Biogas has the potential to be part of the transition towards a more sustainable energy system. Biogas is a renewable energy source and can play an important role in modern waste management systems. Biogas production can also help recirculate nutrients back to farmland. Besides all this, biogas is a locally produced energy source with the potential to increase global resource efficiency, since it can lead to more value and less waste, as well as decreased negative environmental effects. However, biogas production systems are complex, including different substrates, different applications for biogas and digestate, and different technology solutions for digestion, pre-treatment and for upgrading the raw gas. To increase the development of biogas production systems, knowledge sharing is a key factor. To increase this knowledge sharing, comprehensible analysis and comparisons of biogas production systems are necessary. Thus, studies are needed to verify the resource efficiency of biogas production systems from different perspectives. The aim of this thesis is to perform a systems analysis of biogas production systems and to explore how to analyse and compare biogas production systems. An additional aim is to study biogas production systems from a systems perspective, with a focus on environment, energy and economy. Studying biogas production systems from different system levels, as well as from different approaches, is beneficial because it results in deeper knowledge of biogas systems and greater opportunities to identify synergies. Systems studies of biogas are important, since biogas systems are often complex and integrated with other systems. In this thesis, biogas systems analyses are performed at different levels. In the widest system study, classifications of different biogas plants are analysed and classifications in different European countries are compared, with the prospect of paving the way for a new common classification for biogas plants in Europe. Today, classifications vary between countries, and hence comparisons of plants in different countries are difficult. In the narrowest system study, a new methodology for analysing energy demand at different biogas production plants has been developed. The aim was to develop a methodology that is applicable for all kinds of biogas plants with energy inputs. The methodology describes the process of analysing energy demand and allocating energy to sub-processes and unit processes. Further, an approach for assessing the resource efficiency of different treatment options for organic waste was designed. The approach includes environmental, economic and energy perspectives, and was applied to five different regions with several food manufacturing companies. A study of treatment options for organic waste from a single food company was also conducted. The results showed that biogas production is a resource-efficient way to treat waste from the food industry. The approach enables a wider analysis of biogas systems, and the results from the applications show the complexity of assessing resource efficiency. It is also shown that it is important to understand that the resource efficiency of a system is always in relation to the substituted system. In this thesis, three different approaches to analysing biogas production systems are presented: categorization, resource efficiency analysis and energy demand analysis. These approaches all contribute to the understanding of biogas systems and can help, in different ways, to increase knowledge about biogas systems in the world. If knowledge about different biogas systems can be easily disseminated, more of the unused potential of biogas production may be realized, and hence more fossil fuels can be replaced within the energy system. Biogas har potentialen att vara en del av övergången till ett mer hållbart energisystem. Biogas är en förnybar energikälla som kan spela en viktig roll i moderna avfallshanteringssystem. Produktion av biogas kan även hjälpa till att återcirkulera näringsämnen tillbaka till jordbruksmark. Förutom allt detta är biogas en lokalt producerad energikälla med potential att öka resurseffektiviteten i världen, eftersom det kan leda till ökat värde och mindre avfall samt minskade negativa miljöeffekter. Dock är biogasproduktionssystem komplexa, inklusive exempelvis olika substrat, användning för biogasen och rötresterna, olika tekniska lösningar för rötresterna såväl som förbehandling av substrat och uppgradering av rågas. För att öka utvecklingen av biogasproduktionssystem är kunskapsdelning en nyckelfaktor. För att öka kunskapsdelningen är tydliga analyser och jämförelser av biogasproduktionssystem nödvändiga. Därför behövs studier för att verifiera resurseffektiviteten för biogasproduktionssystem från olika perspektiv. Syftet med denna avhandling är att utföra systemanalyser av biogasproduktionssystem och att undersöka hur man analyserar och jämför biogasproduktionssystem. Vidare är syftet också att studera biogasproduktionssystem ur ett systemperspektiv med fokus på miljö, energi och ekonomi. Det är fördelaktigt att studera biogasproduktionssystem på olika systemnivåer och utifrån olika tillvägagångssätt, eftersom kunskapen om biogassystem fördjupas och möjligheterna att hitta synergier ökar. Systemstudier av biogas är viktigt eftersom biogassystem ofta är komplexa och integrerade i andra system. I denna avhandling utförs analyser på olika nivåer av biogassystemen. På den högsta systemnivån analyseras klassificeringar av olika biogasanläggningar. Klassificeringar i olika europeiska länder jämförs, med förhoppningen att bana väg mot en ny, gemensam klassificering för biogasanläggningar i Europa. Idag varierar klassificeringarna mellan länder och därför är jämförelser av anläggningar mellan länder svåra. På den lägsta systemnivån utvecklades en ny metod för analys av energibehov vid olika biogasproduktionsanläggningar. Syftet var att utveckla en metod för alla typer av biogasanläggningar. Metodiken beskriver processen för att analysera energibehov och fördela energin till delprocesser och enhetsprocesser. Vidare utformades en metod för att bedöma resurseffektiviteten hos olika behandlingsalternativ för organiskt avfall. Metoden inkluderar miljö, ekonomi och energi och tillämpades i fem olika regioner med flera livsmedelsindustriföretag. En studie av behandlingsalternativ för organiskt avfall från ett enda livsmedelsföretag genomfördes också. Resultaten visade att biogasproduktion är ett resurseffektivt sätt att behandla avfall från livsmedelsindustrin. Metoden möjliggör en bredare analys av biogassystem och resultaten från tillämpningarna visar komplexiteten i att utvärdera resurseffektiviteten. Det visas också att det är viktigt att förstå att ett systems resurseffektivitet alltid är i förhållande till det substituerade systemet. I denna avhandling presenteras tre olika metoder för analys av biogasproduktionssystem: kategorisering, resurseffektivitetsanalys och energibehovsanalys. Dessa tillvägagångssätt bidrar alla till att förstå biogassystem och kan på olika sätt bidra till att öka kunskapen för biogassystem i världen. Med bra system för att sprida kunskap om olika biogassystem kan mer av den outnyttjade potentialen för biogasproduktion realiseras och därmed kan fler fossila bränslen i energisystemet ersättas, samtidigt som de övriga fördelarna med biogas också kommer samhället till nytta.

