Texas has historically experienced peak demand for electricity in the summer, although Winter Storm Uri came close to equalizing summer demand in 2021. The majority (roughly 60%) of households’ heating relies on electricity. This number could increase further as the drive towards decarbonization intensifies. As additional buildings switch from natural gas to electricity for space heating, Texas could experience a significant increase in winter electricity demand. On the other hand, ambient air temperature in the winter and summer will also shift due to climate change, in particular, increasing summer temperatures and the potential for heat waves. While both heating electrification and climate change’s impacts on the grid have received attention in the past, a remaining question is how uncertainty in the timing and magnitude of these long term changes will impact seasonal electricity generation requirements and the associated relative capacity increase. In this work, we explore long term patterns in electricity demand driven by the dual effects of space heating electrification and climate change. We use an open source nodal power system model of the Electric Reliability Council of Texas (ERCOT) system to investigate a wide range of future climate and technology scenarios that evolve over time, and report results in terms of market prices, reliability and corresponding relative capacity requirements. Alongside heating electrification and the grid’s growing vulnerability to weather extremes (especially heat waves), we also account for correlated stochastic thermal unit outages/deratings, which can compound the frequency of high stress grid events. The results will allow long term system planners to better understand/project the potential future shift in grid reliability and plan for adequate supply capacity, dispatchable or otherwise, to maintain resource adequacy to mitigate any potential future shortfalls.