Hydrogen production through the electrolytic splitting of water using photoelectrochemical cells (PEC cells) has shown promising efficiency, with the best devices achieving up to 19% energy conversion. However, bubble formation during the process leads to energy losses, affecting performance. Researchers at HZB explored the impact of operating PEC cells at elevated pressures between 1 and 10 bar. By pressurizing the PEC flow cells, they observed a significant reduction in energy loss and an increase in efficiency. The study revealed that operating at 8 bar pressure could halve energy losses and potentially boost overall efficiency by 5-10%. The team's multiphysics model enabled the identification of key parameters, such as bubble behavior at electrodes, aiding in optimizing performance. Prof. Dr. Roel van de Krol highlighted the potential for these findings to enhance efficiencies of various electrochemical and photocatalytic devices, marking a significant step towards improving sustainable hydrogen production technologies.