Technical Challenges of Integrating Large Amounts of Wind Power onto Electricity

Grids

Professor Mark O’MalleyDirector: Electricity Research Centre (ERC)

http://ee.ucd.ie/erc/

UNSWSydney3 Feb 05

Summary

• Wind industry in Ireland

• The moratorium

• ERC - wind related research activities

• Conclusions

Professor Mark O’Malley• Research Interests

– Modelling, control and optimisation - Electrical Power Systems & Biomedical Engineering

• Research Team– Two postdocs, one administrator, 7 PhD students– $0.5M per year

• Electricity Research Centre (ERC)– Electricity Supply Board, ESB National Grid, Cylon Controls, Commission for

Energy Regulation (CER), Airtricity, Viridian ?, Sustainable Energy Ireland (SEI), Economic and Social Research Institute (ESRI), Department of Communications Marine and Natural Resources (DoCMNR)

– Queen’s University Belfast (QUB), University of New South Wales (UNSW), University of Washington (UW), University of Manchester Institute of Science and Technology (UMIST), University College Cork (UCC), ILEX Energy Consulting, AREVA

• Renewable Energy Development Group (REDG)– DoCMNR & Indstry– Chair of Technical Group

Wind industry in Ireland

European Synchronous Power SystemTotal Generation Capacities

Nordel

83,000MW

UCTE

550,000MW

Ireland(incl NI)

7,000MW

EnglandWales

Scotland76,000MW

Wind Generation as % of Total Installed Capacity across each European Synchronous Power System

0%

2%

4%

6%

8%

10%

12%

14%

16%

Iceland England WalesScotland

Nordel Ireland (incl NI) UCTE

Wind Generation as % of Total Installed Capacity across each European Synchronous Power System

0.0% 0.7% 0.9%3.3% 4.1%

0%

2%

4%

6%

8%

10%

12%

14%

16%

Iceland England WalesScotland

Nordel Ireland (incl NI) UCTE

Operational Contracted Live Offers Applications

Wind Penetration

+64 %225137Ireland

+26 %39,43431,234Total

+67 %880524Pacific

170

166

2,705

6,678

28,610

Start 04 (MW)

+14 %149Middle East & Africa

+19 %139Latin America

+24 %2,184Asia

+37 %4,881North America

+23 %23,220Europe

% ChangeStart 03 (MW)

Challenges for Ireland• Irish Electricity System

– Small but significant– One dc connection– A model for bigger

systems– Rapidly increasing

amounts of wind• At the forefront of wind

integration issues

Support mechanism• Alternative Energy Requirement (AER)

– 15 year power purchase agreement from ESB Public Electricity Supplier (PES)

– Auction process– Not coordinated with grid connection,

planning permission etc.• Merchant plant• Other suppliers

The moratorium

Wind in Ireland• Dec 3rd 2003 Moratorium on Wind connections• Transmission System Operator Concerns

– Increase too rapid– Relatively small size (Island System)

• Technical issues– Grid code for wind, voltage control– Grid code derogations– Fault ride through – Validated wind turbine models – for dynamic studies– Operations, forecasting & ancillary services

Wind in Ireland• Wind in Republic (July 04)

– 240 MW - connected– 600 MW – signed agreements– 1600 MW – applications

• Applications & support mechanism are not synchronised

• Process is now hopelessly blocked• Potential for stranding of assets• Clustering approach being proposed

Fault

Voltage Profile– Red < 15 %– Yellow 15 – 50

%– Green 50 – 80 %

Moratorium on wind • Lifted October 2004

• New Grid Codes for wind– Fault Ride Through

• Wind Turbine Generator Models– Validation– http://www.eirgrid.com/EirGridPortal/uploads/Regulation%20and%20Pricing/Appendix-24th%20January.pdf

• Non dispatchable nature– Constraining off

• Connection process is still blocked

Renewable Energy Development Group

• May 2004 - Chaired by DoCMNR

• Members: Regulator, ESB National Grid, ESB PES, Irish Renewable Energy Industry, Northern Ireland, Sustainable Energy Ireland, Economic and Social Research Institute, Electricity Research Centre

• Short Term Analysis Group – Technical & Policy

• Short Term Targets (2010) & Long Term Targets (2025)

• Short Term Report due out Feb 2005

ERC wind related research

ERC wind related research

• Reserve requirements for significant wind power penetration - Ronan Doherty

• Wind Turbine Generator Modelling – Alan Mullane

• Frequency Control and Wind Turbine Technologies - Gill Lalor and Alan Mullane

• Optimal Allocation of Embedded Generation –Andrew Keane

• Emissions and Wind Power – Eleanor Denny

Reserve requirements for significant wind power penetration

ILEX Energy, UCD, QUB and UMIST, “Operating reserve requirements as wind power penetration increases in the Irish electricity system”, Sustainable Energy Ireland, http://www.sei.ie/uploads/documents/upload/publications/Ilex-Wind-Reser_rev2FSFinal.pdf, 2004.

