**1. Introduction**

Anaerobic digestion is an attractive biomass-to-energy and waste management technology due to the significant presence of feedstock in form of the organic wastes, food wastes and energy crops, and technology maturity [1]. Biogas is an important renewable energy resource whose production and use can aid in the mitigation of greenhouse gas (GHG) emissions by substituting fossil fuels and promoting the

utilization of biodegradable plant and animal waste feedstocks [2, 3]. With the expected depletion of coal, gas, and oil within the next decade and a half, renewable energy sources like biogas are becoming increasingly important [4]. Another motivation for the use of biogas as an energy resource is the international treaties or agreements that commit countries to reduce their carbon footprint like agenda 21 and Kyoto Protocol [5, 6]. These mechanisms advocated for the transition to renewable and low-carbon sources of energy to reduce global greenhouse gas emissions, particularly from the energy sector which is dominated by fossil fuel sources of energy [7, 8].

Biogas is a viable option to the worldwide energy dilemma and has enormous promise as a sustainable and renewable energy source for commercial, industrial, and residential use [9, 10]. Because of rising environmental concerns and measures in response to concerns over greenhouse gas emissions and climate change, there has been growth in interest in using biomass resources as a renewable feedstock for electricity generation, fuel production, chemical processing, and hydrogen production [11, 12], resulting in increasing energy generation from organic waste production as it reduces the threat to climate change [13]. Electricity generation, thermal applications like cooking, heating, and lighting, and biofuel production are the primary uses for biogas. Biogas is used to produce over 7000 megawatts (MW) of electricity annually [14, 15].

Many developing countries still face the challenge of providing modern energy services to their populations e.g., India alone has about 450 million people with no access to modern energy for electricity [16, 17], yet they have huge biomass resources [18]. There is substantial potential for biomass to play a leading role in global energy generation is evidenced by the 9.7% annual growth rate of biofuels since 1990 [19, 20]. In this context, the role of biogas energy within this huge biomass supply chain cannot be overemphasized. Beyond providing food for all of humanity, agriculture is the primary source of income for more than two-thirds of the world's population. Additionally, bout 82% of the global population is directly or indirectly involved in smallholder agriculture and other industries, making this economic activity the mainstay of many countries [16, 21]. This shows that biogas is important as a renewable and sustainable energy resource for the energy transition and that agriculture and other carbon transformative processes should boost its production and consumption [22, 23].

Biogas has a significant role to play in the ongoing energy transition as a renewable and sustainable energy resource because of its high energy conversion potential and the widespread availability for power generation, industrial applications as a renewable process feedstock and for thermal energy applications [24–28]. Besides biogas production, the anaerobic digestion (AD) process can act as a waste treatment and disposal method while the digestate produced is a valuable organic fertilizer that can replace chemical fertilizers in sustainable agriculture [29, 30]. Anaerobic digestion is an important process in global carbon cycle which produces biogas through biodegradation of organic matter that releases 590–800 million tons of methane into the atmosphere annually which can be mitigated through controlled anaerobic digestion that produces useful biogas [25, 31, 32]. Numerous different organic feedstocks are anaerobically digested to produce biogas, which can then be upgraded to produce biomethane which is an important substitute of natural gas. The sustainable technique of turning biomass waste into biogas can lead to advantages including less carbon emissions, improved organic waste management, and increased resource use efficiency [25, 32].

#### *Biogas Production and Process Control Improvements DOI: http://dx.doi.org/10.5772/intechopen.113061*

Biogas has the potential to contribute to sustainable fuel for multiple applications as a fuel characterized by a high methane content, which is generated through the process of anaerobic digestion of organic substrate under carefully regulated biochemical process conditions [33, 34]. Indigestible carbohydrates, proteins, and lipids are not present in the biomass substrate utilized for biogas production, which can complicate or slow down the digestion [35, 36]. Biogas can also be used as a feedstock for production of biomethane, carbon dioxide, hydrogen, and various biofuels for a wide range of applications including generation of heat and power and feedstock for various industrial processes [20, 37].

In the period preceding the 1800s, man predominantly relied on biomass as its primary source of energy [38, 39]. With the beginning of the industrial revolution, the energy landscape underwent a significant change that was typified by a predominate reliance on fossil fuels, mainly coal, and later petroleum derivatives like natural gas and diesel. A major increase in oil prices was present between the early 1970s to the late 1980s. This situation made it necessary to investigate and promote ecologically friendly, sustainable, and renewable energy sources. During this time, biogas became one of the most popular choices [40–42]. According to [43], in order to mitigate environmental degradation and reduce greenhouse gas emissions, it is imperative to engage in environmental conservation practices and adopt proper waste management strategies. Rural communities, comprising a significant proportion of the populace in numerous developing countries and primarily involved in subsistence agriculture, possess the capacity to generate biogas like in India, where approximately 70% of the populace resides in rural regions [17, 44], whereas on a global average basis, the enormous energy potential of biogas is largely unrealized. A sizeable section of the population works in small-scale agriculture in rural areas of many developing countries. These people have the opportunity to use biogas technology to meet a significant amount of their energy needs [45, 46].

