The European power system has changed considerably in the last 15 years. The liberalisation and unbundling of the electricity market has led to increased international power flows and reduced influence of the system operators. Meanwhile, renewable and other small-scale uncontrolled and variable energy sources are being installed in the system.
In today’s session the effects of these changes on the power system will be discussed. They will be analysed along with how investments in the transmission system can help, and the different options available. Special attention will be given to power flow controlling devices and HVDC as they are getting much attention in the power industry at the moment.
* Effects of wind energy in the international power system
* Investments in the transmission system, why are they lacking, what the options are (overhead, cable, etc.)
1. Mini-Course on Future Electric Grids
Part 1 of 2
Dirk Van Hertem — Dirk.VanHertem@ieee.org
Electric power systems
Electrical engineering department
Royal Institute of Technology, Sweden
February 22, 2010
K.U.Leuven (Belgium) KTH, Stockholm (Sweden)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 1 / 29
2. 1 Introduction
Course overview
2 Variable flows in the system
Before liberalization and the rise of renewables
International market environment
More renewable energy generation
Effects on the system
International setting
Common misunderstandings about wind power
3 Investments in the power system
Need for investments
Investments to integrate renewables
Investment technologies to increase transmission capacity
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 2 / 29
3. Introduction
1 Introduction
Course overview
2 Variable flows in the system
Before liberalization and the rise of renewables
International market environment
More renewable energy generation
Effects on the system
International setting
Common misunderstandings about wind power
3 Investments in the power system
Need for investments
Investments to integrate renewables
Investment technologies to increase transmission capacity
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 3 / 29
4. Introduction Course overview
Who am I?
Master in engineering from KHK Geel, Belgium
Master of science in engineering from K.U.Leuven, Belgium
PhD in engineering from K.U.Leuven, Belgium
Currently Post-Doc researcher at the Royal Institute of Technology,
Stockholm, Sweden
Active member of both IEEE and Cigré
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 4 / 29
5. Introduction Course overview
Course overview and objectives
Overview Part 1
New situation in the power system
1 Liberalization of the market
2 Increased penetration of smaller, variable energy sources
3 No single authority in Europe
4 Lacking investments in the transmission system
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 5 / 29
6. Introduction Course overview
Course overview and objectives
Overview Part 2
International coordination in the power system
How this cooperation can benefit and obstruct
Power flow controllers
Coordination and power flow controllers
The future “supergrid”. . .
. . . and the road towards it
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 5 / 29
7. Introduction Course overview
What it is about and what not
Not the grid of 2050
Main focus is Europe
Not about smart grids (or not specifically)
About transmission and not distribution
Mainly from a grid operator point of view
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 6 / 29
8. Variable flows in the system
1 Introduction
Course overview
2 Variable flows in the system
Before liberalization and the rise of renewables
International market environment
More renewable energy generation
Effects on the system
International setting
Common misunderstandings about wind power
3 Investments in the power system
Need for investments
Investments to integrate renewables
Investment technologies to increase transmission capacity
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 7 / 29
9. Variable flows in the system Before liberalization and the rise of renewables
The old system
Before liberalization:
Mostly vertically integrated companies
All operational issues were within one company
Both generation and transmission investments were done in one company
and coordinated
Synchronous system to increase security
Limited international trade, and mostly long-term contracts
Before massive introduction of renewable energy sources and
distributed generation:
Centrally planned generation
Centrally controlled
Focus on high availability
Bigger is better (economy of scale)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 8 / 29
10. Variable flows in the system International market environment
Energy is traded
Electric energy is traded on the market in blocks of 1 or more hours
Where different bids can come from different generators
These bids are also from neighboring systems
When a single company offers a block, this is not necessarily from the
same generator
This causes variable flows throughout the grid
Including transnational flows
Physical flows are not equal to contracted flows
A higher reserve margin is needed
The ramping of generators is not immediate
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 9 / 29
11. Variable flows in the system More renewable energy generation
Increased penetration of smaller, variable energy sources
Traditional power plants
Bigger is better, more economic
Size is limited by technology (GW power plants)
Generally investments and operation by centrally controlled, big
companies
Renewables, CHP and new generator types emerged
Generation units as small as 1 kW
Not centrally planned or controlled
Further increase to be expected in the future (Electrical cars?)
Uncertain generation pattern. . .
3
Pwind = f (vwind ), no light during the night and clouds,. . .
CHP output is usually dependent on heat process
. . . and consequently uncertain flows
Balancing of wind is a problem for some countries
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 10 / 29
12. Variable flows in the system More renewable energy generation
A strong increase in power from renewable energy
Figure: Share of electricity from renewable energy Figure: The development of wind energy in
to gross electricity consumption. (source: Europe shows an almost exponential increase
Eurostat) (logarithmic scale). (source: Eurostat)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 11 / 29
13. Variable flows in the system More renewable energy generation
A strong increase in power from renewable energy
Increased installed wind power in Europe
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 11 / 29
14. Variable flows in the system More renewable energy generation
A strong increase in power from renewable energy
Installed capacity of wind in Europe
(source EWEA)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 11 / 29
15. Variable flows in the system More renewable energy generation
A strong increase in power from renewable energy
Larger part of new generation is from variable sources
(source EWEA)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 11 / 29
19. Variable flows in the system Effects on the system
Effects on the system
Frequency deviations due to hourly changes in generation and limited ramp
rates (source UCTE)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 12 / 29
20. Variable flows in the system Effects on the system
Effects on the system
Frequency deviations in Nordel increase in general
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 12 / 29
21. Variable flows in the system Effects on the system
Unpredictability of wind power: international context
8000
Actual
6000
Wind generation (MW)
4000
2000
0
−2000
0 5 10 15 20 25 30
Day of the month
Real, estimated and mismatch wind generation in November 2007 in the
E.On-Netz grid (Now transpower, part of TenneT), Day-ahead data for every
15 min
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 13 / 29
22. Variable flows in the system Effects on the system
Unpredictability of wind power: international context
8000
Actual
Expected
6000
Wind generation (MW)
4000
2000
0
−2000
0 5 10 15 20 25 30
Day of the month
Real, estimated and mismatch wind generation in November 2007 in the
E.On-Netz grid (Now transpower, part of TenneT), Day-ahead data for every
15 min
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 13 / 29
23. Variable flows in the system Effects on the system
Unpredictability of wind power: international context
8000
Actual
Expected
Difference
6000
Wind generation (MW)
4000
2000
0
−2000
0 5 10 15 20 25 30
Day of the month
Real, estimated and mismatch wind generation in November 2007 in the
E.On-Netz grid (Now transpower, part of TenneT), Day-ahead data for every
15 min
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 13 / 29
24. Variable flows in the system Effects on the system
Unpredictability of wind power: international context
+100 MW 2,9 %
16,3 %
-
3,5 %
?
-100 MW
3,9 %
14,2 % 6 6 12,8 %
Wind is predominantly located in the north. . . and is balanced in the south
National problem can have international consequences
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 13 / 29
25. Variable flows in the system Effects on the system
Unpredictability of wind power: international context
Unpredictability of hydro
Runoff variations in the power-generating rivers (source: Swedenergy)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 13 / 29
26. Variable flows in the system International setting
Difficult international setting
Every TSO, generator, regulator,. . . on his own
There is no single European authority: an international patchwork
Each has his own responsibilities and tasks
No common authority and no common goal
European Union Synchronous zones
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 14 / 29
27. Variable flows in the system International setting
Difficult international setting
Every TSO, generator, regulator,. . . on his own
There is no single European authority: an international patchwork
Each has his own responsibilities and tasks
No common authority and no common goal
ETSO TSOs
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 14 / 29
28. Variable flows in the system International setting
Difficult international setting
Every TSO, generator, regulator,. . . on his own
There is no single European authority: an international patchwork
Each has his own responsibilities and tasks
No common authority and no common goal
Third package
3rd package proposes some changes
Full (further) unbundling
Establishment of ENTSO-E (European Network of Transmission System
Operators for Electricity)
ETSO + synchronous zones (UCTE, Nordel, Baltso, UKTSOA, ATSOI)
Establishment of an ACER (Agency of energy regulators) to get ONE
regulatory body with binding decision powers to complement national
regulators
Not a direct successor of ERGEG/CEER
Cross-border cooperation and investments should be promoted
More transparency and solidarity
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 14 / 29
29. Variable flows in the system International setting
Difficult international setting
Every TSO, generator, regulator,. . . on his own
There is no single European authority: an international patchwork
Each has his own responsibilities and tasks
No common authority and no common goal
Steps towards a IEM are being taken: ERI + Third package
Regional coordinated grids ENTSO-E: synchronous zones + ETSO
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 14 / 29
30. Variable flows in the system Common misunderstandings about wind power
Common misunderstandings about wind power
Wind integration is a hot issue, and much debated
There are both people in favor and against wind
A lot of misconceptions exists
(source: Wind Power Myths Debunked; M. Milligan, K. Porter, E. DeMeo,
P. Denholm, H. Holttinen, B. Kirby, N. Miller, A. Mills, M. O’Malley,
M.Schuerger, L. Söder; Power and Energy Magazine; Nov/Dec 2009)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 15 / 29
31. Variable flows in the system Common misunderstandings about wind power
Common misunderstandings about wind power
Power system operation with variable wind?
