Indispensable requirements for wind farms to contribute to the stability and operability of the system

Transcription

1 3rd Workshop of the International Feed-in Cooperation Madrid, November 23rd and 24th, 2006 Indispensable requirements for wind farms to contribute to the stability and operability of the system Ralf BISCHOF Managing Director German Wind Energy Association Bundesverband WindEnergie (BWE)

2 Basic preconditions for higher shares of electricity from renewable energy sources (RES) 1. Building new RES capacity: Reasonable return on investment for investors bearing in mind the risks of price and grid access 2. Stability and operability of the system: Re-design of grid and market organisation Focus of this presentation: Contribution of wind farms resp. wind energy converters (WEC)

3 Comparison Windenergy in Spain and Germany Quelle: DENA

4 General grid and system issues Quelle: DENA

5 Focus of this presentation 1. Requirements for low shares of wind energy in the system (WEC capacity < minimum system load) 2. Requirements for high shares of wind energy in the systems (WEC capacity > minimum system load)

6 Onshore wind scenario for Germany Stand: Wind onshore capacity in Germany - BWE Scenario capacity / M repowering (net) new year

7 Germany Minimum system load: about 40 GW 2006 WEC capacity: 20 GW low share 2020 WEC capacity: >40 GW high share

8 1. Requirements for low shares of wind energy in the system (WEC capacity < minimum system load) System services can be provided by residual conventional power plants But some contributions of wind farms are indispensable already now - Reactive power (decentral!) - Congestions management (transmission level) - Low voltage ride through = LVRT - Reaction to disturbances (e.g. under-/overfrequency) - Some examples

9 Stand: Simple reactive power requirement: limits for power factor Germanischer Lloyd WindEnergie GmbH

10 Advanced requirement: reactive power voltage regulation

11 Congestion management For economic reasons it makes no sense to build a grid feasible to absorb even the last kilowatthour, especially in case of grid disturbances. WECs have to contribute to congestion management Example Rare, extreme situations: Very strong Wind and very low load (e.g. on Christmas)

12 Rare situation: more than 80% of name plate capacity Stand:

13 LVRT: Voltage dip 2015 near Hamburg Loss of >3.000 MW Wind Stand:

14 LVRT: Grid code requirements for new (and old?) turbines Quelle: DENA

15 Disturbance : Overfrequency in North/East-UCTE

16 Disturbance : Overfrequency in North/East-UCTE

17 Disturbance : Reaction of WECs in E.on grid Quelle: DENA

18 2. Requirements for high shares of wind energy in the systems (WEC capacity > minimum system load) System services can not be provided by conventional power plants WECs have to provide system services to a large extent (when the wind blows) - frequency - acitve power control (primary service) - balancing power (secondary service) - full voltage - reactive power control - Restart the system after black-outs (black start capability) -

19 Is 100% wind in the grid feasible?

20 Yes! 2006 in West-Denmark (Feed-in-system) Quelle: DENA

21 Results of German grid study (2015) Quelle: DENA GW Minimum Load Peak Load Wind 2006 Wind 2015 Dena RE total 2015 Dena

22 Additional balancing capacity required Stand:

23 Balancing power from wind? - Reasons Wind induces extra balancing requirements Should it be (at least to some extent) covered by wind itself? Possible reasons are: Extra balancing necessary only when the wind blows Pumped storage hydro limited (7.000 MW for Germany) WECs can compared to conventional thermal plants react faster

24 Balancing power from wind? - Costs Down-regulation: curtailment of maximum possible output of wind farms on demand Costs for wind power not fed in the grid during down-regulation Up-regulation: Steady curtailment of maximum possible output of wind farms makes it possible to deliver up-regulation Costs for wind power not fed in during whole period of curtailment, thus considerable higher than for down-regulation

25 New E.on grid code: Reduction of active power in case of overfrequency not tripping!

26 Evolution of WEC concepts Stand:

27 Example for new concepts: Variable speed WEC with direct coupled synchronous generator

28 Conclusions I Indispensable requirements for wind farms depend on the share of wind energy in the system - among other factors With high shares wind energy has to provide most system services (when the wind blows) No principal barrier for WEC-technology to fulfil these requirements in the future No need for must-run conventional units even with 100% wind in the grid

29 Conclusions II WEC operators and manufacturers need signals in advance to prepare for new requirements Costs for system services (necessary hardware, losses due to curtailment, ) have to be covered by price incentives In Spain incentives for reactive power and LVRT are already in place Feed-in-systems are compatible with increasing grid and system requirements for wind farms Germany could learn from the Spanish example

30 Thank you for your attention

31 Before repowering Windpark Hemme - Mecklenburg-Vorpommern) After repowering

32 Intertripping schemes Stand:

33 200 % Netzausbau, Netz- und Erzeugungsmanagement v = 1,8 m/s Strombelastbarkeit eines Freileitungsseiles mit und ohne Sonneneinstrahlung als Funktion der Umgebungstemperatur DIN EN bei erhöhter Windgeschwindigkeit (Queranströmung 1,8 m/s) C 35 blau: rot: Einfluß der Umgebungstemperatur Einfluß der Sonneneinstrahlung Θ U

34 I I0 Netzausbau, Netz- und Erzeugungsmanagement 180 % C -5 C 15 C 25 C Strombelastbarkeit eines Freileitungsseiles mit und ohne Sonneneinstrahlung als Funktion der Windgeschwindigkeit (Queranströmung) und der Umgebungstemperatur Θ = 35 C 0,6 m/s 1,2 m/s 0 0,5 1 1,5 2 2,5 m/s 3 v

35 Dynamic stability Stand: