The biogas handbook: Science, production and applications

Biogas is formed naturally from biogenic matter, indeed all forms of biomass, under anaerobic conditions. This naturally occurring biogas escapes into the atmosphere where its main component, methane, is a significant contributor to global warming. Over the last century, methane has become one of the most used fuels for power generation, heating and transportation purposes. While the vast majority of methane used in society today comes in the form of natural gas, there is rapidly growing interest in capturing the methane formed from decaying biomass. This, of course, does not mean capturing the methane released from all the natural sources in nature. It means setting up dedicated biogas facilities where the biogas process can be fully contained, controlled and optimised and a commercially viable industry can be established, harnessing nature’s potential to produce renewable, environmentally sustainable, gaseous biofuel. Biogas has been used in household and farm-scale applications for many years. Biogas (or sewage gas) production has been a standard process since the 1930s for the stabilisation of sewage sludge. What has changed over the last 40 years or so is that biogas production has been achieved on a more industrial scale, with a higher efficiency, degree of complexity and specification, particularly in Europe and in North America. Since the start of the twenty first century, policy makers have recognised the fact the biogas production can answer a number of challenges simultaneously. It can reduce emissions of greenhouse gases (GHGs) such as methane (for example from slurry storage), it can provide a renewable source of energy (for renewable electricity, heat or transport) and it can lead to reduced impacts of pollution by waste disposal. Equally important, the process upgrades the waste into a product and makes it a valuable organic fertiliser, thus closing the cycle from soil to crop, to product, to waste and back to the soil. This recognition has led to rapid growth of the biogas sector over the last two decades, which has been promoted through legislation with various targets set worldwide for renewable energy and reduced GHG emissions. The biogas handbook is targeted at a range of readers. It aims to provide detailed information on the whole biogas process chain and thereby to be a sound basis for readers with at least a basic understanding of science or engineering who want to become knowledgeable in the field of biogas. The level is aimed at degree and masters level students, project planners, policy makers and regulators. As a handbook, it contains a breadth and depth of knowledge on biogas processes but can also be considered as a starting point in a detailed study or project and a point of access to a wide range of further expert sources of information. Many references are given for further reading for those needing to go deeper into a particular subject. The individual chapters have been written by the best known experts in the respective fields. The book considers all aspects in the chain from the origin of the biomass feedstocks, feedstock selection and preparation, the anaerobic digestion process, biogas plant equipment design and operation, through to utilisation of the biogas for energy production and the residue, the digestate, which can be used as a biofertiliser. Biogas utilisation is addressed with respect to combined heat and power and upgrading to natural gas equivalent biomethane for transport applications and injection into the natural gas grid. The book also addresses environmental impacts and commercial market applications such as trading of green certificates.JRC.F.8-Sustainable Transpor