A Wind Turbine farm, is a Group of Wind turbines in the same location, used to produce electricity. Wind farms vary in size from a small number of turbines to several hundred wind turbines covering an extensive area. Wind farms can be either onshore or offshore.
Because they require no fuel, wind farms have less impact on the environment than many other forms of power generation and are often referred to as a good source of green energy.
Design & Location of Wind Farms
Typically they need to be spread over more land than other power stations and need to be built in wild and rural areas. Location is critical to the overall success of a wind farm. Additional conditions contributing to a successful wind farm location include: wind conditions, access to electric transmission, physical access, and local electricity prices.
The faster the average wind speed, the more electricity the wind turbine will generate, so faster winds are generally economically better for wind farm developments.The balancing factor is that strong gusts and high turbulence require stronger more expensive turbines, otherwise there is a risk of damage.
The average power in the wind is not proportional to the average wind speed. For this reason, the ideal wind conditions would be strong but consistent winds with low turbulence coming from a single direction.
Learn About Wind Turbine Farm Installation from Scratch – A Step-by-Step Guide on how exactly these gigantic mysterious structures are Transported, Assembled, and Installed.
Ideal locations & Site Screening for Wind Farms
- Mountain passes are ideal locations for wind farms under these conditions. Mountain passes channel wind, blocked by mountains, through a tunnel like pass towards areas of lower pressure and flatter land.
- Usually sites are screened on the basis of a wind atlas, and validated with on-site wind measurements via long term or permanent meteorological-tower data using anemometers and wind vanes.
- Meteorological wind data alone is usually not sufficient for accurate siting of a large wind power project. Collection of site specific data for wind speed and direction is crucial to determining site potential in order to finance the project.
- Local winds are often monitored for a year or more, detailed wind maps are constructed, along with rigorous grid capability studies conducted, before any wind generators are installed.
- The wind blows faster at higher altitudes because of the reduced influence of drag. The increase in velocity with altitude is most dramatic near the surface and is affected by topography, surface roughness, and upwind obstacles such as trees or buildings. At altitudes of thousands of feet/hundreds of metres above sea level, the power in the wind decreases proportional to the decrease in air density.
- Often in heavily saturated energy markets, the first step in site selection for large-scale wind projects, before wind resource data collection, is finding areas with adequate available transfer capability (ATC).
- ATC is the measure of the remaining capacity in a transmission system available for further integration of two interconnected areas without significant upgrades to existing transmission lines and substations.
- Significant equipment upgrades have substantial costs, potentially undermining the viability of a project within a location, regardless of wind resource availability. Once a list of capable areas is constructed, the list is refined based on long term wind measurements, among other environmental or technical limiting factors such as proximity to load and land procurement.
Major factor in wind-farm design
- A major factor in the Wind Farm Design is the spacing between the turbines, both laterally and axially (with respect to the prevailing winds). The closer the turbines are together, the more the upwind turbines block wind from their Rear Neighbours (wake effect).
- However, spacing turbines far apart increases the costs of roads and cables, and raises the amount of land needed to install a specific capacity of turbines. As a result of these factors, turbine spacing varies by site.
- Generally speaking, manufacturers require a minimum of 3.5 times the turbine’s rotor diameter of clear space between each adjacent turbine’s respective spatial envelope. Closer spacing is possible depending on the turbine model, the conditions at the site, and how the site will be operated.
- Airflows slow down as they approach an obstacle, known as the ‘blockage effect’, reducing available wind power by 2% for the turbines in front of other turbines