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1.1 Historical background In a historical perspective, biogas has been produced since the second half of the 19th century. India and China were among the pioneering countries, where biogas produced from manure and kitchen waste for long time has been used as a fuel for gas cookers and lamps. In Sweden, biogas has been produced at municipal waste water treatment plants since the 1960’s. The primary incentive was to reduce sludge volumes. However, the oil crises of the 1970’s rang alarm bells, leading to research and development of biogas techniques, and construction of new plants in order to reduce environmental problems and dependency on oil. (Swedish Biogas Association, 2004)

Environmental Technology Assessment of Natural Gas Compared to Biogas