Forecast error• As capacity increases, diversity reduces forecast

error– diversification effectively maximised by 800MW

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

20%

0 MW 200MW

400MW

600MW

800MW

1000MW

1200MW

1400MW

1600MW

1800MW

2000MW

Installed Wind Capacity

Stan

dard

dev

iatio

n of

win

d er

ror Fast (1.25 min)

Slow (30 min)1 Hour4 Hour

Reserve targets

250 MW

300 MW

350 MW

400 MW

450 MW

500 MW

550 MW

600 MW

650 MW

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Res

erve

Tar

get

Fast (1.25 min)Slow (30 min)1 Hour4 Hour

Installed Wind capacity (MW)

Reserve requirements for significant wind power penetration

• In Ireland benefits of diversification will saturate at 800 MW

• Very little additional short term reserve required

• Larger amounts of slower reserves needed

Wind Turbine Modelling & Frequency Control and

Wind Turbine Technology

WTG Modelling, well establisheds emTω →

, well establisheds emTω →

, not well establisheds emTω →

, not well establisheds emTω →

DFIG inertial response• Loss of 300MW generation, RoI system, winter

eve.with approx. 2900MW system demand –Slow DFIG controller

Effect of controller Bandwidth

Comparisons

a – Inductionconstant power

b – Inductionconstant torque

c – DFIG constant power or torque

d – synchronous

Supplementary control

a – Induction constant power

b – Induction constant torque

c – DFIG supplementary control - constant power

–d – DFIG supplementary control - constant torque

System Model

OCGTs

CCGTs

HydroUnits

ThermalUnits

ΣFrequency

+PGEN

ΣLoad-PLOAD Connecting

System

Loss of largest unit summer day - 2010

a – no wind power

b – 2000MW DFIG

c – 2000MW DFIG supplementary control

Wind Turbine Modelling & Frequency Control and Wind Turbine Technology

• DFIGS give little or no inertial response

• With additional wind power penetration of DFIG type – frequency will fall faster and further

• DFIGS can be designed to give an inertial type response

Optimal Allocation of Embedded Generation on Distribution Networks

• Linear programming formulation

• Objective to maximise embedded generation on existing distribution network

• Constraints: Voltage, Short Circuit, Short Circuit Ratios, Equipment Ratings

Optimal grid development

Generation Capacity

0

32

0

11

4 4

65

22

6

3

0

5

10

15

20

25

A B C D E Total

Bus

Gen

erat

ion

(MW

)

6MW at Bus E

Optimal Allocation

Optimal Allocation of Embedded Generation on Distribution Networks

• Objective optimisation technique for optimal allocation of embedded generation on the distribution network

• Avoids “network sterlisation”

• Being improved to take into account development of the distribution network

Wind Generation, Power Systems Operation and Emissions Reductions

• Dispatch model

• Data from ESB Power Generation

• Two different operational strategies– Fuel saver– Wind forecast

Emissions with wind 2003

Peat Scenarios

Wind Generation, Power Systems Operation and Emissions Reductions

• Emmissions do not necessarily reduce with additional wind generation

• Other policies have a bigger impact– Carbn Tax– Peat

Other challenges

• Markets– All island market– Support mechanisms

• Optimal plant mix– Wind & backup

• Government– Energy policy

Selected PublicationsPublished

Doherty, R., Lalor, G. and O’Malley, “Frequency Control in Competitive Electricity Market Dispatch”, IEEE Transactions on Power Systems”, in press, 2005.

Mullane, A. and O’Malley, M.J., “The inertial-response of induction-machine based wind-turbines”, IEEE Transactions on Power Systems, in press, 2005.

Doherty, R. and O’Malley, “New approach to quantify reserve demand in systems with significant installed wind capacity”, IEEE Transactions on Power Systems”, in press, 2005.

Bazilian, M., Denny, E. and O’Malley, M.J., “Challenges of Increased Wind Energy Penetration in Ireland”, Wind Engineering, vol. 28, pp. 43-56, 2004.

Dillon, J., Walsh, M. and O'Malley, M. J., "Novel initialisation of the augmented Hopfield network for improved generator scheduling", IEE Proceedings Generation, Transmission and Distribution, Vol. 149, pp. 593 – 599, 2002.

Flynn, M., Sheridan, P., Dillon, J. and O'Malley, M. J., "Reliability and reserve in competitive electricity market scheduling", IEEE Transactions on Power Systems, Vol. 16, pp. 78 – 87, 2001.

Flynn, M., Walsh, M. and O'Malley, M. J., "Efficient use of generator resources in emerging electricity markets", IEEE Transactions on Power Systems, Vol. 15, pp. 241 – 249, 2000.

In review

Lalor, G., Mullane, A., and O’Malley, “Frequency Control and Wind Turbine Technologies”, IEEE Transactions on Power Systems”, in review, 2005.

Lalor, G., Ritchie, J., Flynn, D. and O’Malley, “The Impact of Combined Cycle Gas Turbine Short Term Dynamics on Frequency Control”, IEEE Transactions on Power Systems”, in review, 2004.

Denny, E., and O’Malley, “Wind Generation, Power System Operation and Emissions Reduction” IEEE Transactions on Power Systems”, in review, 2004.

Keane, A and O’Malley, “Optimal Allocation of Embedded Generation on Distribution Networks”, IEEE Transactions on Power Systems”, in review, 2004.

Conclusion• Interesting times ahead in wind industry

• Challenges

• Way forward– Integrated research program– Scientific – validation– Policy dimension

Acknowledgements• ERC Funders• ERC Research Team

– Dr. Alan Mullane– Ms. Gill Lalor– Mr. Ronan Doherty– Ms. Eleanor Denny– Mr. Andrew Keane– Mr. Garth Bryans

• Hugh Outhred, CEEM, UNSW