1. An overview of wind energy 3/5/2018

2. World-wide electricity production
79%
Dominant source after hydro
Source: obser’ER

3. Global installed capacity of wind power
Source: GWEC
Capacity in 2017
Cumulative : 539 GW
Can cover more than 5% electricity demand
Newly added
More than half from outside EU and US
From China, India, Brazil, …

4. Wind energy by country Cumulative wind capacity in 2017
World’s top : 35% from China
Share in whole EU : 33%
188 GW
89 GW
178096/539581
China overtook US in 2010
penetration = the percentage of demand covered by wind energy in a certain region
Total amount of wind energy produced (annually) / Gross annual electricity demand
Source: GWEC
Domestic electricity generated by wind
Percentage of power produced to total in a country
World’s top : 42% in Denmark (2015)

5. Growth of power and size
Cited from Blaabjerg, F., & Ma, K. “Future on power electronics for wind turbine systems” (2013)
Future on Power Electronics for Wind Turbine Systems
Average : 2-3 MW (2016)
Products developed now : MW
Largest capacity : 8 MW with 164 m diameter
1 × 1 GW nuclear reactor = 500 × 2 MW wind turbines

6. Structure
Source: US Department of Energy

7. Offshore wind High wind speed Large energy production
Stable conditions of wind Reliable source
Expensive and difficult to build and maintain
Damage from wave and heavy storms
Onshore
Shallow
~30 m
Deep
50 m ~
Offshore
Source : SIEMENS
Source : NREL
First wind turbine : 220 kW, in Sweden (1991)
Largest offshore wind farm : London Array
630 MW, 175 turbines

8. Vertical axis wind turbine
Omni-directional (no need of yaw mechanisms)
Less complexity of structure
Generator positioned close to ground
Darrieus type
Savonius type
Source : Creative Commons (left), renugen (right)

9. Energy conversion 𝝆×𝑨×𝑽 Rotation Wind (mechanical energy)
(kinetic energy)
Rotation
(mechanical energy)
Electricity
Power
of wind
= 𝟏 𝟐 × 𝒎 × 𝑽 𝟐
𝟏 𝟐 ×𝝆𝑨× 𝑽 𝟑
Density of air
𝝆×𝑨×𝑽
Proportional to
Swept area
Cube of wind speed
Wind speed 𝑽
Double wind speed
Power increased by 8 times
Area 𝑨

10. Efficiency Power coefficient Ratio of extracted power to wind energy
Determined by design of wind turbine
Theory : 59% (maximum)
Actual : 45 to 50% for modern large wind turbines
Electric energy
Energy from wind
Conversion of energy
100 %
30-40 %
Aerodynamic loss
50-60 %
(at blade and rotor)
p660
Mechanical loss
4 %
(at gear)
Electrical loss
6 %
(at generator)

11. Capacity factor Ratio of actual output to rated power
Affected by weather variations, downtime, etc…
Source: Swedish Energy Agency, Vindkraftsstatistik 2013
Power production during a week in Feb.
20-40 % for most wind turbines
45-60% on very good wind sites

12. Research at Division Focus on vertical axis wind turbine
Company Vertical Wind AB
Developed by Univeristy
H-rotor type
Located in Falkenberg and Marsta
Research interest in
Generator design
Power modeling
Aerodynamics
… so on
Falkenberg Three 24m-long blades, 40m height
Marsta 6m height
Vertical axis wind turbine in Falkenberg

13. Thank you for your attention!