Abstract <p>The paper presents a new type of alternative green energy processes and a new class of possible natural materials for such energy—intact plant organisms. These materials for alternative green energy do not require the extraction of minerals and the subsequent disposal of obsolete devices and equipment since plants are completely biodegradable by nature. In addition, many plants, when used in certain ways as bioenergetic devices, increase productivity and yields. As the first examples, bioelectrochemical systems based on plants are considered, with the help of which it is possible to produce electricity, and the concept of wood as a heat pump, which can become a new caloric material, is also presented.</p>