The electrification of the transport sector, combined with the growing produc- tion of renewable energy, will place significant demands on the electrical grid. This project has developed a simulation tool, Powerflow that allows for the simulation of the voltage variablity in the electrical grid. This tool can give insight into how the grid is effected by these changing demands. During de- velopement of Powerflow the project group has focused on value creation for the client, documentation of experience from working with the agile process Scrumban and investigated the value of creating and following a system ana- tomy. The project group has drawn the conclusion that continous contact and focus on the needs of the client is of paramount importance in order to crea- te value for the client. In addition, the group’s experience during the project has led to the conclusion that clearly defined roles, thorough planning, and continuous evaluation of the work process are highly valuable in this type of project. Moreover the group has created and followed a system anatomy. The anatomy has given the group insight that a model of a system both can acce- lerate the rate of developement as well as give increased understaning of the system to all developers. The group has also concluded that the implemen- tation of several solution algorithms, each tailored to different electrical grid structures, is essential for an effective voltage fluctuation calculation tool.