The global demand for energy is met mainly by fossil fuels. Their excessive and indiscriminate use, coupled with increasing demand for energy, will soon deplete their existing reserves. Therefore, it is extremely important to find alternative, environment-friendly, and ecologically sound sources of energy for meeting the present and future energy requirements. Biogas Technology: Towards Sustainable Development makes an attempt to explore the potential of utilizing biodegradable biomass as fuel and manure.

This book presents the state of the art in biogas production using anaerobic digestion technology, with an emphasis on waste utilization/valorization. Offering a comprehensive reference guide to biogas production from different waste streams, it covers various aspects of anaerobic digestion technology from the basics, i.e., microbiological aspects to prominent parameters governing biogas production systems, as well as major principles of their operation, analysis, process control, and troubleshooting. Written and edited by internationally recognized experts in the field of biogas production from both academia and industry, it provides in-depth and cutting-edge information on central developments in the field. In addition, it discusses and reviews major issues affecting biogas production, including the type of feedstock, pretreatment techniques, production systems, design and fabrication of biogas plants, as well as biogas purification and upgrading technologies. ‘Biogas: Fundamentals, Process, and Operation’ also addresses the application of advanced environmental and energy evaluation tools including life cycle assessment (LCA), exergy, techno-economics, and modeling techniques. This book is intended for all researchers, practitioners and students who are interested in the current trends and future prospects of biogas production technologies.

This book focuses on biogas production by anaerobic digestion, which is the most popular bioenergy technology of today. Using anaerobic digestion for the production of biogas is a sustainable approach that simultaneously also allows the treatment of organic waste. The energy contained in the substrate is released in the form of biogas, which can be employed as a renewable fuel in diverse industrial sectors. Although biogas generation is considered an established process, it continues to evolve, e.g. by incorporating modifications and improvements to increase its efficiency and its downstream applications. The chapters of this book review the progress made related to feedstock, system configuration and operational conditions. It also addresses microbial pathways utilized, as well as storage, transportation and usage of biogas. This book is an up-to-date resource for scientists and students working on improving biogas production.

Written as a practical introduction to biogas plant design and operation, this book fills a huge gap by presenting a systematic guide to this emerging technology -- information otherwise only available in poorly intelligible reports by US governmental and other official agencies. The author draws on teaching material from a university course as well as a wide variety of industrial biogas projects he has been involved with, thus combining didactical skill with real-life examples. Alongside biological and technical aspects of biogas generation, this timely work also looks at safety and legal aspects as well as environmental considerations.

This book provides comprehensive and simplified coverage of fundamentals of biogas such as production, purification, storage, methods of improving yield and utilization, types, construction, design and operation of biogas plants. It covers stepwise design and a manual for construction of biogas plants including a planning guide, profitability analysis and evaluation of biogas plants. The biogas energy profile in Nigeria is exclusively covered. Features: Explores planning for biogas plants as a pre-requisite to develop a functional plant balancing energy production and consumption. Gives out detailed provision of the types of substances that are and can be used for biogas production covering animal, municipal, and industrial wastes. Provides knowledge for aspiring biogas producers as well as decision makers, specifically in the context of Nigeria. Covers use of digestrate for anaerobic digestion as a waste treatment method and on the input (feedstock) to the biogas plant. Compares carbon dioxide emissions from biogas plants with fossil fuel plants. This book aims at Graduate Students and Researchers in Agricultural, Environmental, Chemical, Civil and Energy engineering and related professional audience.

In recent years, the importance of biogas energy has risen manifold and has become universal. This is due to the realization that biogas capture and utilization has great potential in controlling global warming. By capturing biogas wherever it is formed, we not only tap a source of clean energy, but we also prevent the escape of methane to the atmosphere. Given that methane has 25 times greater global warming potential than CO2, methane capture through biogas energy in this manner can contribute substantially towards global warming control.