Bidding zones are a fundamental part of the electricity market design in Europe. Adequate attention must be paid to the development of alternative bidding zone configurations as well as their assessment. Europex therefore welcomes the opportunity to provide feedback on ACER’s high-level approach to identify alternative configurations. While we acknowledge that LMP modelling can provide useful data to support the development of potential configurations, care should be taken regarding the constraints or ‘boundary conditions’ for this exercise. In general, we believe market efficiency objectives must be considered both when developing the alternative configurations and when evaluating them.