Biogas System Research Articles

A field‐based study demonstrating the need of holistic management system for household biogas plants in rural India

AbstractIndian household biogas system appears promising to contribute substantially to its commitment to increase the share of renewable energy. There has been a consistent effort to promote the household biogas system by the Government of India. Despite such need and effort, the growth of household biogas system in India is not encouraging. Further, the need for appropriate management services for hassle‐free operation and maintenance of household biogas system is also analyzed based on field survey conducted in three villages. Cow dung is the primary feedstock and its abundant availability results in a higher level of adoption of household biogas plants in one of the villages. Alternative feedstocks can adequately supplement cow dung to support the household biogas system in the remaining two villages. Though the higher capital cost of the biogas system is a distracting factor, biogas as a cooking fuel is cheaper than both LPG and fuelwood while considering long‐term analysis. Thus, the continuation of subsidy on household biogas plant is justified considering the issue of affordability to bear capital cost even though for long‐term use non‐subsidized option is also profitable. The non‐availability of own feedstock is a critical issue which influences the economy of biogas users and hence the motivation. Analysis also revealed that the undesirable performance of household biogas system is mostly linked with the absence of proper diagnosis. Chronical poor performance is attributed to one or more factors related to feedstock, microbial activities, and climatic parameters which remain unknown to the users and lead to their diminishing interest. Technology‐integrated management support is expected to revive the interest in household biogas system in rural India.

Modeling and optimization of PV-diesel-biogas hybrid microgrid energy system for sustainability of electricity in Rural Area

The paper presented a hybrid micro-grid renewable energy of different energy sources to generate uninterrupted electricity for the Agu-Amede village using PV, diesel, biogas, and battery. The system optimization was performed to determine techno-economic analysis and energy generated using HOMER software. The energy generated by the hybrid system was able to meet the demand load of the village at all levels of biomass production with surplus electricity in each case when the production of the biogas system varied between 0.5 tons to 3 tons. At biomass production of 3 tons, the total energy generated demand is 480693 kWh with a surplus of 121762 kWh. Again, the hybrid PV and biogas system generate total energy of 98714 kWh (20.50%) and 381979 kWh (79.50%), respectively. The net present cost (NPC) and cost of energy (COE) of the base case architecture (diesel) measured are $1230000 and $0.267/kWh, respectively. Therefore, between 2.5 tons and 3.0 tons of biomass penetration, the energy production of biogas increased, and the diesel system was removed from the hybrid system setup. This is because the availability of biogas is almost sufficient to meet the load demand at a lower cost and solar PV architecture was added to the hybrid system to balance energy production.

Impact of Varying Mass Concentrations of Ammonia Nitrogen on Biogas Production and System Stability of Anaerobic Fermentation

High ammonium release from chicken manure poses a significant limitation to aerobic digestion, impeding microbial processes and inhibiting biogas production. In this study, we conducted anaerobic digestion of a mixture consisting of chicken manure and corn straw as the fermented raw material. The inoculum used was obtained from the residue of previously fermented chicken manure. To assess the inhibitory effect, we varied the ammonia levels within the range of 750–4250 mg/L by introducing ammonium chloride. The efficiency of aerobic digestion was monitored through the measurement of volatile fatty acids (VFA), chemical oxygen demand (COD), total inorganic carbon (TOC), and methane yield. Our results indicated that elevated levels of ammonia nitrogen had a suppressive impact on methane release, and this decrease followed a linear relationship with the increasing ammonia nitrogen load. Moreover, the addition of ammonia led to a slower release, with the maximum daily ammonia concentration observed at 15 days compared to the 6th day at lower ammonia levels. Furthermore, on the 40th day of aerobic digestion, the cumulative methane production at 4250 mg/L was inhibited by 41% compared to the 750 mg/L condition. The patterns of VFA, inorganic carbon, and COD reduction were consistent across all ammonia levels, with VFA and TOC levels being highest at the highest ammonia concentration and lowest at the lowest ammonia concentration. The accumulation of VFA resulted in a decrease in pH and a decline in methanogenic activity. Additionally, high ammonia levels altered the relative abundance of methanogens. Acetoclastic methanogens (Methanosaeta) exhibited a decrease in abundance, while hydrogenotrophic methanogens (Methanosaeta, Methanoculleus) and methylotrophic methanogens (Candidatus Methanoplasma) demonstrated an increase in abundance. Overall, our findings highlight the inhibitory effects of high ammonia concentrations on biogas production, providing insights into the changes in microbial composition and activity during anaerobic fermentation.

