The society is utilising more and more information and communication technologies and it is becoming more dependent on reliable energy resources. There will also be more distributed energy resources that are connected to the electrical network. The coordinated management and automation of such resources becomes more important and includes new challenges and possibilities. Distribution requires new ways of working and management of processes producing integrated added value. In the area of distributed energy there can be seen three commercial levels: services supporting the business and business networks, management and utilisation of local energy resources and control of individual production and consumption units. Information and communication technologies and automation are essential in gaining the aims and in developing the means and tools for controlling this kind of systems (production, transfer, distribution, storage, use). The aim of the report is to describe the area of distributed energy systems and identify the most important systems and implementation concepts related to them. The focus of the research was on systems less than 500 kW. New and emerging business models and implementation methods were utilised and taken as a starting point. Descriptions of cases of distributed energy systems were used to concretise the areas of the research. The results can be used as a review on the subject and as a basis for further research.