Vernier Software and Technology
Vernier Software & Technology

Power Curves

Figure from experiment 13 from Renewable Energy with Vernier

Introduction

Wind turbine power curves describe how much power a wind turbine can extract from the wind at a variety of different wind speeds. Most power curves have a fairly similar shape, but each model of wind turbine has a unique power curve based on its design characteristics. By examining the power curve, you can tell the wind speed at which a wind turbine will start generating power, the wind speed at which it produces its maximum power output, and in what range of wind speeds it can safely operate.

The following concepts are important to understand when discussing power curves for wind turbines:

Cut-in Speed: The cut-in speed is the wind speed at which the turbine blades begin to rotate the generator shaft. This value is dependent on the number of blades, blade design, turbine inertia, and how smoothly the generator operates (gears or other friction elements in the drive train can affect this).

Maximum Power Output: This value is the maximum amount of power the turbine can produce. In Figure 1, the maximum amount of power the turbine can produce is approximately 105 kW at a wind speed of about 15 m/s.

Overspeed Protection: A wind turbine must be able to protect itself by slowing down in extreme wind speeds (in the example, above 15 m/s). At these speeds, the rotor or generator may spin too fast and cause electrical or mechanical problems. To mitigate the potential for damage, engineers have developed several different strategies: 1) feathering or adjusting blade pitch to make the blades less aerodynamic 2) applying a mechanical brake to slow the rotor 3) furling or turning the rotor so the plane of the rotor is parallel to the wind direction rather than perpendicular.

Power curves help us understand certain characteristics of a wind turbine, such as how much instantaneous power a turbine may generate at a specific wind speed. However, power curves do not necessarily give us a good idea of how much energy a wind turbine will produce at a given location because average wind speeds are generally well below the wind speed required for maximum power output.

Objectives

  • Describe a power curve and its importance in understanding blade efficiency.
  • Generate a power curve for a classroom wind turbine.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Renewable Energy with Vernier

See other experiments from the lab book.

1Renewable Energy: Why is it So Important?
2What is Energy?
3Project: Energy Audit
4Voltage and Circuits
5Current and Resistors
6Mechanical Power
7Generators
8Exploring Wind Turbines
9Effect of Load on Wind Turbine Output
10Blade Variables and Power Output
11Solidity
12Turbine Efficiency
13Power Curves
14Power and Energy
15Project: Maximum Energy Output
16Project: Build a Wind Farm
17Exploring Solar Panels
18AEffect of Load on Solar Panel Output
18BFill Factor and IV Curve of a Solar Panel
19Variables Affecting Solar Panel Output
20Effect of Temperature on Solar Panel Output
21Project: Build a Solar Charger
22Exploring Passive Solar Heating
23Variables Affecting Passive Solar Heating
24Exploring Solar Collectors
25Variables Affecting Solar Collectors
26Project: Solar Cooker

Experiment 13 from Renewable Energy with Vernier Lab Book

<i>Renewable Energy with Vernier</i> book cover

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