Small Biogas Plants Research Articles

Life Cycle Assessment of Perishable Wastes from Koyambedu Market

India is the second largest country having highest population which leads to generation of large sum of wastes. Municipal solid waste generally consists of household and commercial waste. Most of the wastes are collected and dumped in the landfill sites but in certain cases these wastes are dumped in nearby empty places which causes environmental pollution and also leads to spreading of various diseases. Koyambedu Market situated in Chennai, Tamil Nadu is one of the largest markets in Asia having a total area of 295 acres with different shops selling vegetables, fruits, flowers and meats. Around 300 tons of wastes are generated in a day from the entire market. The collected data are analyzed using Life Cycle Analysis (LCA) to know the impact caused by the wastes that are disposed from Koyambedu. The methodology of LCA makes modelling simpler, gives more clearly defined system boundaries, and reduces the amount of data that is required in comparison to the conventional method of independently comparing two different criteria. The use of LCA is more feasible in order to find the life cycle of the wastes and to find which waste produces more harm to the environment. With the analyzes it was found the emission of methane is more in vegetable waste than in other wastes that are collected from the market. The electricity consumed by landfill is less compared to the biogas plant. It is suggested that small biogas plants can be built near the markets to extract the gases that are produced from the wastes.

Operation of a Pilot-Scale Biogas Plant Made of Textile Materials and Application of Its Results to a Full-Sized Demonstration Plant

In small German farms, there is a technically usable potential of cattle manure and pig manure ranging from 153 to 187 million tons of fresh matter per year. Since 2021 and 2023, new incentives under the Renewable Energy Sources Act (EEG) have been promoting biogas production in small farms. These incentives, applicable to biogas plants up to 150 kWel, include direct compensations for plants up to 100 kWel and market premiums for those up to 150 kWel. A small biogas plant made of textile materials was designed for both pilot and full-scale applications. Compared to conventional concrete biogas reactors, these textile-based reactors offer a simplified construction and operation, eliminating the need for specialized civil engineering. The primary objective of this research is to demonstrate the process engineering feasibility of biogas reactors based on textile materials for small farm biogas plants (30 to 75 kWel). Another goal is to design the construction method in such a way that this type of system can be built by farmers themselves after type testing on site. Operational insights were gathered from the laboratory plant with a 300-L digester volume, using cattle manure and clover grass silage. To adapt the system to the biogas reactor made of textile materials, the reactor was designed without a stirrer. These insights were considered in the design and approval procedure of the full-sized demonstration biogas plant made of textile materials. The full-size demonstration plant digesters underwent an approval procedure from local authorities, featuring treatment volumes of 120 m3 for the main biogas reactor and 550 m3 for the digestate reactor in an earth basin style. This new type of biogas plant could be built in small farms for self-sufficiency in electrical and thermal energy or for treating sewage sludge in small-scale communal wastewater treatment and biogas plants.

The energetic and economic analysis of demand-driven biogas plant investment possibility in dairy farm

The paper aims to analyze the energy and economic effect of a demand-driven biogas investment versus a conventional one in modern dairy farm facilities of medium scale. Demand-driven exploitation may be the only way to obtain permission for connection to energy grid of new renewable energy sources (RES) installations in administrative regions where intermittent RES i.e. photovoltaics provide a large amount of energy to the grid. The biogas plant cogeneration capacity is meant to respond to demand out of the time range of intense electricity generation from photovoltaic farms.The energetic and economic analysis showed that the investment in the biogas plant would be profitable (payback period of 3.41 years in the best scenario), achieved thanks to operating as demand-driven biogas plant with CHP 499 kWe working 12 h/day (4250 h/year). Since the biogas plant is planned to operate as a demand-driven installation, it would also be possible to perform service inspections of the cogeneration unit (CHP) when it is not working. As a result, this small biogas plant (250 kW) with 499 kW CHP can produce as much as 2126 MWh/year. The second aspect of profitability is the use of biomass (mainly biowaste) from a farm as a substrate.

The Impact of Manure Use for Energy Purposes on the Economic Balance of a Dairy Farm

The use of methane fermentation in mesophilic conditions for the energy use of cow manure and additional co-substrates from the farm can bring a small dairy farm (140 dairy cows) financial benefits of up to EUR 114,159 per year. Taking into account the need to pay for emissions calculated as carbon dioxide equivalent, this profit could be reduced to EUR 81,323 per year. With the traditional direct use of manure, this profit would drop by as much as 60% to the level of EUR 33,944 per year. Therefore, the introduction of fees for emissions may significantly burden current dairy farms. As has already been shown, just compacting and covering the manure (which costs approx. EUR 2000 per year for 140 cows) would give almost twice as much profit—EUR 64,509 per year. Although an investment in a small biogas plant with a cogeneration unit on a family dairy farm may have a payback period of less than 6.5 years and a return of capital employed of 16%, most small farms in the world will not be able to afford its construction without external subsidies. At the same time, it would make it possible to reduce emissions by almost 270 times—from 41,460 to 154 tons of CO2eq per year—and the possibility of preserving valuable nutrients and minerals and supporting soil properties in the digestate. Therefore, it seems necessary for Europe to introduce a support system for small- and medium-sized farms with this type of investment in the near future in a much larger form than it has been so far.

Importance of Feedstock in a Small-Scale Agricultural Biogas Plant

Although no legal sustainability criteria have been formulated for electricity and heat production from biogas, the sustainability and profitability of large-scale biogas plants which use mainly energy crops is now questioned. Small (farm-size) biogas plants characterized by CHP electrical output in the range between 15 kWel and 99 kWel, operating on agricultural wastes and by-products, seem more suitable; however, the variety of feedstock may be crucial in the proper design and operation of such family biogas plants. This paper aims to present the problems that occurred in small agricultural biogas plants fed with sheep manure (SM), horse manure (HM), and grass-clover silage (GCS). This paper also focuses on analyzing the energy balance and carbon dioxide (CO2) emissions related to four technological solutions (Scenarios 1–4) based on various feedstocks, grinding and feeding systems, and wet/dry fermentation. The biogas plant was originally based on dry fermentation with an organic loading rate ~10.4 kgVS·m−3·d−1, a hydraulic retention time of 16 days, and temperature of 45 °C in the fermentation chamber. The material was shredded and mixed in a mixing device, then the mixture of manures and silage was introduced to the horizontal fermentation chamber through a system of screw feeders. The biogas and the digestate were collected in a reinforced concrete tank. The biogas was sent to the CHP unit of an installed electrical power of 37 kWel, used to produce electricity and recover the heat generated in this process. Scenario 1 is based on the design assumptions used for the biogas plant construction and start-up phase. Scenario 2 includes a new feeding and grinding system, in Scenario 3 the feedstock is limited to SM and HM and wet fermentation is introduced. In Scenario 4, a dry fermentation of SM, HM, and maize silage (MS) is assumed. Avoided CO2 emissions through electricity and heat production from biogas were the highest in the case of Scenarios 1 and 4 (262,764 kg CO2·y−1 and 240,992 kg CO2·y−1) due to high biogas production, and were the lowest in Scenario 3 (7,481,977 kg CO2·y−1) because of the low specific methane yield (SMY) of SM and HM. Nevertheless, in all scenarios, except Scenario 3, CO2 emissions from feedstock preparation and biogas plant operation are much lower than that which can be avoided by replacing the fossil fuel energy for the electricity and heat produced from biogas. Our observations show that a small agricultural biogas plant can be an effective energy source, and can contribute to reducing CO2 emissions only if the appropriate technological assumptions are adopted, and the entire installation is designed correctly.

Great expectations—future scenarios for production and use of biogas and digestate in Sweden

Sweden aims to increase biogas production from anaerobic digestion (AD) from 2 to 7 TWh/year until 2030. This paper investigates the requirements, challenges and implications of such a development through qualitative and quantitative assessment of three scenarios. Seven key elements—national policies and policy instruments, regional policies and policy instruments, mobilization of feedstock, infrastructure for feedstock and gas, mobilization of actors, new production facilities, and stable and increasing demand—were defined for the scenario construction and were also used to structure the comparative analysis. Quantitatively, increasing the biogas production from 2 to 7 TWh is estimated to require up to 5 times larger digester volume and up to 12 times more AD plants, meanwhile producing 6–8 times more biofertilizers. While a centralized production structure would be more efficient, a decentralized structure with small biogas plants would facilitate the logistics of agricultural substrates and biofertilizers. New production capacity could be incentivized through new and increased production subsidies, as well as an increased demand for renewable energy. Regardless of how the goal is to be achieved, it will require collective efforts from both public and private actors to overcome the many challenges on the way.

Financial and functionality analysis of a biogas plant in Bangladesh

Installation of a biogas plant in a rural region has become a viable alternative energy source with a variety of health and environmental advantages. Though Bangladesh has enormous resources for biogas production, biogas energy production is infancy stage in Bangladesh. The study aims to explore the economic aspect of household-level biogas plants and determine the relationship between biogas plant functionality and different factors. For doing this, 300 biogas plant owners were interviewed from fifteen Upazilla in Bangladesh and respondents were chosen by a two-stage random sampling technique. The study shows by measuring partial budgeting, USD 294.80 per year can be earned by a family by introducing biogas plant. Cost-benefit analysis showed that a small biogas plant (USD 143.07/year) was most profitable, followed by a large biogas plant (USD 142.17/year). In discounted cost-benefit analysis, medium size biogas plant was found to be the most beneficial investment, followed by a small size biogas plant. Average NPV, BCR, PBP, and IRR of Biogas plant were USD 1629.11, 1.77, 2.93, and 48% with subsidy where USD 1525.25, 1.77, 3.75, and 43% without subsidy. The measurement of carbon trading also highlights the economic benefit of a biogas plant in Bangladesh. The bivariate relationship between the functionality of biogas plants with different factors highlights that higher educated, trained plant owners with quality mason and follow up services ensured the efficient operation of the biogas plant.

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

Spatial planning and the development of renewable energy sources in Poland

Due to the damage to the environment and climate caused by the generation of electricity in power plants burning fossil fuels, installations generating it from renewable energy sources are constructed. Spatial development plans for communes should consider their location. In Poland, generation of electricity in photovoltaic cells, wind farms and agricultural biogas plants has the greatest development potential. Due to the nuisance to people and the environment, wind turbines and agricultural biogas plants must be located far from residential buildings. Such conditions exist in sparsely populated rural areas. The observed development of single-family housing in rural areas is the result of the search for cheap construction sites and no local spatial development plans in most areas of rural communes. Dispersed housing construction restricts the construction of wind farms and agricultural biogas plants and thus poses a threat to renewable sources of wind and biogas energy produced in agricultural biogas plants. The situation may be changed by the requirement to include in spatial development plans the needs related to the construction of installations generating electricity from renewable energy sources and the construction of micro and small biogas plants directly at the sites where waste is generated.

Unprofitability of small biogas plants without subsidies in the Brandenburg region

The circular economy is calling for the rapid use of already-developed renewable energies. However, the successful implementation of those new fuels is limited by economic and political issues. For instance, in the Brandenburg region, Germany, biogas production from anaerobic digestion of biomass and wastes is a current alternative. However, the upgrading biogas to biomethane is still challenging and the economic viability is unknown. Therefore, we performed an economic analysis for biogas upgrading to biomethane in the Brandenburg region. Five biogas plant sizes were analyzed by the method of discounted cash flow. This method yields the net present value of the projects, thus revealing the profitability or non-profitability of the plants. Results indicate profitable outputs for medium and large plants, with net present values between 415 and 7009 k€. However, the smallest plants have net present values from -4250 to -3389 k€, thus needing further economic efforts or subsidies to reach profitability. Indeed, biomethane prices should range between 52.1 and 95.6 €/MWh to make these projects profitable. Combinations of 50% of investment subsidized and 11.5 €/MWh feed-in tariffs subsidies could make the projects reach profitability. These findings reveal that political actions such as green policies and subsidies are needed to implement green energy. This case study should serve as a potential tool for policy-makers toward a sustainable bioeconomy.

