Mathematica is conducting evaluations of the Millennium Challenge Corporation-funded energy sector project in Tanzania. The evaluation covers four major components of the project: (1) the transmission and distribution systems rehabilitation and extension (T&D) activity, (2) a customer-connection financing scheme initiative to facilitate lower-cost electricity connections in selected areas, (3) the Kigoma solar power activity, and (4) the Zanzibar interconnector activity, or “cable” activity. Our interventions include an impact evaluation of the T&D activity using a quasi-experimental design, an impact evaluation of the FS initiative using a group random assignment design, and performance evaluations of the Kigoma solar activity and the Zanzibar cable activity using pre-post comparison designs. In this report, we describe our evaluation designs for all four components of the energy sector project.