A Study of Challenges and Techno-Economic Assessment of Biogas Plants

Abstract

A promising sustainable method for generating energy from municipal, industrial, and animal wastes is biogas. The development of biogas can be combined with plans to enhance sanitation, lessen indoor air pollution, and cut greenhouse gas emissions. In addition to providing a techno-economic feasibility analysis of biogas plants, this research intends to identify technical and non-technological constraints preventing the widespread use of biogas in India. Different waste, renewable energy, and urban regulations have an impact on the distribution of biogas. Therefore, specific obstacles to India\'s current rural and urban biogas systems were identified. The findings demonstrate that there are significant differences in the nature and significance of obstacles amongst biogas systems due to variations in technological maturity, feedstock quality and availability, supply chain, awareness level, and policy support. The developed excel model also provides a full perspective of the economic factors used to assess the viability of a biogas plant project. Users may assess numerous situations and decide on the best course of action for their investment in the biogas sector by using a comparison and analysis technique.

Introduction

I. INTRODUCTION

Biogas may play a role in the shift to a more environmentally friendly energy system. Modern waste management systems may benefit from the use of biogas, a sustainable energy source. Producing biogas can also aid in returning nutrients to crops. In addition to all of this, biogas is a locally generated energy source that has the potential to boost the efficiency of the use of global resources since it may result in increased value and decreased waste, as well as reduced adverse environmental consequences. Nevertheless, biogas production systems are complicated due to the variety of substrates, uses for digestate and biogas, and technological approaches for digestion, pre-treatment, and upgrading raw gas. There is a growing amount of energy demand in India from many industries. Biomass, which is one of the main energy sources in rural India and makes up around 75% of total energy consumption, is currently the new prospect in national programmes for a competitive energy source [1,2].

Due to its ecological sustainability and great efficiency, bioenergy, a major renewable energy source, is crucial in lowering carbon emissions [3]. Bioenergy differs from other renewable energy sources in several ways. As long as the utilization rate is lower than the growth rate, there are significant amounts of biomass feedstock that are available and stored on Earth. As a result, biomass may end up being the only organic resource that is renewable for making energy [4]. The carbon dioxide emissions from using bioproducts can also be countered by the carbon dioxide fixation and absorption from the regeneration of biomass resources since biomass is a biological substance obtained from living or recently lived organisms. Therefore, biomass utilization can realize carbon neutrality goals [5]. In addition, bioenergy can be converted into various types of energy carriers, such as biodiesel, biogas, and bioethanol, which could facilitate easier storage and utilization of such energy [6,7]. Thereby, biomass utilization follows the “waste-to-energy” model and is beneficial for establishing a sound material-cycle society.

Individual homes often operate small-scale plants to produce energy for self-use. On the other hand, large-scale biogas facilities that can produce more than 5000 m3 of biogas per day mostly use municipal sewage organic wastes to produce biogas, which may then be used to generate electricity, heat homes and businesses, and power vehicles. Large-scale commercial biogas plants are managed by entirely private or public-private partnerships to yield financial benefits through the sale of end products such as electricity, transport fuel, or heat. Family-type biogas plants are managed by individual households and require financial investment while only yielding non-monetary benefits, such as biogas used as a cooking fuel instead of gathered fuelwood. 

Uncontrolled urbanization and the rapid pace of population expansion have seriously complicated the challenge of disposing of solid garbage. Food waste makes up a significant component of municipal solid wastes (MSWs), which are frequently dumped in landfills or other places and cause environmental issues, according to a study conducted by Baawain et al. [20]. However, because landfilling produces leachate, methane, and carbon dioxide as well as other annoyances like insects, odor, and vermin like birds and rats, it is expensive, takes up a lot of areas, and may have a severe influence on the environment if improperly managed.

Along with the release of methane, a strong greenhouse gas with a short-term global warming potential 84 times greater than carbon dioxide, leachate might potentially damage soil and subsurface water [21,22,23].

Knowledge exchange is a crucial component in the growth of biogas-producing systems. Clear analyses and comparisons of biogas-producing systems are required to promote this information exchange. Therefore, research is required to confirm the resource productivity of biogas production environments from many angles. The purpose of this project is to identify and assess technical and economic barriers to biogas production to develop capital and operational cost profile and estimate the potential economic feasibility of the biogas production process for achieving its commercial viability.

While there have been some studies concentrating on biogas in particular locations and hurdles to renewable energy in general, there is a dearth of information on the full scope of these barriers and the techno-economic viability of commercializing biogas energy. This initiative intends to close this gap and act as a roadmap for those making investment and adoption decisions in biogas energy.

II. LITERATURE REVIEW

In addition to producing energy and manure, the anaerobic digestion of biodegradable organic wastes has several positive social and environmental effects. The release of local air pollutants like dioxins and furans, as well as methane, a powerful greenhouse gas, are all negative externalities linked to organic wastes that biogas helps to mitigate [8,9].

