• foundation – is done by a specialized construction company
• foundation anchors
• Sections / parts of the tower (mostly the tower comes from another supplier/ manufacturer direct to the site)
• ground controller and switchgear
• fully assembled nacelle – it includes several components: the turbine bedplate, gearbox (unless it is a gearless turbine), mainshaft, generators converter and sometimes the transformer).
• rotor blades and hub
control and feedback control system: Data Control-, Supervisory- and communication-systems
• lightning arrester
Before the transport of components to the construction site happens, the works for civil engineering, including access roads, turbine foundations, and electrical infrastructure (eg. substation) have begun.
Suitable site access for transport is required as wind turbines are large and heavy. The site requires heavy lifting equipment. A crane is used for hoisting the tower sections, nacelle and rotor into position.
After installation of the turbines the cabling work and connection to transformers and possibly own substations and grid will be terminated. The manufacturer will test the turbine before the official tests with the owner of the turbine and the grid operator will take place.
The usual building phase of a European middle sized windfarm is 6 months.