The security of electricity supply is on a high level and an important location-specific advantage of Germany. Due to the rising number of facilities based on renewable energy sources, keeping up the high security level in the medium- and long-term becomes a challenge. The rising share of volatile, not definitely predictable feed-in and the anticipated decommissioning of thermal power plants lead to a reduction in reliable generation capacities. In this context and considering the widespread use of innovative equipment and concepts – such as flexible high-voltage direct current transmission systems, variable distribution transformers, reserve supply by plenty of small power plants and various smart grid technologies – system security is to be assessed continuously using adapted methods taking into account new circumstances. Methods and procedures developed by IAEW help detecting interdependencies at an early stage and thus ensure future system security.