The topic of this paper is the application of blockchain technologies in the modern power system. Blockchain technology is based on the principle of peer to peer. Each node in the system receives its own copy of the "chain" that it stores. To add a new part to the chain participants must work together. One node issues a transaction that is confirmed by other users. There are many types of consensus, and the most commonly used are Proof of Work and Proof of Stake. So called miners solve a complex algorithm to confirm the transaction. It is an extremely complex process but it ensures the constant function of the network. Blockchain throws out the third party in the exchange of information that is replaced by transparent and secure network. This way each of the parties profit and they have a reliable system to use. The first unit that is discussed in this paper is solar power plant. The technology and its application are explained in more detail. The necessary parts for the construction of solar rooftops are listed and each part of the system is explained in more detail. It explains the main work of the whole system, which is based on three basic systems: a network-connected system, a stand-alone system and a hybrid system. Each of these three systems is explained in more detail. The second unit that is discussed are battery tanks. Throughout the whole chapter, the basic concepts and characteristic quantities related to battery tanks are explained. Three types of battery tanks are listed: lead, l-ion, and salt water batteries. Each of these containers is described in more detail to better understand the system. Battery containers from today's market are listed. It is easy to see the trend of large company entering the area. At the end of the chapter, a review of the costeffectiveness of battery packs in households is given. The third unit that is discussed are microgrids. In this chapter, the reader can learn more about microgrids. The basic concept of microgrids are explained. There are 3 basic types of micronetworks: urban, remote and agile. Each of these species is explained in more detail. After that the chapter explains microgrid architecture in more detail and then the management possibilities of the grid. Grid managment is separated in three groups: primary, secondary and tertiary. This management is used according to hierarchy. At the end of the chapter, some advantages and disadvantages of the microgrids concept are listed. The fourth unit is description of Blockchain technology. This chapter explains the working principle of the technology. Several types of consensus are mentioned and they are explained in more detail. Bitcoin and Ethereum are briefly explained as the most famous cryptocurrencies. The chapter explains technology in great detail and shows its architecture and states the criteria for technological suitability. The fifth unit is focused exclusively on the application of blockchain technology in the power system. The enormous potential of technology to improve the business of energy companies is explained. It goes through the wholesale of electricity and gives a possible improvement in the structure of the market. The end of the chapter talk about digitalization and IoT platforms. Digitization will capture every sector in the future. The text expresses an essential explanation of how this will be implemented in the power system. The sixth unit talks about Blockchain applications in micronets. The general idea of it all is to create a functional platform through which users can trade their energy surplus. Users can buy energy from neighbors or any other user of the platform. Some of the projects that stand out are Brooklyn MicroGrid from LO3 Energy, Power Ledger and SunContract. These three platforms are explained in more detail and Key2Energery is cited as an early project with great potential. The seventh and final unit introduces readers to some of the problems of blockchain technology. Although the technology has many positive aspects, there are also negative ones in terms of energy consumption and CO2 emissions. This chapter provides estimates of energy consumption and CO2 emissions. At the same time, the impact of technology on society and the overall global economy is stated, and figures are attached.