ENGINEERING PROCUREMENT CONSTRUCTION
For many utility-scale PV Projects, the project developer hires an EPC firm to perform the tasks other than those related to permits, financing, and legalities. In some case, a company may be vertically integrated between manufacturing, developing, and EPC (e.g., CER), and their exist a wide range of possible arrangements of tasks between project developers and EPCs. EPC activities (e.g., design and engineering) may occur at the same time as project developer tasks (e.g., finalization of legal agreements). The decision between in-house EPC, specially firm or generic EPC is related to the overall fiskiness of the technology.
Typical EPC's function in the process of commissioning an energy project can be broadly categorized as:engineering, procurement, construction. EPC costs for PV projects range from about $0.95/W to $1.17W depending on the size and location of the project. While PV modules and inverters account for the largest share of a PV project's cost (generally 40-50%), labor cost can be more problematic for planning purposes as they can be unpredictable adn vary strongly by locations and between unionized and non-unionized employees.
Engineering(E)
The engineering phase, which can be up to a multi-year process for very large plants, begins with a site survey and feasibility analysis and results in a full design of the PV project, including the number and arrangement of PV modules and inverters, as well as building and roads that will be used for operations and maintenance activities. This design will be used to inform procurement needs and guide construction.
Procurement(P)
Procurement entails the purchase of all physical equipment and materials and the hiring of all labor required to complete the PV project. Equipment and materials include construction vehicles and key generation infrastructure such as modules and inverters. The timing of procurement activities impacts total installed projects cost because early delivery may result in storage costs and late delivery may cause costly delays in construction.
Consturction(C)
In the construction phase, the modules and the inverters are installed and all supporting infrastructure is built. For PV projects, the term "balance of system" is used to refer to all components of a solar project apart from the modules (e.g., cables, racking syste, wiring, road gradin, inverters). Generally multiple companies will be involved in construction, with specefic tasks (e.g., electrical, roads) subcontracted from a general contractor to specialists.