An important process for navigating the uncertainties associated with the energy transition is power system planning. Energy system models are considered to be useful tools for supporting the power system planning process but are limited in several ways. Firstly, energy system models often have a high computational burden, limiting the possibility of conducting a large range of experiments. Secondly, to reduce their computational burden some energy system models have limited temporal detail, resulting in overestimation of VRE capacity in the system, underestimation of VRE curtailment, and undervaluation of flexible resources. Thirdly, many energy system models are considered to be ‘black boxes’ due to their high complexity and limited transparency. To address these problems related to models for power system planning, the Operation and Planning Model (OPM) has been developed in this study. The OPM is a myopic electricity system cost-optimisation model with a high level of temporal detail and a relatively low computational burden to allow for exploring the development of a national energy system, focussing on the interplay between demand, supply, and storage of electricity.
The OPM has been applied to a reference case and two targeted experiments on the development of the Dutch electricity system from 2030 to 2050. The reference case showed that in case natural gas-fired power plants with carbon capture and storage are included in the OPM, the electricity system becomes highly dependent on this technology for the provision of electricity and flexibility. If this technology is not included in the OPM, the maximum number of additional generation and storage units per year is shown to have a major impact on system development. In case this factor is sufficiently high to not limit investments, the system becomes mainly dependent on onshore wind for the provision of electricity and energy storage in underground hydrogen storage facilities for flexibility. In case this factor is limited to a lower level, the system develops a more balanced technology mix. Multiple recommendations are made for future research continuing on the work presented in this report.

1. Applying the OPM to more experiments can result in more in-depth insights into factors influencing the development path of the Dutch electricity system. This could entail analysing scenarios with variations of the costs for the different technologies to assess under which cost levels the system develops a favourable or unfavourable technology mix.
2. The spatial scope of the OPM can be expanded to assess the importance of cross-border trade for ensuring system reliability and gaining insights into the co-evolution of interconnected electricity systems.
3. The demand side is assumed to be inflexible in the OPM. Including demand side flexibility can result in a more accurate view of the electricity system's development between 2030 and 2050.
4. The used time series data is based on a single year. An alternative approach is suggested in which time series data from multiple years is used which would better represent that perfect forecasting of capacity factors and electricity demand for a future year is not possible.