Large Scale Biogas

Industrialised countries commonly use biogas digesters where animal dung, and increasingly fuel crops are used as feedstock for large-scale biogas digesters. Brazil and the Philippines lead the world in crop-based digesters using sugar-cane residues as feedstock.  

Interest and public support in biogas has been growing in most of the European countries. After a period of stagnation, caused by technical and economical difficulties, the environmental benefits and increasing price of fossil fuel have improved the competitiveness of biogas as an energy fuel. This has been seen in both small and large scale plants in Denmark, Germany (with over 3000 plants producing 500MW electricity and 1000MW of heat) and Switzerland, and as a transport fuel in Sweden (where vehicles using biomass were voted environmental cars of the year in 2005). 

There have been interesting biogas projects in the UK, Ireland, and the Netherlands. Despite this, the use of biogas in Europe is modest in relation to the raw-material potential, and biogas produces only a very small share of the total energy supply.  Several countries are experimenting with dedicated biogas energy crops, such as newly bred grass varieties (Sudan grass and tropical grass hybrids) or biogas ‘super maize’ developed in France. The crops are developed in such a way that they ferment easily and yield enough gas when used as a single substrate. Biogas crops can be used whole, which allows for the use of far more biomass per hectare.  

When produced on a large scale, biogas can be fed into the electricity grid and enter the energy mix without consumers being aware of the change. A select number of European firms have already begun doing so, while farmers who generate excess biogas on their farms make use of incentives to sell the electricity they generate from it to the main power grid. In Germany, electricity from biogas is an integral part of the energy market. In 2005, biogas units produced 2.9 billion kilowatt-hours of electricity. 

Despite recent economic instability, the construction of larger plants producing gas continues to be highly lucrative for both farmers and financial investors in Germany, with over 30 new plants planned for 2010 (Frost and Sullivan). The German bioenergy company Nawaro Bioenergie AG is completing the world's largest integrated biogas power station in Klarsee, Penkun, in the German state of Mecklenburg-Western Pomerania.

The complex will generate 20 megawatts (MW) of electricity by fermenting energy maize by liquid manure. After fermentation the biomethane is converted by combustion into electricity and heat. The complex utilises 40 Jenbacher Gas Engines that will cogenerate 20 megawatts of electricity and 22 megawatts in thermal output. The first module began operations in November 2006 and now 15 modules are operating. The 20MW output is enough to meet the energy needs of a town of 50,000 people (Biopact). 

Dragon Power Company, China's biggest biogas - biomass energy company (50 power plants) plans to build about 30 biogas power plants by 2010, with an estimated total investment of 1.5 billion euro (Helmut Kaiser Consultancy). 

India is planning to deal with one of its major problems – air pollution from transport, through the use of compressed biogas (CBG). Since over 70% of the world's long-term (2030) growth in demand for automotive fuels will come from rapidly developing countries like India, China and Pakistan biogas is highly relevant.