Large-scale Grid Integration of Wind Power. Experiences from Germany.

Transcription

1 placeholder partner logo Energy Large-scale Grid Integration of Wind Power. Experiences from Germany. Dr. Christine Wörlen, arepo consult WindEnergy Business 2009 Conference Chicago, 10 November 2009

2 Overview Renewable Electricity and Wind Power in Germany The Transmission System in Germany Challenges Real and Potential Solutions

3 WIND POWER IN GERMANY

4 Development of installed capacity

5 BMU energy vision for Germany. Primary energy future development Renewables future development BMU Leitstudie 2009 in 2050: 90% of power from renewables 38% from wind

6 Power generation from renewables. BMU Leitstudie 2009

7 THE TRANSMISSION SYSTEM IN GERMANY

8 Transmission System in Germany (1930)

9 Transmission System in Germany today. NORDEL Tightly meshed Evenly covering all of Germany Bremen Hamburg Historic tasks: Essen Dortmund Hannover Leipzig Berlin Ensuring security of supply by balancing between power plants, and between load and supply, all with different physical characteristics Köln Frankfurt Dresden UCTE (CENTREL) Reducing regulatory and balance power needs Buffering fluctuations through inertia Nürnberg Karlsruhe Stuttgart Additional future tasks UCTE München Transport / wheeling for trade Balancing regional differences Balanding increasing fluctuations

10 Transmission System Setup in Germany 4 zones, part of UCTE 4 grid operators on the 380 kv level: E.on, Vattenfall, RWE, EnBW About 70 regional grid operators on lower voltage levels (220 kv, 110 kv, 20 kv) Operationally unbundled from power generation and distribution Regulated by Bundesnetzagentur Grid operators do not buy or sell power except: power from RE plants under EEG, balance and regulatory power, Loss coverage

11 Grid stability Increased need for balance and reserve power Evacuation / Congestion Temporary Overproduction INTEGRATION ISSUES

12 Reasons for integration issues Intermittency and Fluctuation: Low capacity credit for wind (6 % for Germany) Low-voltage ride-through properties, reactive power issues, other technical aspects Regional concentration in wind-rich areas Congestion. Regionally more electricity produced than consumed. Competition with existing power plant portfolio At times, too much electricity is produced systemwide. Negatively affects price of (balancing) power

13 1.Technical integration issues Low-voltage ride-through, reactive power correction, frequency support, and other technical integration issues have been included in 2009 EEG. A government directive incentivizes wind power plants to deliver system stabilization services (Systemdienstleistungsverordnung - SDLWindV).

14 Leistung [MW] Power in MW 2.Balancing and Reserve Power Online Vortagsprognose previous day s forecast 4-Stundenprognose 4-hour forecast Wind energy lower than predicted positive reserve power Zeit Wind energy higher than predicted negative reserve power

15 2.Balancing and Reserve Power. Fluctuations are always there: changes in load, deviation from load projections, generation failures some power plants need to be able to tune up and down to ensure stability of the grid at all times. Deviation of wind power delivery from projection can be in the order of magnitude of a large power plant s failure, e.g. in E.on s grid zone up to 1000 MW. Solution: Improved wind projections, special trading products. Formerly: covering wind projection deviations from 1day-ahead projection (standard deviation 5.6% of installed wind capacity) with Minutenreserve. Now: special trade products: intraday trading, and Windreserve thus Minutenreserve only applicable to deviation from 2h-ahead-projection (2.7 % standard dev)

16 3.Congestion. In some areas at some times, in Germany, more wind power is produced than grids can absorb. Then grid operators are obliged by law to increase transmission capacity. For a transitional period until the additional capacity is built, grid operators are allowed to impose Einspeisemanagement, i.e. tell wind farms to shut down and stop producing electricity. According to BWE, this can affect up to 10 % of revenues. (German law now provides for compensation. ) Solution: additional incentives for construction and storage.

17 3.Regional overproduction (I). In some regions, more energy is produced than consumed. The transmission grid therefore is transmitting in unusual directions, e.g. from lower to higher voltage levels, or from former sinks into former source areas. This causes wheeling fees to change in unpredictable ways over a number of years.

18 North South gradient in wind generation capacity. Windmonitor (ISET/IWET)

19 3.Regional overproduction (II). In addition, a North-South gradient is made even stronger: more wind and more wind turbines in the North, more new power plants in the North, old power plants everywhere are shut down (nuclear phase-out) New transmission capacity needs to be built. Operational improvements (temperature monitoring) would probably help. dena Grid Study I (2005) has developed a consensus among wind proponents, grid operators and policy makers on what transmission capacity needs to be upgraded and newly built. Energieleitungsausbaugesetz (2009) will speed up permitting processes.

20 dena Grid Study results.

21 New lines no more problems? New lines and regional interconnection (UCTE-wide) also help increase the capacity credit, i.e. the reliable contribution of wind power to the power system. But: NIMBY issues impede most line construction efforts. New lines currently planned are only sufficient to accommodate growth through After that: increasing difficulties with market processes due to systemwide overproduction of electricity.

22 [MW] 4. Systemwide overproduction ~60% of load generated by wind energy Additional export and storage generation demand generation demand generation demand generation demand high load w ithout w ind high load w ith w ind low load w ithout w ind low load w ith w ind conventional power load pump storage wind grid losses import/export Dena gridstudy

23 4.Systemwide overproduction. In periods with low loads and strong winds, too much electricity is generated. Possible Solutions: Export Storage Demand Side Management / Load Shifting (Shut down wind turbines) New business opportunities.

24 Improved Generation Management: Storage Integration of Storage, e.g. Compressed Air Fuel Cell Batteries Fly wheels Condensators Quelle: Fritz Crotogino, KBB Hannover, 2003

25 Improved Generation Management: Virtual Power Plants Joint operation of decentralized power plants, for example wind, biogas-chp, PV, mini- and microhydro Controlled in combination from one central point Currently 3 field trials Quelle: European Technology Platform, 2006 E F F I Z I E N Z E N T S C H E I D E T

26 Load management. Peak Clipping Valley Filling Load Shifting Strategic Conservation Quelle: wik-consult, ISI, ISE, 2007

27 Smart Grids. Shift in paradigm towards a transmission and distribution grid that meets new challenges such as decentralised production and energy efficiency Currently 6 (12) field trials in the context of the e-energy competition Quelle: European Technology Platform, 2006

28 EPRI vision of smart grids.

29 Smart grid a solution for large scale wind integration? Yes for local fluctuations Yes for fluctuations that are of the same magnitude as sheddable load. No for transregional issues. No for actual overproduction. The smart grid is no replacement for transmission and storage.

30 and here comes the Supergrid? Europe (onshore) Source: Desertec

31 and here comes the Supergrid? Europe (offshore) Source: European Coordinator for Connections to offshore wind power in Northern Europe

32 and here comes the Supergrid? - US Source: Secretary Chu, Speech at GRIDWEEK Conference, Sept , Washington D.C.

33 Summary Gemany has reached a high degree of wind power penetration and wants to increase that level further. However, it is reaching the limits of the transmission system in terms of regional distribution, temporal distribution and technology. Grid expansion and increased interconnection capacity can abate a number of these issues. Legal action is taken, but line construction meets intense public opposition. New technical solutions are necessary. Options discussed are: storage, load shifts, HVDC long distance transport, but none of them are fully thought through at the moment. Structural differences between US and Germany require different approaches.

34 Thank you for your attention. Dr. Christine Wörlen