HAVANA TIMES, July 11 (IPS) – Some 700 biogas plants operate on state farms and in the private farm sector in Cuba, where this technology is being produced to conserve energy and protect the environment.Biogas is a mixture of methane and carbon dioxide, with small proportions of hydrogen, nitrogen, oxygen and sulfide of hydrogen. The gas is obtained from decomposition in an anaerobic (oxygen free) environment of organic waste, such as animal manure or vegetable waste. It is being used for ligh