Abstract: This invention is embodied in a cost-optimization device for the layout and construction of a utility-scale photovoltaic (“PV”) power plant. The optimization device employs a set of algorithms designed to find the most cost-effective solution under given conditions. The algorithms are written in computer machine readable code and are highly customizable for the specific tracker equipment requirements and owner/builder/maintainer specifications or preferences. The preferred optimization device comprises three principal stages (or “units”) of computing: (1) an objective-state unit, (2) an optimum-feasible unit, and (3) a grading unit. In the first stage, the objective-state unit cost-optimizes site grading by orienting a ruling line between a maximum and a minimum pile reveal length for each tracker in the project (the objective-state solution”). When compared to the existing site topography, the ruling line indicates cost-optimized cut and fill locations.