Biogas production from food waste hydrolysate using a subcritical water pretreated process and pulp wastewater seed sludge

This study was investigated the biogas production performance from subcritical water hydrolysate (SCWH) using a pretreated food waste (FW) process, and pulp wastewater (PW) as seed sludge according to different volatile solid (VS) ratio of PW to SCWH, and different substrate concentration. The subcritical water hydrolysis was acted for 30 mins in a 70 ml Teflon reactor under different temperatures varied from 119, 129, 139, 159, and 195 ℃, respectively. A batch system for optimal biogas and methane production yields examination were fermented in a 60 ml flask under 37 °C and 120 rpm. A maximum biogas yield of 807.0 ml/g VSre and methane yield of 329.5 ml/g VSre were achieved at a VS ratio of PW to SCWH 1:3 and substrate concentration of 25 g/L with a hydrolysate under 159 ℃ and the volatile solids (VS) removal efficiency of 80%. These results indicated that the food waste pretreated by subcritical water hydrolysis can efficiently increase the biogas production under optimal conditions.

Novel adaptive power distribution master–slave control strategy for a biogas–solar–wind battery islanded microgrid based on a microturbine

As many countries increase their investment in the field of renewable energy, technological research and development has increased on establishing biogas–solar–wind battery islanded microgrids (BSWBIMs) based on biogas generation technology. In BSWBIMs, multiple distributed generators (DGs) are controlled to share either the lack or surplus of power throughout the microgrid. To improve the reliability and economic efficiency of the system, a reasonable control strategy is indispensable. In this paper, a novel adaptive power distribution master–slave (APD–MS) control strategy is proposed to maintain the system voltage and frequency within the Chinese national grid requirements. Moreover, compared with the conventional master-slave control strategy, the proposed control strategy can solve the problem of high dependence on the master DG. Notably, the proposed control strategy can improve the biogas utilization efficiency, system reliability and system stability. The theoretical analysis and software simulation based on BSWBIMs at low voltage levels demonstrate the effectiveness and superiority of the proposed APD–MS control strategy.

Green Fleet: A Prototype Biogas and Hydrogen Refueling Management System for Private Fleet Stations

Biogas and hydrogen (H2) are breaking through as alternative energy sources in road transport, specifically for heavy-duty vehicles. Until a public network of service stations is deployed for such vehicles, the owners of large fleets will need to build and manage their own refueling facilities. Fleet refueling management and remote monitoring at these sites will become key business needs. This article describes the construction of a prototype system capable of solving those needs. During the design and development process of the prototype, the standard industry protocols involved in these installations have been considered, and the latest expertise in information technology systems has been applied. This prototype has been essential to determine the Strengths, Challenges, Opportunities and Risks (SCOR) of such a system, which is the first step of a more ambitious project. A second stage will involve setting up a pilot study and developing a commercial system that can be widely installed to provide a real solution for the industry.

Techno-Economic Optimization of SOC Design and Operating Conditions in a Solid Oxide Fuel Cell-Gas Turbine Hybrid System

Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid systems can reach exceptionally high fuel-to-electricity conversion efficiencies while emitting virtually zero criteria pollutants. Due to these characteristics and their fuel-flexibility, SOFC-GT hybrid systems are seen as a key technology in sustainable power generation. In this work we explore SOFC cell design parameters that can synergistically reduce thermal stress and cost, as well as system-level design strategies to maximize economic performance. Results show that NG-fueled hybrid systems can reach efficiencies of 75%-LHV at a cost-of-electricity of 77.73 $/MWh. A similar biogas system with integrated anaerobic digester and biogas upgrading resulted in an efficiency of 53%-LHV and a cost-of-electricity of 137.19 $/MWh.

Molecular characterization of Cryptosporidium and Giardia in environmental samples and faecal samples from biogas users in Bac Giang, Vietnam

Little is known about Cryptosporidium and Giardia in biogas waste and humans in Vietnam. There is a potential risk of infections during or after using the biogas system. The detected protozoan genotypes are zoonotic pathogens, and contamination of vegetables may relay through runoff to the surface waters and soil. The objective of this study was to understand the role of the environment in the epidemiology of human infections in Bac Giang province, Vietnam, with a focus on investigating the presence of Cryptosporidium spp. genotypes and Giardia assemblages among 239 environmental samples and 94 faecal samples of biogas users. PCR and sequencing analysis were used to identify the occurrence and genotypes of Cryptosporidium and Giardia in these samples. Results showed that 13/333 (3.9 %) and 9/333 (2.7 %) samples were positive for Cryptosporidium oocyst and Giardia cysts, respectively. Characterization revealed the presence of Cryptosporidium scrofarum, C. suis, C. meleagridis, C. bailey and Giardia intestinalis assemblage A and E. C. scrofarum and Giardia assemblage E were identified for the first time in humans in Bac Giang. The current information from the above investigations will be valuable for protozoan source tracking and control interventions against Cryptosporidium and Giardia infection associated with biogas wastes in Vietnam.

From global climate goals to local practice—mission-oriented policy enactment in three Swedish regions

Abstract As the national and supranational levels of government embrace the concept of missions to solve wicked problems, the importance of understanding how missions move from one level of governance to another becomes essential. In this paper, we present a comparative case analysis of evolving regional biogas systems to consider how global missions on climate action are enacted in local practice. Referring to wickedness in terms of contestation, complexity, and uncertainty of both problems and solutions, we examine how such framings affect the operationalisation of the missions. Our results indicate that in the process of local translation, wickedness often increases, but additional wickedness does not always worsen the outcomes.

An integrated energy recovery system for productive biogas applications: Continuous mode operation and assessment

The application of biogas as a renewable energy source continues to face competition from conventional energy sources, which are readily available and seemingly cheap. In addition, productive biogas system deployments in Uganda are currently facing challenges related to sustainability of biogas production, which has led to massive dis-adoption in recent years. These systems have failed to utilize alternatives during scarcity of primary feedstock due to lack technical data for energy recovery, which could be linked to insufficient R&D in the biogas sector. Relatedly, global scientific research has placed focus mostly on methane yield improvements through optimization of anaerobic digestion kinetics on lab-scale, with little focus on the enabling environment for these kinetics to thrive in continuously operated systems.This study therefore aimed to develop an integrated energy recovery system that enables alteration of feedstock and control of digester operating parameters for sustainable biogas production in continuously fed digesters. An array of system components was developed and integrated into a state-of-art energy recovery system, which was prototyped and deployed in real working environment for pilot studies. The system was configured to measure the moisture content of the feedstock and then determine and display to the operator the amount of water to be added to optimize the quality of the substrate. The system also monitors the digester operating parameters and prompts corrective action to prevent possible inhibition of biogas production process. Results show that the system is about 33% more efficient than the conventional one, allows alteration of feedstocks, and can be deployed to replace conventional energy usage for productive applications. For instance, a poultry farm with 10,000 commercial layers may have its energy needs be met 100% by the proposed system with a pay-back period of 4.5 years for deep liter system and 3.7 years for battery cage system.

Genome-centric metagenomics revealed functional traits in high-solids anaerobic co-digestion of restaurant food waste, household food waste and rice straw

High-solids anaerobic co-digestion (HS-AcoD) of food waste (FW) and other organic wastes is an effective option to improve the biogas production and system stability compared to mono-digestion. However, the clean and sustainable HS-AcoD strategy for FW and associated microbial functional traits have not been well explored. Here, HS-AcoD of restaurant food waste (RFW), household food waste (HFW) and rice straw (RS) were performed. Results showed that the maximum synergy index (SI) of 1.28 were achieved when the volatile solids ratio of RFW, HFW and RS was 0.45:0.45:0.1. HS-AcoD alleviated the acidification process by regulating metabolism associated with hydrolysis and volatile fatty acids formation. The synergistic relationship between syntrophic bacteria and Methanothrix sp., and the enhanced metabolic capacity associated with the acetotrophic and hydrogenotrophic pathways dominated by Methanothrix sp., provided a further explanation of the synergistic mechanism. These findings advance the knowledge about microbial mechanisms underlying the synergistic effect of HS-AcoD.

China’s Biogas Industry’s Sustainable Transition to a Low-Carbon Plan—A Socio-Technical Perspective

China’s biogas industry has experienced ups and downs over the past two decades, with various challenges pointing to misplaced expectations that biogas technology is overly focused on energy production. With the promotion of China’s low-carbon strategy, a more rational and sustainable transformation strategy is crucial for the development of the biogas industry. To elucidate the sustainable development process of the biogas industry, this study applies the socio-technical transition theory and the strategic niche management (SNM) approach to understand the multi-regime interactions of biogas systems and their possible future paths. At present, the Chinese biogas industry needs to abandon the expectation of energy recovery and establish the expectation of multi-functional combination, especially including nutrient cycling. This study proposes a sustainable transformation path for the biogas industry and predicts three phases based on the type of socio-technological transformation path: a transformation path to 2030 to promote niche innovation and develop core technologies; a reconfiguration path from 2030 to 2050, which will require a lot of trials and errors; and the expansion of market share in 2050 through technology replacement. This study highlights the importance of niche experimentations and broad advocacy coalitions for the biogas industry. This research also illustrates how the transformation of China’s biogas industry can be achieved through incremental innovation with consistent policy support.

OWEFE—open modeling framework for integrated water, energy, food, and environment systems

The integrated approach to managing the fundamental resources for human life, namely, water, energy, food, and the environment as their irreplaceable foundation, presents a profound opportunity for sustainable development. However, despite their huge potential, integrated water, energy, food, and environment systems (iWEFEs) are rarely put into practice because of, among others, complexity and a lack of uniform and openly available models to describe, configure and simulate such systems. To fill this gap, we present the open modeling framework for integrated water, energy, food, and environment systems (OWEFEs) based on the open energy modeling framework. OWEFE follows an open, cross-sectoral, and modular design approach to address crucial challenges for the project development of iWEFEs. In this study, we apply OWEFE for the first time to model a wastewater biogas system and an agrivoltaics system. The results of the OWEFE-based models are in the range of a conventional approach respectively of on-site measurements indicating the framework’s capability to model diverse iWEFEs. The wide application of the framework can improve the assessment, planning, and configuration of iWEFEs for sustainable and integrated infrastructure development.

Optimising a Biogas and Photovoltaic Hybrid System for Sustainable Power Supply in Rural Areas

This paper proposes a method for evaluating the optimal configuration of a hybrid system (biomass power plant and photovoltaic plant), which is connected to the electrical grid, to achieve minimum energy costs. The study is applied to a small rural municipality in the Valencian Community, Spain, as an energy community. The approach takes into account the daily energy demand variation and price curves for energy that are either imported or exported to the grid. The optimal configuration is determined by the highest internal rate of return (IRR) over a 12-year period while providing a 20% discount in electricity prices for the energy community. The approach is extrapolated to an annual period using the statistical data of sunny and cloudy days, considering 23.8% of the year as cloudy. The methodology provides a general procedure for hybridising both plants and the grid to meet the energy needs of a small rural population. In the analysed case, an optimal combination of 140 kW of rated power from the biogas generator was found, which is lower than the maximum demand of 366 kW and 80 kW installed power in the photovoltaic plant, resulting in an IRR of 6.13% over 12 years. Sensitivity studies for data variations are also provided.

Anaerobic Co-Digestion of Pig Manure and Rice Straw: Optimization of Process Parameters for Enhancing Biogas Production and System Stability.

The objective of this study was to optimize the process parameters of the anaerobic co-digestion of pig manure and rice straw to maximize methane production and system stability. In this study, batch experiments were conducted with different mixing ratios of pig manure and rice straw (1:0, 1:1, 1:5, 1:10, and 0:1), total solid concentrations (6%, 8%, 10%, 12%, and 14%), and inoculum accounts (5%, 10%, 15%, 20%, and 25%). The results show that a 1:5 mixing ratio of pig manure to rice straw, a 12% total solid content, and a 15% inoculum account yielded biogas up to 553.79 mL/g VS, which was a result of co-digestion increasing the cooperative index (CPI > 1). Likewise, the evolution of the pH and VFAs indicated that the co-digestion system was well-buffered and not easily inhibited by acidification or ammonia nitrogen. Moreover, the results of the Gompertz model's fitting showed that the cumulative methane production, delay period, effective methane production time, and methane production rate under optimal conditions were significantly superior compared to the other groups employed.

Optimization and Analysis of a Low-Pressure Water Scrubbing Biogas Upgrading System via the Taguchi and Response Surface Methodology Approaches

Biogas upgrading is essential in order to increase the calorific value and improve the quality of raw biogas. This present study aims at investigating the optimum performance of a near atmospheric pressure water scrubbing (NAPWS) system for biogas upgrading while using both the adsorption and absorption techniques. This was achieved through a two-stage process: namely, the Taguchi approach followed by the response surface methodology (RSM). The Taguchi orthogonal array design consisted of 27 runs where the raw biogas pressure (10 - 30 kPa), liquid flow rates (2.6 - 4.2 l/ min.) and variations of the steel wool height (0 - 45.72 cm) in the adsorption column were experimentally studied with respect to the methane (CH4) yield and removal efficiency of hydrogen sulfide (H2S) and carbon dioxide (CO2). From the experiments, the removal efficiency of hydrogen sulfide was greater than 87% with the average bio-methane content of 77.67%. During the second-stage, the analysis of variance (ANOVA) and the RSM were undertaken for optimization of the process parameters. The optimum bio-methane concentration of 84.71 (%v/v) CH4 and 13.31 (%v/v) CO2 was attained at gas pressure of 14kPa, liquid flow rate of 4.2 l/min., and steel wool height at 22.86cm obtained through numerical optimization. These results revealed that the utilization of the Taguchi and the RSM yielded to the best optimal system performance with the liquid flow rate as the most significant factor

Development of Balloon Biogas Plant for Small Farmers

Biogas plants are a sustainable and environmentally friendly way of generating energy from organic waste materials such as animal manure, crop residues, and food waste. In addition to producing biogas, these plants also generate nutrient-rich bio-slurry, which can be used as a fertilizer to improve soil fertility and crop yields.The utilization of natural resources for cooking gas generation has been a long-standing practice in various countries. However, the prevalent issue with existing systems lies in their chambers, which are prone to damage due to low-quality materials. Additionally, their construction often requires skilled labor and high-quality materials, posing challenges in affordability and accessibility. A comparison study conducted by referring problems that lead to troubleshooting in Biogas Plants between various types of biogas and a novel balloon-type biogas system has been designed and developed to address these limitations. The system exhibits cost-effectiveness, weather resistance, and thermophilic characteristics, enabling operation at high temperatures of 50°-55°C, within the range suitable for the digestion of mesophilic bacteria (40°-50°C) that contribute to gas generation. The work also elaborated to enhance biogas efficiency by incorporating a scrubber module capable of removing impurities such as hydrogen sulfide (H2S), carbon dioxide (CO2), and water vapor (H2O).

Peternakan Sapi Perah Rendah Emisi Metan : Usulan Pengembangan Badan Usaha Milik Pesantren

<p>The fulfillment of community nutrition, especially the increase in animal protein, can be increased by consuming milk, so there needs to be an increase in national milk production. Increasing national milk production can be done by initiating dairy farming in several areas. Products from dairy farms can be in the form of fresh milk, yogurt, ice cream, and cheese. Dairy farming with low methane emissions is a hope to reduce global warming, so there are several treatments that can be applied, namely the use of tannins, saponins, HMG CoA inhibitors, anthraquinones, nitrates and ration regulation, as well as the application of a biogas system as an alternative energy source.</p>

RENEWABLE ENERGIES IN THE SETTLEMENTS (A STEP TOWARD A CLEAN CITY)

As a result of the energy crisis of fossil fuel in the world, and pollution that comes from using these types of fuels, humans need to find clean and affordable energy to survive, impelling communities which produce their energy to carry out new initiatives. The use of wind, water, earth, solar and other clean energy has become possible, and finally, the world is on a path that requires new research in this field. Between the urban and social elements, per capita energy in the housing sector is allocated the highest consumption in the world, and this sector has the greatest amount of energy consumption in Iran as well. Researchers are presenting new solutions in addition to the usage of technology in the production of renewable energies, making closer to reality the reproducible ideas about using parts of buildings and natural forces around the buildings. This study is an attempt to explore the surrounding natural forces and materials that are used in construction, alongside the study of books and valid and scientific global websites that discussing the idea of using new technologies along with the existing energy production. Using renewable energy, homes have been made from special materials, where the manner of design adjusts to the environment (like solar energy), but can still function in any condition. We have seen that by studying the available information, biogas and photovoltaic systems are also intended to (in addition to their own sufficiency) and lead to saving energy. The day is coming that single municipal buildings will manage to make their fossil energy usage reach zero.

Economic assessment for vegetable waste valorization through the biogas-biomethane chain in Italy with a circular economy approach

The current geo-political framework and the environmental concern about pollution and global warming are leading Europe to rethink its energy production, moving forward to the incentivization the renewable energy market. In this scenario, the use of waste from the agri-food sector shows a huge potentiality to enhance the transition in line with the circular economy principles. Biogas production represents an environmental friendly strategy to successfully recover large amounts of waste and by-products to produce renewable energy. Furthermore, in light of the rising need of green biofuels, biogas can be converted into biomethane, allowing the implementation of a full circular model. The objective of this paper is to perform an economic assessment to evaluate whether the upgrading of an existing biogas plant, in which the diet includes also vegetable waste from a plant producing frozen vegetables, could be profitable considering different scenarios, to reach a sustainable circular model. The analysis will be conducted through the Discounted Cash Flow method, considering four main indexes: NPV, DPBT, IRR, and PI. The results highlight the unprofitability of the biogas-biomethane chain if the upgrading system is performed maintaining the same characteristics of the starting plant. On the other hand, if changes in the digester's diet occur, the investment becomes immediately profitable in the considered time-span. The circular economy model is not completely accomplished, as profitability can only be reached if silage maize is partially kept as feedstock. Moreover, the conversion of the plant is not economically feasible if an adequate subsidy is not provided. The economic assessment of the upgrading system for biogas to biomethane is an essential element to be provided to the agribusiness entrepreneurs, as they need all the relevant economic aspects to decide to invest and adopt this solution to establish an innovative circular business model in agriculture.