There is considerable potential of biogas as a sustainable energy source, both currently and in the foreseeable future, is significant. Despite the significant potential of biogas to make a substantial contribution to the achievement of sustainable development goals and the global transition toward sustainable energy due to its minimal greenhouse gas emissions, widespread availability, and access to raw materials, its incorporation into the global energy and electricity mix has been constrained [20, 44]. Therefore, it is crucial to initiate a change in the current circumstances [7, 47–49]. The overall objective of this study is to investigate the technological progress and possible uses of biogas in promoting a sustainable worldwide transition and attaining the targets specified in the sustainable development goals. The primary objective of this study is to evaluate the feasibility of incorporating biogas into the existing power grid and other energy applications as a means of reducing emissions. Furthermore, this study presents a comprehensive strategy for the transformation of biogas into electrical energy within the context of a large-scale energy transition. This measure will contribute to mitigating the dual challenge presented by the increasing levels of greenhouse gas emissions and the consequent climate change, in accordance with the emissions and climate goals outlined in the Paris Agreement. This research investigates and evaluates different alternatives, approaches, and feasible technologies to produce electricity using biogas, with a specific emphasis on its implementation in agricultural and industrial contexts. This chapter provides discussion on the potential, prerequisites, and obstacles linked to the production of biogas and the processes to improvement. Furthermore, this study offers an examination

of the biogas potentials that can be employed for the purpose of generating heat and electricity [31, 41, 42, 46, 50].

#### **1.1 Problem statement**

The heightening need for food and energy resulting from the growth of the global population, particularly in developing countries, has intensified the strain on energy production and consumption. This strain is currently associated with the release of greenhouse gases and the subsequent impact on climate change [16]. Although biogas has a great deal of promise to supply clean energy to both rural and urban populations, the prevalence of inoperable and abandoned biogas facilities has raised concerns about the sustainability of the technology. This poses questions concerning the dependable creation, distribution, and use of biogas fuel [17]. It is technically possible to convert this waste into valuable energy sources, thereby generating additional revenue [34, 51, 52].

Sustainable electricity generation is crucial. Hence, sustainable farm-level biogas electricity generation requires appropriate infrastructure design and selection due to susceptibility to biogas system failures [53, 54]. Another thing to consider in such system design is the natural decomposition of agricultural waste that results in the emission of substantial amounts of methane, a potent greenhouse gas, into the atmosphere. Take for instance, in the year 2015, the exclusive contribution of livestock manure to methane emissions in the United States of America amounted to approximately 10%. However, a mere 3% of the total livestock waste underwent recycling via anaerobic digestion [34]. This presents the main issue in utilizing as it lies in its unsteady production value and variations in quality. These factors can potentially disrupt the generation process or hinder the effectiveness of biogas applications, resulting in reduced reliability [55].

This study presents the biogas production, process improvements parameters, and its contribution toward promoting sustainable energy generation for local applications, such as in agriculture, as well as its potential for facilitating the transition of grid electricity toward renewable energy sources. This study focuses on the examination of optimal and sustainable methods for producing biogas. It also proposes sustainable approaches for generating electricity from biogas and producing biofuels such as biohydrogen, methanol, and syngas [42, 56, 57].

#### **1.2 Rationale of biogas production**

The main challenges facing biogas production and use as an energy resource include high equipment cost and a lack of governmental incentive programs in many countries, low reliability or lack of guarantee of long term performance of biogas plants due to technological challenges, unpredictable investment environment, limited biogas distribution and storage capacity for some countries like Sweden and low cost of commercial fertilizers as well as low cost of fossil fuels like gas and oil in some countries [58]. A study by Huang et al. [2] on household biogas digester use in rural China showed that there was rapid growth in the early part of the century in the use of household biogas digesters but the operations were never smooth because out of 1743 households interviewed, 42% adopted household biogas digesters, but on average they worked for just 6.66 months each year which is an indicator of underutilization of the digestors.

Both developed and developing countries face challenges with the utilization of significant organic waste and pressure to replace fossil energy resources like natural

#### *Biogas Production and Process Control Improvements DOI: http://dx.doi.org/10.5772/intechopen.113061*

gas, oil, and coal with renewable energy sources. Anaerobic digestion of organic biomass is now a mature technology while biogas in its raw form or cleaned and upgraded forms have multiple applications as a bioenergy substitute of fossil fuel sources. The production and utilization of biogas have also been growing with capacity growing by more than double between 2009 and 2022 [59]. Methane fermentation occurs naturally in the process of organic matter decay in oxygen-deficient environments like swamps and in landfills leading to the natural emission of methane to the atmosphere as a greenhouse gas. Controlled biogas production can be used to reduce these natural emissions [21, 60].

The human population is steadily growing leading to increased demand for food and energy which simultaneously aggravates the environmental challenges. Substituting fossil fuels with renewable energy alternatives is currently a major global issue of the 21st century and is a key sustainable development objective. Implementation of biogas technologies will significantly transform costly, socially sensitive issues and environmentally damaging fossil fuel dependence, environmental pollution, GHG emissions, and waste conversion into profitable options like electricity generation, heat production and production of biofertilizers. As well as the provision of green vehicular fuel substitute of fossil gas. A national biogas production development program can significantly lead to development of new enterprises, boost income for rural communities and create new jobs to improve people's socioeconomic wellbeing [59].

The implementation of biogas technology enables the harnessing of renewable energy through the utilization of crop and animal waste. The energy source exhibits significant potential for utilization in electricity generation and as a viable thermal energy solution for residential structures. The ultimate outcome of this process can be efficiently harnessed as a valuable fertilizer in rural agricultural environments and households, leading to a reduction in costs related to waste management and disposal [43]. Biogas energy can improve rural people's lives and economies. Many small-holder farmers in developing nations burn biomass for disposal, even though it can be used as a fertilizer, and with biogas technology, an impoverished organic fertilizer that are more affordable can be made by smallholder farmers [61]. Designing biogas systems so that they can reliably supply most or 100% of their energy demands requires defining a number of factors [45]. The challenges limiting full use of biogas that should be overcome, include lack of national generating technologies, need to clean biogas before use, the challenge economic feasibility that requires incentives, the lack penalties for possible environmental damages from biogas schemes [58, 62].
