The National Renewable Energy Laboratory (NREL) team broke down all the costs that go into building solar projects of various sizes. Surprisingly, soft costs were the largest part of the costs for smaller like residential and commercial-scale projects, and the biggest reason these smaller systems cost so much more than utility-scale projects.
The next graph shows the same results broken into more detailed segments. Note that panels (modules) are very similar between local energy and larger utility projects. The biggest difference, by far, is the soft costs.
In this graph, the balance of system (BOS) includes racking and wiring. Soft costs include permitting, inspections, interconnection fees, transmission lines, sales tax, operations, and the profits of the installer.
To see the original source links and calculations, click below: