Hannele Holttinen

1. The impacts of hourly variations of large scale wind power production in the Nordic countries on the system regulation needs Hannele Holttinen

2. Contents • Wind power production in the Nordic countries: • Variations, smoothing of the variations when geographically distributed generation. Correlation of wind power production • Wind power production versus load: • Wind power production during peak load hours • Variations of geographically distributed wind power production compared to load variations. • What is the effect of large scale wind production on the electricity system? How much wind before more flexibility is needed in the system? How much more flexibility (reserves, transmission, DSM) when wind power increases?

3. Large scale production of wind power • Fluctuating power production • min-hours-days-months-years • average production of 100 MW, varies between 0…400 MW • Many scattered wind parks • smoothing out the variations when large geographical distribution • Production 2…40 hours ahead can be forecasted • for scheduling and exchange (market) • forecasting errors (regulating market) • In-hour variations have to be absorbed by the system

4. How much wind power can electricity system absorb? => How much does the integration cost? • The extra costs of integration depend on wind penetration • X % without extra costs, variations of load will absorb the variations of wind. • XX % with prediction tools, changes in scheduling, changes in transmission (export/import) • > YY % with increasing extra costs for integration • The extra costs of integration depend on electricity system • the amount of flexibility in the system and the cost of increasing it (reserves/transmission/DSM) Cost of wind power integration - the shape of the curve

5. Interconnected Nordic market area. Data for 1999…2001 Finm • Hourly electricity consumption • Finland, Sweden, Norway, Denmark East and West • Hourly wind power production: • Finland: 54 turbines, 21 sites (10 areas scaled to 100 MW each). • Sweden: 13 turbines, 4 sites (3 areas scaled to 100 MW each). • Denmark: real production of 1800…2300 MW in year 2000, East and West total wind production. • Norway: so far only one site • Geographically well dispersed for Denmark and Finland • Only 4 sites in Sweden, upscaling will overestimate variations Tro N. SWE Hel N-M FIN V-M Ø-L V-S S. SWE S-L W.DK E.DK Central Europe

6. Large scale production of wind power (1) • Consumption and wind power production in January 2000: Denmark is real data (~12% wind), for Finland and Sweden data from wind parks is scaled up to about 10 % of yearly electricity consumption from wind.

7. Large scale production of wind power (2) • January 2000 data: Finland, one wind park average power ~1500 MW varies between 0…4000 MW, for total wind average 1500 MW, 30…3500 MW. For 3 Nordic countries: average 4500 MW, 200...9800 MW.

8. Correlations inside a country • Sweden: • 2 sites in Gotland, correlation 0.8 • Gotland vs Southern Sweden: correlation 0.5…0.7 • Finland:

9. Wind data for countries - statistics • Correlation of wind data: If wind production data is not correlated, there can be strong winds in one place at the same time as weaker in another, and together the time series will be smoother. The Finnish and Norwegian wind production is only weakly correlated to that in South-Sweden and Denmark. The winds in South-Sweden and Denmark are correlated. • Descriptive statistics: The average, maximum and minimum production of wind power production scaled to 1000 MW from Finland/Sweden/Denmark and the whole of the 3 countries are seen. The standard deviation tells about the variability of the hourly time series. As a comparison, data from one wind farm scaled up to 1000 MW is shown.

10. Duration:Wind / LoadOne wind farm / Total production of 21 sites Wind / Load Winter / summer

11. Wind power production during peak load hoursFinland, Sweden and Denmark Wind power production during the 10, 50 and 100 highest peak load hours compared to the average production. All numbers: wind power production as % of installed capacity (nameplate capacity). Hourly maximum and minimum values also shown.

12. Wind power production during 10 highest peak load hours in Finland. Years 1999 and 2000. • January 1999 had lower wind speeds than average (production index 71 %). • January 2000 had higher wind speeds than average (production index 112 %). (Production index= calculated production of selected sites compared to average production in January of 11 years 1985…1995. Finnish Meteorological Institute.)

13. Wind in the system: net load = load - wind • Large scale wind power production changes the scheduling of the rest of the production system • Load pattern well known and studied - prediction models for wind power needed, research still going on

14. Variations of large scale wind power production • In one country • the maximum hourly variation is less than 20 % of capacity • the hourly variations are larger than 5 % of capacity during 7-9 % of time • In Nordic countries • the maximum hourly variation is less than 10 % of capacity • the hourly variations are larger than 5 % of capacity less than 4 % of time.

15. Variations of large scale wind power production • 12 h variations: • max ± 95 % of nameplate capacity (Germany, ISET) • max ± 84..92 % of capacity (Finland) • Hourly variations: • max ± 20 % of nameplate capacity (Germany, Denmark, Finland) • 15 min variations: • 8.4 % of of nameplate capacity 6 times per month, max 11 % (Denmark)

17. Hourly variations together with load variations • The need for regulating power in the system increases if wind production causes larger variations to the system than the variations in load today. The short term variations were studied by hourly time series. • This is a preliminary result based on only year 2000 data. Denmark: relatively greater load variations absorb the wind variations. Sweden: data from 4 sites is not representative when scaled up.

18. Hourly variations of wind vs variations of load • Large amount of turbines in small geographic area (Eltra) • Larger geographic area with a small number of turbines (Finland), data upscaled to make 10 % energy penetration • Wind has considerably less effect on net load variations when using real data with large amount of turbines and when initial load variations large

19. Conclusions from first results of hourly data analysis • An effort to estimate the increase in regulation needs for large scale wind power production: • Comparing the hourly load variations without wind to the variations after large scale wind production: hourly variations of net load vs load • Wind production data upscaled --> over estimate the variations • Only 1-2 years of data for each country, Norway still missing • Result: 10 % of wind would increase the need of flexibility by 200 MW in Finland, 50 MW in Denmark, 0 MW in the Nordic area • This applies if no bottlenecks of transmission • In Denmark much less effect of wind to net load variations, because wind is well dispersed, production all over Denmark and because in Denmark load variations are considerably higher than in Sweden and Finland

20. Future work • More data: • Norway, Denmark offshore wind power data 15.5.1999…14.5.2000 • Probabilistic method of combining the variations of wind and load • More statistical analyses: • persistence of production, duration of calms, diurnal distribution of variations (load-wind-net load) • Comparisons with other weather related production forms: • CHP: heat load, temperature correlation of wind. • Hydro and solar power • Longer term variations of wind (4-12-24-36 hours): • wind power in the electricity market, performance of prediction methods