Wind Energy Systems

The aim of this lecture course (6 ECTS) is that students understand the physical principles of wind energy and the technology of modern wind energy systems. It consists of lectures and exercises, and is given by Prof. Dr. Moritz Diehl and Nick Harder.

Contents: 

  • global wind energy resource
  • aerodynamic principles of wind turbines
  • design of modern wind turbines
  • control of modern wind turbines
  • the electrical system of wind turbines
  • alternative concepts and airborne wind energy

When/Where

Due to Corona regulations the lectures and the exercises will take place online (at least until the mid of June) using Zoom Platform. 

The first lecture will be held on 12.05.2020 (Tuesday).

The course will be held on:

  • Tuesdays 12:30 - 14:00h
  • Wednesdays 12:15 - 14:00h

Please, use the following link to access the class for both lectures and exercise sessions. Password: 5BCxhi3Xm

The lectures will be recorded and posted on this webpage.


Course Information

The Wind Energy Systems (WES) course has two modes of instruction: lectures and  exercises. The lectures are given by Moritz Diehl. One biweekly time-slot is dedicated to an 'exercise session' that will be coordinated by Nick Harder (nick.harder@inatech.uni-freiburg.de). 

The exercise sessions are held on a biweekly basis. First exercise sheet will be provided on 20.05 after the lecture. One week after you receive the exercise sheet a video recording of the exercise solution will be posted on this webpage, and another week later an online exercise session will take place, where you can ask questions to the previous exercise sheet and a new exercise sheet will be provided. The exact schedule can be found below.

The grade for the course corresponds to the grade of the final exam. This final exam is 'closed-book,' which means that ONLY pens, a calculator, and one A4 page (that is, two sides) of notes can be used. The questions will be partially multiple-choice and partially short-answer.


Lectures

Date Title /  Slides Videos
12.05.2020

Chapter 1: Introduction

Section 1.1: Introduction (Slides)

Section 1.2: Energy content of the wind

 

Lecture_1_1_Section_1_1

Lecture_1_2_Section_1_2

13.05.2020

Section 1.3: Power density of blade area

Section 1.4: Components of modern wind turbine

Lecture_2_1_Section_1_3

Lecture_2_2_Section_1_4

Lecture_2_3_Q&A

19.05.2020

Section 1.5: Blade & Airfoil nomenclature

Chapter 2: The Wind Resourse

Section 2.1: Origins

Section 2.2: Global patterns

Section 2.3: Mechanics of wind

Lecture_3_1_Section_1_5

 

Lecture_3_2_Section_2_1&2

 

Lecture_3_3_Section_2_3

20.05.2020

Section 2.3: Mechanics of wind (continuation)

Section 2.4: Stable and unstable atmospheric stratification

Lecture_4_1_Section_2_3_continuation

Lecture_4_2_Section_2_4

 

26.05.2020

Section 2.5: Statistics of wind

Section 2.6: Spectral properties of wind

 

Lecture_5_1_Section_2_5

Lecture_5_2_Section_2_6

Lecture_5_3_Weather_data

27.05.2020

Section 2.6: Spectral properties of wind (continuation)

Chapter 3: Aerodynamics of Wind Turbines

Section 3.1: Wakes (Wind_wakes_image)

Section 3.2: Actuator disc model and the Betz' limit

Lecture_6_1_Section_2_6_continuation

 

Lecture_6_2_Section_3_1

Lecture_6_3_Section_3_2

02.06.2020

Section 3.2: Actuator disc model and the Betz' limit (continuation)

Section 3.3: Wake rotation & rotor disc theory

Lecture_7_1_Section_3_2_continuation

Lecture_7_2_Section_3_3

09.06.2020

Section 3.3: Wake rotation & rotor disc theory (continuation)

Section 3.4: Blade element momentum (BEM) theory

Lecture_8_1_Section_3_3_continuation

Lecture_8_2_Section_3_4_part1

10.06.2020 Section 3.4: Blade element momentum (BEM) theory (continuation) (screenshot at end of lecture)

Lecture_9_1_Section_3_4_part2

Lecture_9_2_Section_3_4_part3

16.06.2020 Section 3.4: Blade element momentum (BEM) theory (continuation)

Lecture_10_1_Section_3_4_part4

Lecture_10_2_Section_3_4_part5

Lecture_10_3_Section_3_4_part6

23.06.2020 Invited Talk on Industrial Practice of Wind Energy Converter Control. Additional info

Slides

Lecture_11_Invited_talk_Part1

24.06.2020 Invited Talk on Industrial Practice of Wind Energy Converter Control. Additional info Lecture_12_Invited_talk_Part2
30.06.2020

