Renewable hydrogen is expected to play a key role in the Iberian Peninsula, affecting power system development. While several studies have analysed the implications of the National Energy and Climate Plan (NECP) targets, the impacts of projected hydrogen demand, especially when concentrated in emerging hydrogen valleys, remain unexplored. This study introduces PyPSA-Iberia, an extension of the PyPSA-Spain model, to assess the impacts of hydrogen valleys deployment on the Iberian power system by 2030, following NECP projections and decarbonisation targets. Three scenarios are analysed to isolate the effects of hydrogen valleys and their spatial resolution. A battery deployment sensitivity analysis is also performed. Achieving 2030 targets requires substantial renewable expansion and transmission reinforcement even without hydrogen demand. Hydrogen valleys deployment further increases system requirements with additional 24-27 GW of onshore wind and 7-10 GW of solar PV. Compared with the no-hydrogen case, renewable curtailment roughly doubles, transmission reinforcement nearly quadruples, and total system costs increase by around €7 billion (16%). Higher battery capacities favour solar PV deployment, improve system performance and reduces hydrogen storage by almost 50% when battery capacity increases from 2 to 6 GW, becoming negligible at 10 GW. The analysis also demonstrates spatial resolution is essential for capturing interactions between power and hydrogen infrastructures, affecting generation and flexibility needs.