# Wind power calculation

With nPro power generation profiles for wind turbines in hourly resolution can be generated. On this page it is documented how these are calculated.

## How are wind power profiles calculated?

In nPro, the wind speed at hub height of the wind turbine is calculated in a first step. For this purpose, the power law according to Hellmann is used: $$w_\mathrm{hub} = w_\mathrm{ref} \left(\frac{h_\mathrm{hub}}{h_\mathrm{ref}}\right)^a$$ Here, \(w_\mathrm{hub}\) is the wind speed at hub height, \(w_\mathrm{ref}\) the measured wind speed, \(h_\mathrm{hub}\) the hub height, \(h_\mathrm{ref}\) the reference height at which the wind speed measurement took place, and \(a\) the Hellmann coefficient. In a second step, the generation power of the turbine is calculated with power curves from manufacturer data. In Table 1 the power curve of the wind turbine Enercon E141 is illustrated.

Wind speed at hub height | Power generation |
---|---|

0 m/s | 0 kW |

1 m/s | 0 kW |

2 m/s | 22 kW |

3 m/s | 104 kW |

4 m/s | 260 kW |

5 m/s | 523 kW |

6 m/s | 920 kW |

7 m/s | 1471 kW |

8 m/s | 2151 kW |

9 m/s | 2867 kW |

10 m/s | 3481 kW |

11 m/s | 3903 kW |

12 m/s | 4119 kW |

13 m/s | 4196 kW |

14 m/s | 4200 kW |

... | 4200 kW |

25 m/s | 4200 kW |

25.1 m/s | 0 kW |