Chapter 4: Mechanics & Dynamics of Wind Turbines

Section 4.1: Steady loads in normal operation

Section 4.2: Stress and strain

Lecture_13_1

Lecture_13_2_Section_4_1

Lecture_13_3_Section_4_2

01.07.2020

Section 4.3: Static beam bending

Section 4.4.1: Intro: spring-mass-damper system

Section 4.4.2: Eigenmodes

Section 4.4.3: Rayleighs method

Lecture_14_1_Section_4_3

Lecture_14_2_Section_4_4_part1

Lecture_14_3_Section_4_4_part2

Lecture_14_4_Section_4_4_part3

08.07.2020

Section 4.4.4: Dynamic beam equation

Section 4.4.5: Tower eigenmodes

Section 4.4.5: Stiff & soft towers

Lecture_15_1

Lecture_15_2

Lecture_15_3_Section_4_4_part_4_5

Lecture_15_3_Section_4_4_part_6

10.07.2020

Hike to Rosskopf Wind Turbines at 2 PM.  Additional info is in the Special Events section below

(participation is optional)
14.07.2020

Section 4.5: Blade oscillation & centrifugal stiffening

Chapter 5: Control of Wind Turbines

Section 5.1: Sensors and Actuators in wind turbines

Lecture_16_1_Section_4_5_part1

Lecture_16_2_Section_4_5_part2

 

Lecture 16_3_Section_5_1

15.07.2020

Section 5.2: Control system architecture

 

Section 5.3: Control of variable speed turbines

Lecture_17_1_Section_5_2

Lecture_17_2_Section_5_3_part1

Lecture_17_3_Section_5_3_part2

21.07.2020 Section 5.4: Torque control at subrated power

Lecture_18_1_Section_5_4_part1

Lecture_18_2_Section_5_4_part2

28.07.2020

Section 5.5: Thrust jump at nominal wind speed

Chapter 6: Alternative Concepts

Section 6.1: Vertical axes wind turbines

Lecture_19_1_Section_5_5

 

Lecture_19_2_Section_6_1

29.07.2020

Section 6.1: Vertical axes wind turbines

Section 6.2: Airborn Wind Turbines

Lecture_20_1_Section_6_1

Lecture_20_2_Section_6_2_part1

Lecture_20_3_Section_6_2_part2

 


Exercises

Date Title Link
20.05.2020 Exercise Sheet 1 Exercise_Sheet_1
27.05.2020 Solution to Exercise Sheet 1

Exercise_Sheet_1_Solution

Exercise_1_Python_script

03.06.2020 Q&A session + Exercise Sheet 2

Exercise_Sheet_2

10.06.2020 Solution to Exercise Sheet 2 Exercise_Sheet_2_Solution
17.06.2020 Q&A session + Exercise Sheet 3 Execise_3
24.06.2020 Solution to Exercise Sheet 3 Exercise_3_Solution
08.07.2020 Q&A session + Exercise Sheet 4

Exercise_Sheet_4

15.07.2020 Solution to Exercise Sheet 4 Exercise_4_Solution
22.07.2020 Q&A session + Exercise 5 online classroom

 


Special Events

  • Invited Talk on Industrial Practice of Wind Energy Converter Control. Tuesday, June 23, 2020, 12:30. For more information, follow this link.

  • The tour to the wind turbines on Rosskopf will take place on July 10 afternoon. All information can be found on https://www.syscop.de/event/walk-rosskopf-wind-turbine

 


Resources

Wind Energy Handbook is available here

Wind Energy Explained: Theory, Design and Application is available here

 

!!! The updated lectures script can be found here !!!

!!! The mock exam can be found here !!!

 

This course was also held in SS2018, all the materials from that course are available here.

 

Links of interest

2020-05-12 Report on renewable power generation costs in 2018 (by IRENA(PDF)

2020-05-19 Which way a wind turbine turns might not seem to matter (by the Economist(screenshot)

2020-05-19 Atmospheric circulation patterns (from wikipedia)

2020-05-26 Article on the Global Energy Transition (by the Economist)

2020-06-02 Albert Betz: Wind-Energie. Cover, Turbine Illustrations, Concluding Sentence