Harnessing the Wind: Design,
Operation, and Efficiency of
Wind Turbines
Introduction
• Wind energy is a clean, renewable energy
source.
• Growing importance due to climate change
and energy demand.
• Wind turbines convert wind's kinetic energy
into electrical energy.
• Fun fact: A 1 MW wind turbine can power
around 300 homes.
Classification of Wind Turbines
• Horizontal Axis Wind Turbines (HAWTs):
Common, blades rotate perpendicular to
wind.
• Vertical Axis Wind Turbines (VAWTs): Blades
rotate parallel to wind direction.
• Diagram comparing HAWT vs VAWT.
Working Principle
• Wind turns the blades due to lift forces.
• Rotor connected to shaft spins generator.
• Mechanical to electrical energy conversion.
• Diagram showing energy conversion process.
Aerodynamics of the Blade
• Blades shaped like airfoils.
• Wind causes lift > drag => rotation.
• Equation: L = 1/2 * ρ * V^2 * A * C_L
Power Extracted from the Wind
• Equation: P_wind = 1/2 * ρ * A * V^3
• Power increases with cube of wind speed.
• A = Swept area (πr^2)
Betz Limit
• Max power coefficient C_p = 0.593
• Equation: P_max = (16/27) * 1/2 * ρ * A * V^3
• No turbine can extract more than 59.3% of
wind power.
Actual Power Output
• Equation: P = C_p * 1/2 * ρ * A * V^3
• C_p: power coefficient (real-world max ~0.45)
• Example calculation (insert numbers for
illustration).
Components of a Wind Turbine
• Rotor Blades
• Hub
• Nacelle (gearbox, generator)
• Tower
• Yaw system
• Brake system
• Diagram of turbine with labeled parts
Generator Types
• Squirrel Cage Induction Generator (SCIG)
• Doubly-Fed Induction Generator (DFIG)
• Permanent Magnet Synchronous Generator
(PMSG)
Control Systems
• Pitch control: Changes blade angle.
• Yaw control: Aligns turbine with wind.
• Braking system: Prevents overspeed.
Wind Speed Characteristics
• Cut-in speed: ~3 m/s
• Rated speed: ~12–14 m/s
• Cut-out speed: ~25 m/s
• Power vs Wind Speed Curve
Site Selection
• Wind speed & consistency (anemometry)
• Land use, grid access
• Environmental and visual impact
Capacity Factor
• Equation: Capacity Factor = Energy Output /
(Rated Power * Time)
• Real-world values: ~30–45%
Environmental & Economic
Benefits
• No emissions during operation
• Low operating cost
• EPBT < 1 year in good locations
Challenges
• Intermittency
• Wildlife impact (birds, bats)
• Noise and aesthetic concerns
• Grid integration
Technological Innovations
• Offshore floating turbines
• Smart blade materials
• Predictive maintenance using AI
Case Study / Real Example
• Ghana wind potential: Ada, Anloga, coastal
regions
• Global leader: Denmark (50%+ energy from
wind)
Summary
• Wind turbines are key to sustainable energy
• Efficiency governed by physics (Betz Limit)
• Technology continues to improve
Q&A
• Thank the audience
• Invite questions
