1. Wind in Ireland Integration and cost issues David Milborrow david.milborrow@btinternet.com

2. Author’s previous encounters in Ireland Participated with ESB and other EU utilities in EC-funded studies of wind impacts c.1988 Member of Advisory Panel which selected turbines for Bellacorick, 1990/91 Invited speaker at IWEA Conference, 1996 Adviser to developer based in Co Cork on several windfarms (some now built) since 1994 No permanent affiliations!

3. Scope of talk Assimilating wind  Issues?  Problems?  Costs?  Limits? Extra costs to consumers of adding wind  Sensitivities?

4. Very brief economic interlude Much interest in “Extra cost of renewables” Justified by “External costs” of thermal sources, esp Global Warming

5. Wind and the competition Source: Author, Windpower Monthly, January 2004

6. Levelling the playing field Generation cost comparisons not the whole story Value of wind = Fuel saving value + CAPACITY SAVING value + “embedded benefits” + “green value” - costs of backup Embedded benefits may be positive or negative

7. Who has looked at integration issues? Ireland  ESB (1990), CEGB, and other EU utilities, as part of co- ordinated study  IWEA, “Geographical dispersion of wind in Ireland”, 1999  Garrad Hassan “Impacts” study, 2003  University College, Dublin UK DTI/Carbon Trust Network Study, Intermittency Module, has c.40 worldwide refs back to 1980 Grid operators: Eltra, NGT, Nordel, and US utilities

8. Ireland is different Could be first self-contained electricity system to operate with significant wind input  Denmark is not isolated, but source of useful data, as W Denmark system similar in size  W Denmark currently runs with wind supplying ~20% of consumption  Ties with neighbours mean that effective wind supply is about 10% - still respectable!

9. Integration topics Electricity networks Behaviour of wind plant Assimilating wind into networks  Storage  Capacity credit Transmission issues The future

10. Electricity systems

11. Why integrated systems? Smoothing  Demands  Generation sources Peak/average  House: 15  UK: 1.5 Lower plant margins needed -  House: at least 2*peak Large electricity system: ~1.2* peak All leads to LEAST COSTS

12. Benefits of integrated systems

13. Lessons from western Denmark

14. Scheduling errors

15. Coping with demand variations Generator inertia Frequency & voltage changes Demand management Pumped storage Spinning reserve All can cope with demand increase or decrease

16. Wind characteristics

17. Smoothing makes a difference

18. Smoothing of power swings Time interval: 1 hour

19. Impacts of 20% wind

20. Running electricity systems Managing electricity systems is all about managing risks All estimates of uncertainty come with a range of probabilities, and Uncertainty margins do not add arithmetically – a “sum of squares” law applies

21. Estimating the effects of wind Establish “demand prediction error” for electricity system  UK system, 1 hour ahead, ~ 1.3%, or 400 MW  Irish system: similar %, ~40 MW Estimate “demand prediction” error for wind  Typically ~3% standard error for distributed wind, 1 hour ahead, (“persistence” forecast) Error with wind, based on “sum of squares”

22. Costing the effects of wind Scheduling error with wind enables extra reserve capacity needs to be estimated Establish cost of extra reserve, based on  Reduced efficiency of part-loaded plant  Cost of plant, or,  Market rates

23. Extra back-up capacity

24. Extra costs for backup

25. Storage "Renewables need storage" ?  Rather misleading! Only the intermittent sources "Storage can transform the economics of the intermittent renewables" ? Only if they are very low cost! Several studies have concluded that economics must be studied separately; may be useful to system, or as reserve

26. Capacity credits The “Firm power” issue ++= ?

27. Capacity credits Controversial, despite - Most authoritative studies confirm wind HAS a capacity credit. Includes Ireland Note that definitions a muddle  Some refer to firm power, some to thermal plant  Firm power is less than rated capacity –  For ALL types of plant!!

28. Evaluating capacity credits 2 basic methods:- Establish system LOLP - usually over a year Add wind Subtract firm power to restore original LOLP Or (simplified approach, essentially similar) Examine availability of wind at time(s) of peak demand

29. Capacity credits depend on:- Amount of wind on system Wind speeds Wind turbine types Winds at time of peak demand Utility operating procedures When “normalised” for differences in wind speed, good agreement between most estimates for northern Europe

30. Capacity credits – EU studies

31. Capacity credits for Ireland

32. Capacity credits: monetary values These depend on:- Alternative thermal plant Test discount rates and depreciation times CCGT plant now most common thermal option in EU, costs €500-800/kW Capacity valued at €42-83/kW No "universal" value

33. Benefits of distributed generation Reduced losses Improved reliability, + technical issues Reduced costs if line reinforcements can be deferred or forgotten BUT Siting is important too much DG in remote areas will increase losses or may advance need for line reinforcements

34. Local issues Analysis of Delabole wind farm (UK) by SWEB showed:-  No problems with flicker  Peak demands at local substation coincided with peak output from wind farm  Wind farm output "has major influence in stabilising the 11 kV voltage level" Analysis by P G & E also showed benefits from PV installation

35. Wind integration – conclusions Modest costs for extra reserve  Most studies yield similar results Capacity credits? – Yes, roughly=average power Problem areas?  May be preferable, once wind input exceeds ~10%, to curtail wind output on a few occasions …..but wind will NEVER impose “jolts” on the system comparable with loss of a circuit of cross-channel link

36. Carbon savings from renewables Variety of answers in literature:-  Due to average emissions from plant mix  Due to gas plant which will not be built  Due to emissions from load following (lf) plant In daily operations, wind displaces lf plant New renewables build forces closure of old thermal (usually coal) plant, just as new gas Gas plant not built? How can you be sure? So another argument in favour of 600-850g/kWh from closure of old coal (or oil) plant

37. Extra costs of renewables Increasing interest in “extra costs” as States define renewable targets Estimates of extra costs from various sources Author linked to estimate in Power UK, issue 109: ~0.3p/kWh to consumer bills for 20% wind by 2020 Key issues: Gas prices by 2020 Wind plant costs Price of carbon under ETS

38. Possible future Irish scenarios System MW 5000 6500 Wind %51016122027 Wind MW 50010001500 25003500 Offshore % 253040 4550 Date200520082010 20172025 Source of base data (green): ESBNG; author’s assumptions in red

39. Future gas prices

40. Future wind prices

41. Possible costs to electricity consumers of adding wind

42. Thank you! The End