The development and progress of mankind leads to an increased emission of harmful gases in the entire world industry, which is one of the leading factors of climate change. In order to reduce CO2 emissions, the use of fossil fuels and other conventional energy sources, according to numerous international regulations, is being replaced by renewable energy sources, among which is the use of geothermal energy. Geothermal energy is "clean" energy that has no negative impact on the environment, and the main advantage compared to other renewable sources is its availability regardless of weather conditions. The use of geothermal energy is important for obtaining electricity, for cooling and heating buildings. The use of geothermal energy is achieved by performing various systems based on geotechnical experience and knowledge, and among others, they include earthworks and drilling works based on the geological and geomechanical characteristics of the soil. With regard to encouragment of geothermal energy utilization and application for the sake of economy, the implementation of its utilization has been attempted for the last 30 years or so in underground structural and foundation systems, which are collectively called energy structures. Energy structures work on the principle of heat transfer using a heat pump system, the primary task of which is to utilize the uniform temperature of the soil at a certain depth during different periods of time for the purpose of heating and cooling the building. Energy piles are underground buildings that fall into the category of energy structures, and in addition to their basic role as deep foundation of various buildings, they participate in the exploitation of geothermal energy. The change in temperature depending on the heating and cooling of the building can affect the mechanical behavior of the piles and the contact surface of the soil and piles, and although the application of energy pile systems is becoming more widespread, data on the long-term behavior of the soil and piles is limited. In this paper, the characteristics and functioning of energy pile, their divisions, applications, advantages and disadvantages and the solutions to these problems, are explained, with an emphasis on the challenges and problems during their implementation and the mentioned problems.