Alongside the determination of the energy yield, it is vital to establish the total project costs so that the financial viability of the project can be estimated.
Some of these costs are incurred during the planning stages, but the bulk of the costs are accounted for in the purchase of the wind turbines and their installation costs. These typically break down as: turbine purchase at 76%; electrical elements, including grid connection 11%; foundations 6%; land rent 4%; and 3% for the rest.
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An essential feature of the development process is early discussions with the planning authority.
Developers first need to acquire planning permission to install the meteorological mast that will measure site wind speeds.
Early cost outlays will be required for the purchase and installation of the meteorological mast and then, in the longer term, the purchase of metrological data from a suitable source in order to compare wind measurements and establish the wind potential on the site.
Another consideration for early on in the process is the environmental statement which will likely need to be commissioned.
That will include a number of specialist studies of: fauna and flora; birds; protected archaeological sites; noise; visual aspects, including computerised photomontages of how the site will look; possible TV and radio interference; disturbance from traffic movements during construction; and arrangements for disposal of soil that may be displaced from foundations.
The completed environmental statement is then submitted to the planning authority for approval. Informal negotiations often precede a formal submission.
In parallel with negotiations with the planning authority, the electricity utility will seek information on the electrical characteristics of the wind turbines and assurances that the requirements for connecting to the grid code will be met. Once all the permissions are in place, construction can begin.
The financial elements involved in construction are numerous, but the main cost considerations include: arranging access to the site and laying temporary roads if necessary; erecting temporary site construction facilities including on-site pathways; excavating and installing wind turbine foundations; tendering for, purchasing and installing wind turbines; excavating and installing underground cables ; building a substation; and connecting to the electricity grid
Once construction is complete, the wind farm can be commissioned, at which point the owner can begin to earn some revenue from energy production. Once in operation, the planning authority may require noise measurements to prove that any imposed limits have not been exceeded.