Biogas Plant Exploitation in a Middle-Sized Dairy Farm in Poland: Energetic and Economic Aspects

Although cow manure is a valuable natural fertilizer, it is also a source of extreme greenhouse gas emissions, mainly methane. For this reason, this study aims to determine the impact of investments in a biogas plant on the energy and economic aspects of the operation of a dairy farm. A farm with a breeding size of 600 livestock units (LSU) was adopted for the analysis. In order to reach the paper’s aim, the analysis of two different scenarios of dairy farm functioning (conventional–only milk production, and modern–with biogas plant exploitation) was conducted. The analysis showed that the investment in biogas plant operations at a dairy farm and in using cow manure as one of the main substrates is a more profitable scenario compared to traditional dairy farming. Taking into account the actual Polish subsidies for electricity produced by small biogas plants, the scenario with a functioning biogas plant with a capacity of 500 kW brings €332,000/a more profit compared to the conventional scenario, even when taking into account additional costs, including the purchase of straw to ensure a continuous operation of the installation. Besides, in the traditional scenario, building a biogas plant allows for an almost complete reduction of greenhouse gas emissions during manure storage.

Microbiome Diversity and Community-Level Change Points within Manure-based small Biogas Plants.

Efforts to integrate biogas plants into bioeconomy concepts will lead to an expansion of manure-based (small) biogas plants, while their operation is challenging due to critical characteristics of some types of livestock manure. For a better process understanding, in this study, three manure-based small biogas plants were investigated with emphasis on microbiome diversity. Due to varying digester types, feedstocks, and process conditions, 16S rRNA gene amplicon sequencing showed differences in the taxonomic composition. Dynamic variations of each investigated biogas plant microbiome over time were analyzed by terminal restriction fragment length polymorphism (TRFLP), whereby nonmetric multidimensional scaling (NMDS) revealed two well-running systems, one of them with a high share of chicken manure, and one unstable system. By using Threshold Indicator Taxa Analysis (TITAN), community-level change points at ammonium and ammonia concentrations of 2.25 g L−1 and 193 mg L−1 or volatile fatty acid concentrations of 0.75 g L−1were reliably identified which are lower than the commonly reported thresholds for critical process stages based on chemical parameters. Although a change in the microbiome structure does not necessarily indicate an upcoming critical process stage, the recorded community-level change points might be a first indication to carefully observe the process.

The importance of governmental incentives for small biomethane plants in South Spain

Abstract A novel analysis addresses the economic viability of biomethane production from small biogas plants in South Spain, as a claim to promote the use of green energy and reduce the consumption of natural gas. To this end, the importance of governmental incentives to reach profitability in biomethane plants is illustrated through a case study. To date, no study addressing this problem specifically for South Spain can be found. The study considers the whole process from biogas production to biomethane feeding into the grid, for three different biomethane capacities (50, 100 and 150 m3/h) and includes an exhaustive sensitivity analysis. For the three cases, implementing a biomethane plant is not viable and, therefore, not attractive for investors. Results considering biomethane governmental incentives as feed-in premia show significant improvements on the profitability of the largest plants. For example, supporting 150 m3/h biomethane production capacity plants with a premium price of only 6 €/MWh (6.6 cents/m3) results in 270 k€ NPV. Nevertheless, the smallest biomethane plants are hardly feasible. Concerning governmental support through investment subsidies, 150 m3/h plants are profitable if 10% of the investment is subsidized, whereas the smallest plants do not reach profitability even if 50% of the investment is subsidized.