Variability is something operators can work with, as loads also vary
Variability is lower when more wind generators are grouped, especially
when spread geographically
Forecasting is possible and techniques get better
Answer: yes possible, but higher reserves are needed on the
generators (at a cost + international influence)
Capacity credit?
Capacity credit: sufficient installed capacity to cover load
Planning takes normally a reserve margin for generation (outages etc)
But can we count on wind?
Answer: yes, but not at full capacity. Capacity margin should be
calculated through LOLE (loss of load expectancy)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 15 / 29
32. Variable flows in the system Common misunderstandings about wind power
Common misunderstandings about wind power
What are the chances on no wind at all?
. . . or simultaneous shut down at too high wind speeds
Aggregation again lessens the problems
Current forecasts are good enough to start up alternative energy
generation in due time
Difficult to predict wind?
Amplitude and shift
Long time horizons are more difficult to predict than short
Updating of forecasts and scheduling is needed
Forecast errors need to be integrated in predictions
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 15 / 29
33. Variable flows in the system Common misunderstandings about wind power
Common misunderstandings about wind power
Expensive to integrate wind?
Integration costs money
But these costs can be integrated
Also here balancing over large areas helps
New transmission needed?
Any generation needs transmission
Distributed wind might initially reduce the need for grids
Remote locations need to be connected (e.g. new offshore always
needs new lines)
Similar as connection of hydro in 60’s and 70’s
Balancing/variability requires more grid than traditional generation for
the same amount of energy delivered
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 15 / 29
34. Variable flows in the system Common misunderstandings about wind power
Common misunderstandings about wind power
Wind power and backup generation: burning fossil fuels?
Backup (reserves) are needed
In practice this is done through existing generation not working at 100 %
capacity or controllable generation (mostly hydro)
→ No dedicated backup
System-wide, CO2 is saved and fossil fuel consumption decreased
(although single machine efficiency might be lower)
Storage is needed?
The grid itself works as a storage device by balancing different variable
energy sources
Storage might be interesting from an economical point of view,
especially at very high levels of penetration
Storage must compete with wind curtailment, new transmission lines
and generation dispatch
Limited availability of useful storage technologies
Hydro (pumped or controlled flow) best storage
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 15 / 29
35. Variable flows in the system Common misunderstandings about wind power
Common misunderstandings about wind power
Does wind generation measure up taking capacity factor into
account?
This is a purely economic consideration: e/kWh
Is there a limit to the accommodation of wind?
There is an economic limit (linked to willingness to pay for a “greener”,
CO2 -free society or a more reliable energy supply)
Dependent on the grid
Technically there is no clear limit as both active (through curtailment)
and reactive power can be controlled
Control of the wind generators and the system as a whole needs to be
adapted in order to accommodate a high penetration of wind
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 15 / 29
36. Investments in the power system
1 Introduction
Course overview
2 Variable flows in the system
Before liberalization and the rise of renewables
International market environment
More renewable energy generation
Effects on the system
International setting
Common misunderstandings about wind power
3 Investments in the power system
Need for investments
Investments to integrate renewables
Investment technologies to increase transmission capacity
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 16 / 29
37. Investments in the power system Need for investments
Lacking investments in the power system
In the vertically integrated system, investments were “easy”
Centrally controlled with government support
Security above everything else: overinvesting is ok
Generation investments and transmission investments were planned
within one organization
Now investments in transmission lines are subject to regulatory approval
Regulator is usually focussed on reducing transmission tariffs
Regulators consider mainly issues within their member state
Policy and regulations (environmental, building permits,. . . ) have
become more stringent, complex and especially time consuming
Difficult investment climate due to uncertain investments in generation
and uncertain politics/regulations
Heavy public opposition against any new investment (environmental,
public, political, health,. . . )
NIMBY, NIMTO, BANANA, CAVE,. . .
