Electic power systems are a high impact system for decarbonization; if we can significantly reduce or eliminate carbon emissions while simultaneously electrifying other sectors, the impact would be enormous. Planning investments in electric power system expansion is challenging, and planning a transition to zero-carbon systems based almost entirely on renewable and emerging technologies is both ambitious and daunting. Energy system decarbonization plans are often developed based on historical averages, spatial aggregations, and long-tertm forecasts, it is critical to consider how these proposed systems will function in an operational context. How resilient will they be to fluctuations, resource droughts, and unexpected situations? In this research, we develop practical and realistic simulation models to explore the performance of proposed strategies under a range of potential future conditions.