Micro-cogeneration based on solid oxide fuel cells: Market opportunities in the agriculture/livestock sector

Bio-waste embeds an extraordinary renewable potential, and it becomes a source of energy savings when transformed into a valuable resource, like biogas. Cogeneration (CHP) from biogas employing high-temperature Solid Oxide Fuel Cells (SOFCs) scores a high sustainability level, thanks to improved environmental and energy performances. The synergy between the niche market of small/micro biogas producers and SOFCs might act as a springboard to open market opportunities for both SOFC commercialization and business upgrade of small farms. However, local regulations, waste management, renewable energy subsidies and, above all, availability of eligible sites, determine real chances for on-the-ground implementation.Through a detailed analysis of the application scenario, this research aims at investigating opportunities for the experimentation of SOFC–CHP in small biogas plants and identifying the possible bottlenecks for future deployment. When it becomes relevant, energy conversion of livestock (especially cattle and swine) and agriculture waste requires SOFC modules from 10 kWe to 35 kWe. This is in line with the current status of SOFC suppliers. Moreover, considering the fuel cell market roll-out, the average levelized cost of electricity is expected to decrease from 0.387 €/kWh to 0.115 €/kWh, when electricity is produced from livestock waste available on-site.

Investigation on the influence of membrane selectivity on the performance of mobile biogas upgrading plants by process simulation

Upgrading technologies for producing a high quality biomethane from biogas are of growing interest due to phasing out of European feed-in tariffs for biogas-based electricity. Operators of small biogas plants need alternatives to common stationary upgrading plants due to their high investment cost. Mobile membrane-based upgrading plants can help to reduce those investment costs for single operators and therefore, new valorisation routes become accessible to them. Performance of membrane-based upgrading plants is highly dependent on the chosen plant design. As mobile upgrading plants are limited to a maximum of two stages for the membrane separation due to space and weight restrictions, performance can be influenced mainly by operational conditions and membrane module characteristics. In this study, the influence of the membrane's CO2/CH4 selectivity on the performance of the mobile upgrading plant was investigated. Rising the CO2/CH4 selectivity from 25 to 38.51 and 50 increased the recovery and the biomethane purity to a level comparable to those of stationary membrane-based upgrading plants.

Biogas production as an element of sustainable development of rural areas in EU and Poland

The article is devoted to the issue of sustainable rural development, with particular focus on biogas. It presents legal regulations in this area used in the European Union, including Poland. Additionally, the article provides the results of operational tests (conducted in 2011-2012) of a small biogas plant with total capacity of two reactors 411 m 3 . The cost of electricity production was on the level of 113.76 PLN•MWh -1 and heat production costs - 206.06 PLN•MWh -1 . The construction cost of biogas plant was equal 1100 PLN per cubic meter. The exploitation costs of biogas plant were 42450 PLN•year -1 as the cumulative costs: the annual cost of installation maintaining 27 000 PLN•year -1 and cost of use of the biogas plant was 5450 PLN•year -1 . The calculated profit from the sale of produced electricity was 100622 PLN•year -1 . The calculation has been prepared in accordance with the level of prices in Poland in the years 2011-2012.

