Biogas an all-rounder

Biogas: a Multitasking Energy Source

Foreword by Arthur Wellinger, President of the European Biogas Association

To date, biogas is the only renewable energy source that is fully established technologically, producing heat, steam, electricity and vehicle fuel. It is, in the true sense of the word, a multitasking energy source. At the same time, it is a decentralised energy vector and an energy carrier that can be made available throughout Europe thanks to injection into and distribution via the natural gas grid.

Biogas has become a real success story over the last 20 years. Roughly 6,000 biogas plants in agriculture and industry are in operation in Europe, of which 5,000 are located in Germany alone. This success is due to the high feed-in tariffs which have been in force over a decade now. More than 20 countries worldwide have copied this model though their approaches have not been as consistent as that of the German government. However, some other countries such as Austria or Denmark are almost equally advanced in terms of the total number of plants relative to inhabitants.

There is a great number of organic substrates from which biogas can be produced. The most widespread substrates in Germany – the leading country in biogas production – is agricultural waste followed by energy crops (maize). In other countries such as Switzerland, Sweden and France, the major source of biogas is separated waste either from households, restaurants and canteens or from para-agricultural industries such as food factories, distilleries, etc.

Until a few years ago the decentralised production of electricity and heat was the only application of biogas. However, most often the heat produced in the combined heat and power system (CHP) could only be used to a very small extent to heat up the digester and the farm dwelling in the winter. Today there is a much greater variety of utilisation options. Thanks to the fact that upgraded biogas can be fed into the gas grid, it can be used in CHPs in urban areas where the heat is used all year round. Once in the grid, biogas can be used for all applications designed for natural gas. The most interesting option is its utilisation as vehicle fuel in public buses and taxis, trucks and passenger cars. It serves as a useful complement to natural gas, reducing CO₂ and NOx emissions as well as particles.

In the field of vehicle fuel, Sweden and Switzerland have the longest tradition and experience, but countries such as Germany, the Netherlands and the UK have been picking up speed in terms of development.

Treating biogas as an energy source alone does not do justice to its overall value. If the substrate is properly selected, the digestate serves as an excellent fertiliser of high quality replacing artificial fertiliser and in particular phosphate which faces depletion within the next 30 to 50 years.

Germany has demonstrated that technology can be a major driving force in the creation of jobs (about 20,000 in Europe) and improving the trade balance. In Germany alone, about two percent of all electricity is produced from biogas, which forms an important part of a total of 12% derived from renewable energy. However, the potential is much bigger. Based on figures of the German Biomass Research Centre (DBFZ), the European Biogas Association (EBA) has calculated that about 3 to 4% of the current vehicle fuel could be covered by biomethane from anaerobic digestion. If combined with biomethane from gasification, it could cover up to 8% of the transport fuel.

Where there is light, there is shadow. We cannot deny that biogas production also faces challenges. One is the unsatisfactory heat utilisation. The recent National Renewable Energy Action Plans have shown that in best case scenarios, only one fifth of the potential heat will be used. Other challenges are the influence of land use and its change on CO₂ emissions and the discussion on food or fuel.

In both cases the hype has passed and discussions have calmed down since more recent data have shown that the influence of land use change has been strongly overestimated and the implementation of best practices in agriculture will help to overcome the remaining increase. Also it has been recognised that land use change is not a problem of energy crops alone – which cover less than 2% of the agricultural land worldwide – but also applies to food production.

Yours,

Arthur Wellinger