An agricultural unit and use thereof relates to: a tank system adapted to provide a combined aquatic environment for raising aquatic animals in aquaculture and cultivating plants in hydroponic culture, whereby excretions of the aquatic animals are released directly into the aquatic environment so as to produce nutrients for the plants； and an electrochemical device； wherein the electrochemical device is operable in an electrolysis mode to produce hydrogen and oxygen while consuming electrical energy provided by a source of electrical energy； wherein the electrochemical device is further operable in a fuel cell mode to produce electrical energy and heat by oxidizing the produced hydrogen； and wherein the electrochemical device is operatively coupled to the tank system so as to transfer at least part of the produced heat and the produced oxygen to the aquatic environment.
