

Biomethane liquefaction may help decarbonization in heavy transportation and other hard-to-abate sectors. Small-scale liquefaction plants (<10 ton/day) are suitable for small biogas plants located near farms and other agricultural activities. “Internal refrigerant” refrigeration cycles (e.g., Kapitza cycle) are often proposed for small-scale natural gas liquefaction due to their simplicity. An optimized Kapitza-based cycle is modeled and simulated, and then several modifications were studied to evaluate their influence on the energetic and economic performances. Results showed a specific consumption ranging between 0.65 kWh/kg and 0.54 kWh/kg of bio-LNG with no significant improvements by increasing cycle complexity. Instead, a reduction of 17% was achieved with the implementation of absorption chillers, that effectively turn waste heat into useful cooling energy. An economic assessment was finally carried showing that the Levelized Cost of Liquefation is more affected by electricity cost than additional CapEx.

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Effects of the German Renewable Energy Sources Act and environmental, social and economic factors on biogas plant adoption and agricultural land use change

10.21203/rs.3.rs-61754/v2 ◽

2020 ◽

Author(s):

Xueqing Yang ◽

Yang Liu ◽

Daniela Thrän ◽

Alberto Bezama ◽

Mei Wang

Keyword(s):

Land Use ◽

Agricultural Land ◽

Biogas Production ◽

Renewable Energy Sources ◽

Energy Sources ◽

Small Scale ◽

Agricultural Land Use ◽

Economic Factors ◽

Silage Maize ◽

Biogas Plants

Abstract Background: The German energy transition strategy calls for a reform of the German energy sector. As a result, the Germany Renewable Energy Sources Act (EEG) was passed in 2000 and is widely regarded as successful legislation for promoting bioenergy development. More than 1,000 biogas plants were constructed in Central Germany (CG) between 2000 and 2014. Despite this, few studies have been conducted for this period that systematically investigate how environmental, social and economic factors, as well as various EEG amendments have impacted biogas production and what the environmental consequence of biogas production development in CG have been. Methods: The impacts of environmental, social and economic factors and different EEG amendments on biogas production decisions in CG were quantified using multivariate linear regression model and the event study econometric technique. A GIS-based spatial analysis was also conducted to provide insight into the changes to agricultural land use that resulted from the development of biogas plants during the EEG period. Results: The main finding was that the income diversification effect resulting from biogas production was the most important factor in a farmer’s decision to adopt biogas production. In addition, all of the EEG amendments had a significant influence on the adoption of biogas production, however EEG III and IV, which tried to promote small-scale plants, were unable to reduce the average size of the plants constructed in these two amendment periods. From a landscape perspective, there was a striking increase in the cultivation of silage maize in CG from 2000 to 2014. Silage maize was intensively cultivated in regions with a high installed biogas plant capacity. Since the first EEG amendment, permanent grassland area slightly increased while arable land area declined in CG. Conclusions: The adoption of biogas production in CG was strongly driven by economic incentives for the farmers, more precisely, by the incentive to diversify their income sources. In addition to increase the subsidy, future EEG amendments should find new measures to encourage the adoption of small-scale biogas plants, which had been unsuccessful in EEG amendments III and IV.

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Life cycle assessment of a small-scale methanol production system: A Power-to-Fuel strategy for biogas plants

Journal of Cleaner Production ◽

10.1016/j.jclepro.2020.122476 ◽

2020 ◽

Vol 271 ◽

pp. 122476 ◽

Cited By ~ 3

Author(s):

Lea Eggemann ◽

Neus Escobar ◽

Ralf Peters ◽

Peter Burauel ◽

Detlef Stolten

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Production System ◽

Small Scale ◽

Methanol Production ◽

System A ◽

Biogas Plants

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Addressing problems at small-scale biogas plants: a case study from central Vietnam

Journal of Cleaner Production ◽

10.1016/j.jclepro.2015.09.114 ◽

2016 ◽

Vol 112 ◽

pp. 2784-2792 ◽

Cited By ~ 24

Author(s):

Hynek Roubík ◽

Jana Mazancová ◽

Jan Banout ◽

Vladimír Verner

Keyword(s):

Small Scale ◽

Central Vietnam ◽

Biogas Plants

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Small-Scale Composting Bioreactors as a Part of Biogas Plants

Small Bioreactors for Management of Biodegradable Waste ◽

10.1007/978-3-319-78211-9_7 ◽

2018 ◽

pp. 263-300

Author(s):

Pranas Baltrėnas ◽

Edita Baltrėnaitė

Keyword(s):

Small Scale ◽

Biogas Plants

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Feasibility analysis of small-scale biogas plants usage in the Syrian coast through agricultural crop residues and co-digestion of manure

Biomass Conversion and Biorefinery ◽

10.1007/s13399-021-02112-6 ◽

2022 ◽

Author(s):

Ghaith Hasan ◽

Jana Mazancová ◽

Jan Banout ◽

Raed Jafar ◽

Hynek Roubík

Keyword(s):

Crop Residues ◽

Feasibility Analysis ◽

Small Scale ◽

Agricultural Crop ◽

Biogas Plants ◽

Syrian Coast

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Dairy Waste and Potential of Small-Scale Biogas Digester for Rural Energy in India

Applied Sciences ◽

10.3390/app112210671 ◽

2021 ◽

Vol 11 (22) ◽

pp. 10671

Author(s):

Prachi Pandey ◽

Aditya Pandey ◽

Long Yan ◽

Dengshan Wang ◽

Vinay Pandey ◽

...

Keyword(s):

Developing Countries ◽

Greenhouse Gases ◽

Fossil Fuels ◽

Rural Environment ◽

Small Scale ◽

Livestock Waste ◽

Biogas Plants ◽

Reduce Emissions ◽

The Cost ◽

Biogas Technology

In order to reduce emissions of greenhouse gases, related global warming and dependency on fossil fuels, it is crucial to promote the uses of renewable energy, and conversion of biomass and organic waste into energy sources. In many parts of the world, a substantial increase in efforts for the conversion of waste into energy is currently being observed. Specifically, biogas technology has been emphasized for the conversion of animal waste into biomethane/biogas because livestock waste is considered to be a substantial source of ambient greenhouse gases, causing climate change. While biogas technology, an anerobic process to convert livestock waste into biogas, is promoted in both developed and developing countries, this review article is focused on improving our existing understanding of small-scale biogas technology and relevance of this technology in rural environment of India. A thorough review research has been performed to gather the information on livestock population, manure production, and potential of biogas technology in India to provide a wholistic information. A summary of the financial supports facilitated by various agencies, the cost of biogas plants, potential uses, and potential challenges in the dissemination of biogas technology in India has been discussed in this study. We anticipate that the data and interpretation provided here will help in understanding the scope of biogas technology in India and will help in formulating the policies which will support the implementation of biogas technologies in developing countries.

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