The growing share of electricity generated from intermittent renewable energy sources as well as increasing market-based cross-border flows and related physical flows are leading to rising uncertainties in transmission network operation. This paper presents the current and possible future operational challenges from TSOs’ experiences, and provides a comprehensive overview of expected features that a toolbox
should contain for the stable operation of the transmission network. In addition, it outlines the research vision of the UMBRELLA project, namely better use of renewable energy forecasts, optimization of transmission system operation, and risk-based security assessment, as the possible solution to tackle the aforementioned challenges. In the end, a brief introduction to the UMBRELLA project has been incorporated.