Access to reliable and sustainable electricity is fundamental for economic and social development. Zambia, like many Sub-Saharan African countries, faces significant challenges in achieving universal electricity access due to its heavy reliance on hydropower, which accounts for approximately 84% of total power generation. This dependence on hydroelectricity makes the power system highly vulnerable to climatic variability, particularly droughts, leading to severe power shortages and economic disruptions. This study develops a power system generation and transmission capacity expansion model using PyPSA-Earth to assess cost-effective, reliable, and climate-resilient energy transition pathways under universal electricity access.