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Wind Energy

Karl / Sanyal · 3 concepts · 5 questions

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Wind Power Formulas

Wind power: P_w = ½ · ṁ · v² = ½ · ρ · A · v³


Turbine power: P_t = c_p · P_w = c_p · ½ · ρ · (πD²/4) · v³


Betz limit: c_p,max = 16/27 ≈ 0.593

  • Theoretical maximum for ANY turbine
  • Real turbines: c_p ≈ 0.35–0.45

⚡ Power scales with v³:

  • Double wind speed → 2³ = 8× more power
  • 10% more wind speed → 1.1³ ≈ 33% more power

Air density: ρ_air ≈ 1.225 kg/m³ at sea level


Full load hours: h = W_annual [MWh] / P_rated [MW]

  • Onshore Germany: ~1,800 h/year
  • Offshore Germany: ~3,500 h/year