In utility-scale solar, the installed price generally spans $0. 50 per watt, with total project costs rising from a few million dollars for small projects to several hundred million for large, grid-connected facilities. Assumptions: region, specs, labor hours. Per-unit costs commonly fall in the 0. Assumptions:. Cost ranges for solar power plants vary with capacity, technology, and location. 40 per watt range, translating to roughly $1. A 1-MW solar farm costs $900,000 to $1,300,000 to build and powers 100 to 250 homes. A typical 50 MW project may cost. The total cost of a solar project depends on a variety of factors including, the size of the system, the types of solar panels being used, the complexity of the engineering design, and finally, the cost of land needed to construct a large-scale project.