1. The Coming Power of Wind: Perspectives and Prospects
Soirée Technique, Dec 8th
Session 4: Renewable Energy Sources
Presented by Dr. Barry Rawn
Delft University of Technology
Thank Simon. Observe wind power is external driver that makes power engineering exciting.
Why? Because its differences make us revisit the basic assumptions of our systems.

2. Prospects: Perspectives: This talk is about: substantial helpful1
This talk is about:
Prospects:
substantial helpful
effect on climate
major component of
energy security
.. they are different.
long term price stability
re-think way we run
power system
Perspectives:
The myths.
Neither impossible nor difficult: just different.
policy makers and lawyers
investors
..they are many.
electricity grid and market operators

3. “stabilization triangle” substantial helpful effect on climate2
Global: the
“stabilization triangle”
substantial helpful
effect on climate
European level:
About 25-30% of efforts
Image credit: cmi.princeton.edu
Two things: think in GT, and consider possibilities of existing technology
200 Gt, in next 50 years:
Each wedge: GT/year
Install 2TW of wind;
provide about 5 PWh

4. We’re coupling our energy system to climate patterns, and to 3
We’re coupling our energy system
to climate patterns, and to
weather patterns.
Variable,
but predictable.
Regional-but
renewable
Image credit: The Atmosphere, 8th edition,
Lutgens and Tarbuck, 8th edition, 2001

5. Will climate change affect wind power projects?4
Will climate change affect wind power projects?
Michelangeli and Loukos, 2007
Rough reasoning anticipates
future reduction in yield…
..detailed models confirm.
Effect varies over globe;
depends on local features;
hard to predict.
Lorenz and DeWeaver, 2007

6. Will wind power projects cause climate changes? wind energy conversion
requires momentum
transfer.
1 .tradeoff, slow down
2. corkscrew-> mikxing 5

7. Will wind power projects cause climate changes? Wake effect:6
Will wind power
projects cause
climate changes?
Brand 2009
minimum safe distance (2-10% deficit): order of tens of kilometers
the recovery distance (1%
Deficit): hundreds of kilometers.
Christiansen and Hasager 2005
Wake effect:
becoming of
legal interest
Brand 2009

8. Will wind power projects cause climate changes?7
Will wind power
projects cause
climate changes?
Keith, 2004
Change global mean temperature?
Detectable but negligible compared to
anthropogenic forcing.
Takel, 2011
Wind power affects
crops, local weather?
First indication:
helpful or neutral;
but research just starting

9. Is there even that much wind power?8
Is there even that much wind power?
Physical Potential
Technical Potential
Economic Potential
Hoogwijk 2004

10. Is there even that much wind power?9
Is there even that much wind power?
Technical: 96 PWh/year,
Economic: 53 PWh/year at 0.13 €/kWh
21 PWhr/year at €/kWh
versus 15 PWh/year global electricity consumption
of global electricity consumption
Hoogwijk 2004

11. Is there even that much wind power?10
Is there even that much wind power?
Many regions have resource exceeding consumption, costs differ.
Hoogwijk 2004
3 PWh/year
European electricity consumption in 2008:

12. Is there enough money to build it all?11
How much has been built?
As of 2004, about 0.05% of the economic potential was developed
As of 2010: perhaps 0.4%.
Source: GWEC
Growth rate of last 5 years: ~27%
(doubles every ~3 years)
Is there enough money to build it all?
Exponential growth: it’s an outcome
Global: 0.5T USD a year to meet 450 PPM
(vs bond market 90 T USD)
Europe: to meet EU targets, billion a year
(vs bond market 23 T, GDP of Europe: 16T)
Trend in pension fund investment in infrastructure: estimated at 1 T a year

13. Addressing investment risk: significant deployment barrier12
Addressing investment risk: significant deployment barrier
Samec 2011
Sources of risk: resource uncertainty, inflation, construction delay
Mitigation instruments: wind derivatives, loan guarantees, construction insurance

14. Generation mix: limits and changes in thinking13
Generation mix: limits and changes in thinking
30% renewable energy scenario studied in North America: (image credits NREL)
Total system load:
wind
coal
nuclear
Inflexible generation can impose minimum generation limit:
Storage or transmission needed to avoid curtailment
“Cycling” of units uncomfortable;
Need emerges for new types

15. Variability and Uncertainty14
Variability and Uncertainty
Provision always
existed for changes:
both anticipated
and unexpected.
Image credit:Makarov et al, PNNL-19189, 2010
Madsen and Pinson: imm.dtu.dk, 2009
This applies to “msot of the time”
Wind power forecasts a common tool in control rooms.

16. controllable wind power, because forecasts not15
Example:
Denmark
First to pioneer
controllable wind power, because forecasts not
perfect.
Image credit:
upwind.eu
“Soft Storm Transition” or “Storm Control”:
Farm-level control using pitch
Wind speed
(m/s)
Power production
(MW)
minutes
Image credit:
upwind.eu
Image credit: Gijs van Kuik, TU Delft, DUWIND

17. 16
Example:
Denmark
Image credit: Energinet

18. Switched Power Electronics Interfaces17
Switched Power Electronics Interfaces
Synchronous Machine (traditional)
simple, fixed, strong
Power Electronic Interface
Complex, flexible,
relatively fragile

19. Example: Ireland 18 An island electric power system
Must be mostly self-sufficient, even for short periods
Contingency event:
Loss of big generator,
or introduction of
big load
Hirvonen 2003
In first instances:
Need to use energy
stored in system’s
rotating masses

20. 70-80% Example: System Ireland collapses 60-70% immediately System19
70-80%
System
collapses
immediately
Example:
Ireland
60-70%
System
splits in half,
collapses.
2008/2009
range of
operation
Wind turbine
rotors not
forced to be
synchronous:
->
several
related problems
Eirgrid, All-Island TSO Facilitation of Renewables Studies, Final Study Report

21. 20
Example:
Spain
Electricity grid behaviour during a fault (lightening, tree, etc)
generators can help by
staying connected,
in spite of voltage transient:
formerly allowed
disconnect level
new requirement
typical transient
Image credit: RED Eléctrica España
Bömer 2011

22. 21
Example:
Spain
Wind power production behaviour *before* “ride-through” requirement: nuclear sized dips.
Image credit: RED Eléctrica España
How are the worst situations avoided?

23. 22 ! 
Image credit: RED Eléctrica España

24. Wrapping up: From all these perspectives, which ideas to take home ?23
Wrapping up:
From all these perspectives,
which ideas to take home ?
We’re coupling our energy system
to the climate in a new way.
Variability and uncertainty in our power system: not a new thing, but changes can be expected
Imp notes:
Own animal:
-converter interface: relatively fragile; excellent control
-within available resource: extremely flexible
-composition of many units can cause complexity, but also brings robustness. -
Generation is always a mixture; wind power plants their own animal offering challenges but also benefits