The thesis presented deals with decentralised energy generation and storage systems, focusing on their economic potential and their practical implementation. It introduces the E+grid concept through three projects that have already been implemented or are in the process of being implemented. It presents the working principal and the detaieled structure of the E+grid system. This is followed by a review of an actual business assignment building on the experience gained from the E+grid projects. The assignment is to investigate whether it is possible to implement a system that has a less than four years return on investment. This project takes place in Great Britain, so it is necessary to examine the properties of the local electricity market. Many unique economic opportunities present themselves (such as the Frequency Response service) through entering into a contract with the Transmission System Operator (National Grid) for a unit capable of demand response. The thesis presents all these opportunities and the conditions for entering such a contract. After evaluating the opportunities and choosing the ones suitable for the assingment and also examining the components of the electricity charges, the thesis recommends the addition of energy storage systems to the costumer’s sites. The thesis presents a control strategy that fully capitalizes on the opportunities. Finally the results of economic return calculations are presented.