As other forms of renewable sources, the wind has the advantage of being free, inexhaustible and clean, wind have also another advantage (unlike photovoltaics) that is connected to the fact that the wind is present 24 hours a day.
A wind turbine system means a system capable of converting the mechanical energy generated by the movement of a turbine driven by the wind into electrical energy in the form of direct current.
As for hydroelectric plants it's possible to make a distinction based on the power generated, in particular we distinguish:
- Micro-Eolic: Installations with power below 3 kWp
- Mini-Eolic: Installations with power between 3 kWp and 60 kWp
- Eolic: Installations with a power capacity of more than 60 kWp
Generally the only difference between these type of systems are the size of the components, for example if the installed power increases, the dimensions of the support and the diameter of the turbine increase (for 200 kW of installed power, for example the support will be about 50 meters high)..
With a correct basic maintenance the life of these machines is around 20 years.
The most obvious advantages are related to savings on bills, reduced maintenance costs, the absence of polluting emissions, the inexhaustibility of the wind source and the possibility of realizing the installation in any place.
There are several incentives for wind power and, as for photovoltaics, there is the possibility of on-site exchange and other forms of incentives. On-site exchange means putting in the network the energy produced and not self-consumed and withdrawing it later..
There are also different types of technologies regarding the rotor:
- Horizontal axis: in this case the rotor is placed parallel to the wind direction and can be triple, double or mono with counterweight (usually the cheapest but unfortunately very noisy).
- Vertical axis: in this case the axis of the rotor is perpendicular to the wind direction, usually the turbine doesn't stop even for reduced air flow rates but it is necessary to slow down the rotation speed (to avoid breakage) for winds with a speed higher than 15/16 m/s. Typically these systems are more efficient but more expensive than horizontal axis machines.
When should a wind installation be installed?
To ensure optimal production and that the investment has a prompt economic return, the installation site must also be considered, in particular the average wind speed must be greater than 4.5 m / s and, in case of choosing the vertical axis system, we should make sure that the speed of the wind does not exceed the critical values for which the impeller would lock thanks to the protection systems and therefore the production would be zero Watts.
What size does a wind farm have?
Generally there are no particular problems of size (unlike, for example, photovoltaic systems) because the only area occupied is that needed to install the support tower and the conversion unit (charge regulator, inverter and battery pack).
How much does it cost?
A small plant costs around 3000-6000 €/kW installed and we can divide the cost in these percentages: 55% for the turbine, 10% for the charge controller, 20% for the anchorage structures, the design and assembly and 15% for the storage system.