In 2018 the Dutch government, businesses and other stakeholders started negotiating an agreement to combat climate change (het Klimaatakkoord). Energy consumption is changing and more Renewable Energy Sources (RES) are implemented. While these changes are ongoing, the Distribution System Operators (DSOs) must ensure no congestion occurs in the grid. However, it seems congestion problems are already arising. As a lot of research has been done on Energy Storage Systems (ESSs) and Electric Vehicles (EVs) for congestion prevention, research on movable ESSs is missing. This thesis proposes a method for congestion prevention by Relocatable Energy Storage Systems (RESS). A Mixed Integer Linear Program (MILP) is proposed to minimise the amount of RESS used and penalise displacement. An algorithm which includes a Minimum Cost Maximum Matching is used to determine the planning of each individual RESS. The results show that, for the test grid designed, it is beneficial to use RESS instead of statically placed ESS in the grid.