One of the most popular methods for handling organic municipal solid waste (MSW) is anaerobic digestion (AD), which may produce biogas and methane as alternatives to natural gas and liquid petroleum gas (LPG). After the AD process is complete, the residue is a stabilized organic substance that may be used immediately on agricultural land as a bio-fertilizer (without ripening beforehand). This can replace synthetic or mineral fertilizers and provide the opportunity for nutrient recycling (nitrogen and phosphorus). Consequently, AD of bio waste combines energy generation with advantages for the environment.

The efficiency of AD throughout the biodegradation process, which improves while running at peak performance, is crucial to the generation of biogas. Temperature, organic loading rate, pre-treatment, inoculum, feeding pattern, hydraulic retention duration, and pH are significant parameters that affect biogas generation and have a significant impact on the AD process [19]. As biogas is created by four categories of microorganisms—fermentative, syntrophic, acetogenic, and methanogenic bacteria the microbial population and type of microbes have a major impact on AD and the composition of the gas [24,25].

These bacteria often exist in the natural environment and serve various functions in the anaerobic decomposition of garbage. Different varieties of microorganisms require various environmental conditions to exist. A kind of organism known as mesophilic bacteria thrives at temperatures between 20 and 45 °C, with 35 °C being the ideal temperature [27]. Thermophilic conditions typically occur between 50 and 65 °C, with 55 °C being ideal [28]. In contrast, thermophilic bacteria are a kind of organism that thrives and lives best in relatively hot temperatures (temperature range 41-122 °C). Microorganisms are essential to the breakdown of organic compounds and are crucial to the anaerobic degradation process [29]. Mesophilic AD is more stable than thermophilic digestion, according to the volumetric quantity of biogas generated in various digesters during the digestion process [30].

The use of biogas for energy production, power generation, and transportation in underdeveloped nations still requires improvement on all scales, from small-scale (home or domestic implementation) to large-scale implementation. For biogas to be used to its full potential in underdeveloped nations, there are issues with legislation, money, technical services, sustainability, awareness, and education [10].

There have been initiatives to advance biogas technology since the 1970s. The first oil crisis in the early 1970s showed Indian officials that commercial energy would continue to be out of the financial grasp of the poor in both the rural and urban areas [11]. India imported more oil products than it exported. In addition to increasing the pressure on the national budget to pay for rising energy subsidies for domestic fuels, especially kerosene, used by the rural and urban poor for very basic cooking and lighting needs, the combination of the global energy crisis and local energy shortages increased the risk to the country's energy security.

Based on the review, it was found that barriers differ in different regions depending on the degree of market maturity and availability of natural resources like biomass, land, and water. Barriers such as low ambient temperature and water unavailability in arid regions are area specific whereas others are specific to technological scale like lack of distribution infrastructure hindering the biogas expansion in a centralized system [31,32]. Socio-cultural barriers like objections toward using animal and human waste as raw materials are very specific to the local values and culture [33]. 

Cooking, lighting, and power production using clean fuels like biogas instead of fossil fuels and untreated conventional solid biomass would also assist reduce GHG emissions and indoor air pollution [12]. Numerous research has been done to evaluate technical advancements that increase biomass output, including physiochemical (extraction, carbonization), thermochemical (gasification, pyrolysis), and biochemical (anaerobic digestion) technologies [13,14].

In terms of techno-economic factors, such as energy usage, efficacy, and cost [15], Kamusoko et al. (2019) examined the effectiveness of biological, chemical, physical, and combination pre-treatments in enhancing biomethane synthesis from agricultural wastes. Additionally, Tabatabaei et al. 2020a and 2020b thoroughly assessed biological advancements and improvements in biogas production from three perspectives: upstream, mainstream, and downstream techniques, respectively [16].

The development of the biogas industry is influenced by a wide range of political, economic, and social variables, including regulations in the areas of energy, the environment, agriculture, banking, and education, among others. Both effective coordination between the decision-makers from the aforementioned domains and active participation of the professionals and associations of profile in the process of policy creation is necessary for the growth of this relatively new economic sector [26].

III. METHODOLOGY

The literature research is provided by the co-digestion economic analysis tool to prepare the MS Excel model for the techno-economic feasibility assessment. It was produced by the US Environmental Protection Agency. It is intended for those in decision-making positions who have technical expertise in anaerobic digestion, such as municipal managers, engineers, and anaerobic digestion system operators. Users can use it to assess the advantages and disadvantages of accepting and processing food waste, fats, oils, and greases (FOG), or other organic resources. It makes use of information and certain parameters from the institution being assessed. The application produces economic and operational statistics to help customers better understand the effects and costs of digesting various types of feedstocks at their plant. The data contains:

1. Fixed and recurring costs
2. Solid waste diversion savings
3. Capital investments
4. Biogas production and associated energy value

The challenges preventing the widespread distribution of biogas on a big scale in urban India have been studied. In-depth interviews with chosen stakeholders were thus performed in addition to the literature research to get the knowledge necessary to comprehend the underlying causes of each obstacle, particularly about the distribution of biogas in urban areas. Based on the total literature analysis, open-ended questions on hurdles and biogas policy were posed in a hierarchical order.

For the interviews, consultants and academics active in biogas projects of various sizes were chosen to better understand the main technological and market-related hurdles that exist in India. To further understand the existing policy environment and degree of cooperation between the national and subnational governments, officials participating in biogas policy-making processes at the national, state, and municipal levels of government were interviewed. Policymakers at the state and municipal levels in Gujarat were chosen for the interviews since this state was the first in India to declare a waste-to-energy program.

A qualitative and systemic approach was used to identify barriers to biogas penetration in India. The following steps were taken to extract the relevant literature. The penetration of biogas in India has been hindered, and this was determined using a qualitative and systematic method. The relevant literature was extracted using the procedures listed below.

a. First, a thorough search of research and review publications in the ASCE Library and Scopus database was done.

b. In addition to the literature study, interviews with specific stakeholders were performed to get the knowledge necessary to comprehend the underlying causes of each obstacle, particularly concerning the spread of biogas in India.

c. Conclusions on the difficulties with producing biogas in India were made based on the aforementioned processes.

d. Second, a review of previous studies and reference models was conducted to create an MS Excel model for the Techno-Feasibility analysis of biogas plants.

e. The developed excel model will next be verified using information gathered from prior literature reviews or a case study of a biogas plant.

IV. RESULT AND DISCUSSION

The level of technological advancement in the biogas industry varies greatly from one region to another and is influenced by a variety of variables, including the economic development of the nation, access to technology, the type and availability of feedstock, the need for the implementation of biogas technology, the education level of the populace, and their environmental awareness. As a result, depending on the market's level of development, different hurdles to the implementation of biogas projects may exist. While in moderate and immature markets, the main obstacles relate to the existence, stability, and dependability of the legal framework and support schemes, access to finance, absence of long-term strategies, lack of training, and lack of educational support, the main obstacles in mature markets relate to the availability of feedstock, public perception, indirect land use change (ILUC), and sustainability issues [17, 18].

An excel model is created for the Techno-Economic Feasibility evaluation of biogas facilities, and it is discussed in this part. The Model offers a preliminary assessment of the physical and economic viability of biomass digestion for biogas generation. Because of the model's adaptability, users may change the costs and assumptions to suit their needs. For additional investigation and review, source data is offered wherever it is accessible.

Excel worksheets flow:

1. Overview

2. User Inputs

3. Feedstock parameter

4. Food Waste Feedstock Data

5. Transportation & processing

6. Financial Model Output

7. Summary

A. Component: Overview (Sheet 1)

As shown in Fig. 4, a summary of the model is provided in this part to help new users understand its components, outputs, results, model design, and the types of organic waste it takes into account.

B. Component: User Inputs (Sheet 2)

The calculations generated by the Model as a consequence of the inputs on this page are relevant to your city or organization. The worksheet titled "1-Page Summary" contains the final results. The Model may also be used to compare the outcomes of various strategies and simulate "what if" scenarios.

The three alternatives the model offers for predicting the feedstock data from food waste are shown in Fig. 5.

1. Option 1: Source Type for Food Waste
2. Option 2: Creating Establishments
3. Option 3 - Custom Feedstock Audit (User may directly input the amount of total feedstock in tonnes/day)

The model will produce the predicted data when the user selects just one of these alternatives based on personal preferences.

The sheet "Food Waste Feedstock Data" supports the food waste feedstock estimates for Option 1 and Option 2. If you have more specific information, you can input it directly into the "Feedstock Parameters" worksheet.

Fig. 18 presents a financial summary. It contains all the information necessary for the user to make an investment choice, including digester costing, feedback collection system costs, total project costs, and net present values.

By contrasting the net yearly value of the present process with that of the future process with various biogas usage possibilities, it is possible to ascertain whether the economics of accepting external feedstocks is a worthwhile investment. While this is the major outcome, further inferences from the model can be made through comparative analysis.

Analyze how your present process will be affected by modifying the biosolids handling parameters. Other outcomes might be inferred from the model's output; this is not an exhaustive list.

Conclusion

Particularly in small towns, a sizable amount of garbage is made up of biomass wastes. Thus, it is crucial to use biomass waste as a recyclable resource to advance a society that values cycles. There are several known methods for using biomass wastes, including composting, making biogas, and generating energy. Several policy proposals are made for removing these barriers in light of our findings. The majority of the population in rural regions lives in low- and middle-income families, creating a higher demand for clean, inexpensive energy. The upfront installation cost of the biogas plant is the main impediment to the deployment of rural biogas plants among these families. This project\'s main finding is: 1) The limited adoption of biogas technology in India is the consequence of several financial and nonfinancial hurdles that also differ from region to region and from urban to rural regions. 2) This project can serve as a manual for new entrants in the biogas business by combining information about difficulties encountered in biogas generation with the use of the provided Excel model. 3) The model was created to offer a method for determining if building a biogas plant would be economically feasible. It is adaptable to make it simple for the user to input personalized data and assess the outcomes. To help reduce the variations in feedstock quality, which could eventually lead to the standardization of technologies for a certain quality and composition of the waste, proper regulations regarding the segregation of organic and inorganic wastes should be enforced on the generators in the long term.

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Copyright © 2022 Jaynil Atodaria . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.