According to ETSO: . . . in some countries, not a single overhead power
line exceeding five kilometres has been built in the last 10 years”
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 17 / 29
38. Investments in the power system Need for investments
Lacking investments in the power system
In the vertically integrated system, investments were “easy”
Centrally controlled with government support
Security above everything else: overinvesting is ok
Generation investments and transmission investments were planned
within one organization
Now investments in transmission lines are subject to regulatory approval
Regulator is usually focussed on reducing transmission tariffs
Regulators consider mainly issues within their member state
Policy and regulations (environmental, building permits,. . . ) have
become more stringent, complex and especially time consuming
Difficult investment climate due to uncertain investments in generation
and uncertain politics/regulations
Heavy public opposition against any new investment (environmental,
public, political, health,. . . )
NIMBY (not in my backyard), NIMTO (not in my term of office), BANANA
(Built absolutely nothing anywhere near anything), CAVE (citizens against
virtually everything),. . .
According to ETSO: . . . in some countries, not a single overhead power
line exceeding five kilometres has been built in the last 10 years”
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 17 / 29
39. Investments in the power system Need for investments
Investments over the last decades
DSO data
The grid was built about 40 years ago
sources: resp. RWE, PBPower/IBM and KEMA
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 18 / 29
40. Investments in the power system Need for investments
Cross border investments
Why cross-border investments are especially problematic
Cross-border connections are traditionally weak: previously only
needed for synchronization and in emergencies
Price differences between zones specifically show themselves as
congestion on borders
Uncertainty about what is happening abroad (limited knowledge of the
outside grid development)
Different policies and requirements across borders
Paradox of investing in transmission lines for other beneficiaries
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 19 / 29
41. Investments in the power system Need for investments
Paradox of investing in cross-border lines
Paradox of investing to relieve congestion
A B
A is congested because of
north-south flow in B
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 20 / 29
42. Investments in the power system Need for investments
Paradox of investing in cross-border lines
Paradox of investing to relieve congestion
A B
A B
Investing in A is ‘bad’ solution for
A is congested because of
A: local investment for foreign
north-south flow in B
problem
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 20 / 29
43. Investments in the power system Need for investments
Paradox of investing in cross-border lines
Paradox of investing to relieve congestion
A B
Investing in B would be best, but
no reason for B (or the regulator
of B) because no local problem
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 20 / 29
44. Investments in the power system Need for investments
Paradox of investing in cross-border lines
Paradox of investing to relieve congestion
A B
A B
Investing in B would be best, but
no reason for B (or the regulator PFC can help
of B) because no local problem
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 20 / 29
45. Investments in the power system Need for investments
Result: Bottlenecks in the system
Figure: Electricity Projects of European Interest (source: PIP:
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=COM:
2006:0846:REV1:EN:PDF)
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 21 / 29
46. Investments in the power system Need for investments
Obstables for PIP projects according to TEN-E
PIP= Priority Interconnection Plan
Obstacle # Projects
1 Electromagnetic fields (EMF) 11
2 Environmental issues 9
3 Visual impact 7
4 Densely populated/Urban/Rural areas 7
5 Grid issues 9
6 Dependency on other project(s) 2
7 Authorization procedure and legal framework 12
8 Identification of cross-border points 3
9 Commercial Problem 3
10 Difficult terrain and weather 4
11 No perception of supra-national or European perspective 2
Table: Obstacles according to the priority interconnection plan of TEN-E
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 22 / 29
47. Investments in the power system Investments to integrate renewables
Investing to accommodate renewables
Any generation needs transmission
Renewables often located at remote locations
This is certainly the case for wind (NIMBY)
. . . and evident for offshore
Variability of wind makes that on average more grid is needed for the
same load
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 23 / 29
48. Investments in the power system Investments to integrate renewables
Power from the sea: Belgian example
Concessions:
C-power: 216-300 MW, 27 km
Belwind: 330 MW, 42 km
Eldepasco: 180-252 MW,
38 KM
More coming/being processed
Dirk Van Hertem (Electric Power Systems, KTH) Mini-course on Future Electric Grids (1/2) 22/02/2010 24 / 29