The use of agricultural waste for the renewable energy production

In addition to hydroelectric power plants, solar and wind power plants, biogas plants are important in the production of electricity and heat from renewable energy sources. It is known that depending on the type of substrate used for processing and the design features of biogas plants, they have their own advantages and disadvantages. Nevertheless, properly localized biomass installation is able to decrease the use of conventional materials reducing greenhouse gas emissions. Bio-waste, plant residues and other by-products can be used to produce electricity, heat and purified methane as fuel for repaired vehicles. Biogas production is a key technology for the sustainable use of agricultural biomass as a renewable energy source. Both, Poland and Ukraine, have a large agricultural area, and well developed animal cattery, which creates opportunities for alternative energy sources from biomass development.
 Agricultural biogas plant energy produced from waste such manure, slurry and another agricultural waste, is an excellent source of heat, likewise, electricity. Therefore the importance of using agricultural waste as an energy source in the production of biogas shall be emphasized. A significant drawback of the system is the need to provide low economic and environmental losses. For this purpose, the place of biomass harvesting, transport and its preparation together with storage should be taken into account. To achieve the highest efficiency, small biogas plants should have permanent composition of substrate consisting of various ingredients.
 Ukraine and Poland has considerable potential of renewable energy sources development of which can provide significant economic, ecological, and social benefits. The production of biogas has become an attractive source of extra income for many farmers. Biogas production has a useful effect not only on economic, but ecological development, particularly in the rural regions. At the same time, environmental protection aspects have gained additional importance, so that anaerobic treatment processes have become a key technology for environmental and climate protection.
 On the basis of the submitted documentation by the municipal administration and the manufacturer, the operation of biogas plants for the processing of organic agricultural waste in Gorajec and Odrzechowa (Poland) has been presented.

A Blockchain-based Architecture for Stable and Trustworthy Smart Grid

Smart Grid represents an efficient power transmission, distribution and management system. However, solutions for Smart Grid have raised security and privacy problems. Moreover, with the introduction of renewable energy resources, such as rooftop solar panels and small biogas plants, more and more electricity consumers are involved in the energy generation system. This may cause the power system unstable and/or the waste of the energy. Blockchain is a promising technology for solving these problems in the future energy system on account of its distributed trust, anonymity, data integrity and availability. In this paper, we propose a Blockchain-based architecture for Smart Grid. By using the proposed architecture, electricity consumers can be fully involved in the energy system and tracing the details of the energy they have consumed or generated. At the same time, the stability of the energy system can be kept, reducing the waste of the energy and potential hazard to the electrical equipment.

Size, Subsidies and Technical Efficiency in Renewable Energy Production: The Case of Austrian Biogas Plants

This study estimates the efficiency of biogas plants and identifies determinants of inefficiencies. Data Envelopment Analysis is applied on a sample of 86 Austrian biogas plants for the year 2014, covering about one third of the installed electric capacity of Austrian biogas plants. We decompose technical efficiency into scale efficiency and pure technical efficiency (managerial efficiency). In a second-stage regression analysis the effects of subsidies and other variables on managerial efficiency are investigated. The main results are: i) 34% of biogas plants in our sample are technically efficient, 40% are scale efficient and 50% are managerial efficient; ii) small biogas plants (<100 kW) are scale inefficient exhibiting increasing returns to scale; iii) production subsidies show a significant, negative relationship to managerial efficiency. The results are consistent with the hypothesis that production subsidies provide a disincentive to managerial effort of plant operators.

Embodied Energy Calculation of Small-Scale Biogas Plants in Rural Areas of Bangladesh

Installation of a biogas plant consumes a considerable amount of energy especially in transportation and manufacturing of various biogas plant construction materials. Energy conservation has become one of the important issues of today’s world for reducing greenhouse gases emission into the atmosphere and for reducing the costs of materials. This paper is focused on some issues relating to embodied energy in a biogas plant, particularly in the Bangladeshi context. Energy consumption in the production and transportation of basic biogas plant materials (such as brick, cement, sand etc.) and other materials used for construction has been discussed. Data has been collected from 20 small-scale biogas plants (2.4 m 3 , 3.2 m 3 , 4.8 m 3 ) located in different rural areas of Rajshahi, Bangladesh. It is found that the embodied energy of 2.4, 3.2 and 4.8 m 3 biogas plants are 9.4 GJ, 11.4 GJ, and 22.7 GJ respectively. Around 59-63% of total energy is costs by bricks, 29-33% by cement, 1.5% by sand, 3-5% by PVC pipe, 1% by HDPE pipe and 0.5% by steel used to install the plants. It is also found that the energy required for the production of the construction materials was 83-85% of total energy required while transportation energy was 16-17%. However, a complete analysis of energy input for the installation of a small scale biogas plant in Bangladesh has been described in this paper which will hopefully be helpful for further research in this sector.