Podcast
Questions and Answers
What is one of the main challenges associated with utilizing the best wind resources in the U.S.?
What is one of the main challenges associated with utilizing the best wind resources in the U.S.?
How is wind energy characterized with regard to its output?
How is wind energy characterized with regard to its output?
Which of the following factors contributes to less variability in wind power output offshore compared to onshore?
Which of the following factors contributes to less variability in wind power output offshore compared to onshore?
What is the primary component of wind energy production costs in the U.S.?
What is the primary component of wind energy production costs in the U.S.?
Signup and view all the answers
How has the production tax credit (PTC) affected wind energy development in the U.S.?
How has the production tax credit (PTC) affected wind energy development in the U.S.?
Signup and view all the answers
What is the function of the blades with adjustable pitch in a wind turbine?
What is the function of the blades with adjustable pitch in a wind turbine?
Signup and view all the answers
What is the cut-in speed in wind turbine operations?
What is the cut-in speed in wind turbine operations?
Signup and view all the answers
Which component of a wind turbine is responsible for measuring wind direction and speed?
Which component of a wind turbine is responsible for measuring wind direction and speed?
Signup and view all the answers
What is the general rule of thumb for spacing turbines in a wind farm?
What is the general rule of thumb for spacing turbines in a wind farm?
Signup and view all the answers
How do wind farms manage to operate with reduced personnel?
How do wind farms manage to operate with reduced personnel?
Signup and view all the answers
Why are turbine outputs variable with wind speed?
Why are turbine outputs variable with wind speed?
Signup and view all the answers
What occurs when wind speeds exceed the maximum threshold for a wind turbine?
What occurs when wind speeds exceed the maximum threshold for a wind turbine?
Signup and view all the answers
Which component converts the collected power output into a format compatible with the electrical grid?
Which component converts the collected power output into a format compatible with the electrical grid?
Signup and view all the answers
What is a major disadvantage of vertical axis turbines?
What is a major disadvantage of vertical axis turbines?
Signup and view all the answers
Which equation accurately describes the power in the wind passing through a circular area swept by a wind turbine?
Which equation accurately describes the power in the wind passing through a circular area swept by a wind turbine?
Signup and view all the answers
What limits the total power that can be extracted from wind by a turbine as stated by the Betz limit?
What limits the total power that can be extracted from wind by a turbine as stated by the Betz limit?
Signup and view all the answers
Which of the following describes a significant advantage of horizontal axis turbines?
Which of the following describes a significant advantage of horizontal axis turbines?
Signup and view all the answers
In assessing wind resources, what is an important factor to consider?
In assessing wind resources, what is an important factor to consider?
Signup and view all the answers
What is a consideration related to the economics of wind energy?
What is a consideration related to the economics of wind energy?
Signup and view all the answers
What is one of the historical uses of wind energy prior to modern electricity generation?
What is one of the historical uses of wind energy prior to modern electricity generation?
Signup and view all the answers
What is a potential impact of expanding wind energy use in the United States?
What is a potential impact of expanding wind energy use in the United States?
Signup and view all the answers
Study Notes
Wind Energy Overview
- Wind energy has been used by humans for at least 5000 B.C.
- Windmills were early precursors to modern wind turbines.
- Modern wind turbines operate on the same principle of extracting power from wind to turn a turbine.
- This process generates electricity.
Lecture Outline
1. Wind Energy Over Time
- Wind energy is one of the oldest forms of energy used by mankind.
- Sailing
- Grain milling
- Water pumping
- Milling wood
- Two basic turbine designs exist:
- Vertical axis turbines
- Advantages: Omnidirectional, can be installed in small spaces
- Disadvantages: Height limits power output
- Horizontal axis turbines
- Advantages: Omnidirectional, can be built tall with large blades, resulting in higher power output.
- Vertical axis turbines
2. Wind Power
- Power in wind passing through a circular area is calculated by a formula:
- Power = 1/2 x Air Density x Circular Area Radius x Wind velocity cubed
3. Betz Limit
- Only a fraction of wind power can be extracted to produce electricity.
- The maximum extractable power is 59% (Betz Limit).
- If all power were extracted, there would be no air movement on the other side of the turbine.
4. Blade Lift vs Drag
- Wind turbine blades have a teardrop shape for better lift.
- The angled blades cause faster wind over the top, creating a pressure differential that lifts the blades.
- Pitch controls the blade angle and thus affects power output.
- Drag counteracts lift, so a balance is needed.
5. Practical Limits on Blade Number
- One blade: 51% efficiency, higher vibration
- Three blades: 55% efficiency, less vibration, and better
- Betz Limit: 59% efficiency
- Increasing the number of blades beyond three generally does not increase efficiency significantly.
6. Wind Turbine Mechanics
- Main parts: Blades, rotor, brake, transmission, drive shaft, gears, electric generator (stator and rotor), yaw system, nacelle, wind vane, anemometer, tower.
7. Wind Capacity vs Output
- Power output varies with wind speed (power curve).
- Cut-in speed: Minimum wind speed for generating power.
- Maximum output: Wind speeds beyond a certain level may need to shut down the turbine to prevent damage.
- Efficiency varies based on speed.
8. Wind Farm Layout
- Turbine placement is optimized to minimize wind interference from other turbines.
- Spacing guidelines exist to minimize wind "wake" effect.
- Wind farms require less personnel and fuel than other power sources.
- Automated systems and remote monitoring are common.
9. Wind Resource vs Wind Farm Output
- Best locations for wind farms in the U.S.: Interior regions, mountain ridges, and offshore.
- Long transmission lines may be needed to bring power from remote locations.
10. Wind Economics
- Main costs: Capital costs (turbine, equipment, installation), O&M (maintenance, repairs).
- Variable costs are low, as fuel is free.
- Other costs: Land lease, permitting, and installation.
- Cost reductions are important as the wind industry scales.
- Government incentives, such as the Production Tax Credit (PTC), encourage wind development. This is a fluctuating incentive.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the history and technology of wind energy. This quiz covers the evolution of wind power, various turbine designs, and the principles behind generating electricity from wind. Delve into concepts like sailing, grain milling, and the Betz Limit.
