A system, method, and apparatus for generating hydroelectric power from subsurface wells penetrating or terminating in fluid-bearing, subterranean zones or intervals containing gas, oil, water, or any combination of these fluids. The system involves methods and apparatus summarized in a five-step process that includes: Phase 1—Fluid Production, Phase 2—Fluid Gathering and Combination, Phase 3—Hydropower Electricity Generation, Phase 4—Fluid Processing, and Phase 5—Fluid Pumping, Distribution, and Injection.