Tea is amply consumed worldwide and, depending on its degree of fermentation, can be classified in green, black, or oolong. This natural beverage has a wide variety of properties due to its bioactive components; however, waste produced can impact on the environment. In recent years, the leaves of tea spent have been used with the aim of reducing its ecological impact. Its high content of polyphenols gives it excellent properties to be used as substrate to the application of bioprocesses with the aim of obtaining secondary metabolites; however, one of the most attractive alternatives in the production of new sources of energy such as biogas, which can be obtained in an economical and simple way.