Pump Storage Requirements and Comparison with other Technologies

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1 Pump Storage Requirements and Comparison with other Technologies Albert Ruprecht Institute of Fluid Mechanics and Hydraulic Machinery University of Stuttgart 1

2 Content Introduction Demand on pump storage capacity Status Quo of pump storage in Germany Comparison with other storage technologies Potential for pump storage in Germany Requirements to pump storage schemes Conclusions 2

3 L eistu ng [M W ] Introduction Strong increase of volatile renewable energies in Germany Compensation for volatility by storage schemes Leistung Onshore Leistung Offshore Stromerzeugung gesamt Electricity production from wind and photovoltaic Wind energy S trom erzeugung [TW h] PV

4 Introduction Expected electricity generation by wind and photovoltaic Electricity demand in Germany app. 600 TWh 4

5 Demand on storage capacity 4 control regions 50 Hz Transmission 5

6 IHS - Institut für Strömungsmechanik und Demand on storage capacity 6

7 Demand on storage capacity Required storage capacity: 7 10 % of the entire electricity consumption Total consumption in Germany: ~ 600 TWh Required storage: TWh (without exchange, without load management etc.) Real demand on long term storage: TWh 7

8 Demand on storage capacity Einspeisung bzw. Prognose [MW] very fast drop of feed in 8000MW in a few hours large dicrepancy between prognosis and production Juni 2012 Einspeisung Wind & Solar Prognose Wind & Solar 8

9 Demand on storage capacity Long term storage TWh With consideration of exchange, load management etc. (similar value as in BMU Leitstudie 2010 ) Short term Storage High demand on short term regulating power (positive as well as negative) Triplication until 2020, Dena 9

10 Pump storage in Germany At present 31 power plants Power: 6,4 GW Energy: 37,4 GWh 10

11 Pump storage in Germany At present 31 power plants Power: 6,4 GW Energy: 37,4 GWh Additional 2 GW under contract in Austria and Luxemburg Demand 500 times larger aus ZfES (2012): Stromspeicherpotenziale für Deutschland ; Studie im Auftrag des Zentrums für Energieforschung Stuttgart (ZfES) e. V. 11

12 Pump storage power plants in Germany Large pump storage power plants in Germany many power plants are more than 40 years old 12

13 Large pump storage power plants in Austria many power plants are more than 40 years old 13

14 Other storage technologies Compressed air storage (diabatic or adiabatic) Mobile batteries (E-mobility) Hydrogen storage Methan storage (Power-to-Gas) aus ZfES (2012): Stromspeicherpotenziale für Deutschland ; Studie im Auftrag des Zentrums für Energieforschung Stuttgart (ZfES) e. V. 14

15 Other storage technologies Source: Vennemann, RWE Pump storage is the only available technology with large power and large capacity 15

16 Efficiency [%] Speed of Power Shift [%/min] Electrical efficieny (power to power) and power reaction time diabatic adiabatic Electrical Efficiency Power Shift Pumped Storage Compressed Air Mobile Batteries Hydrogen Storage Power to Gas Source: ZfES (2012): Stromspeicherpotenziale für Deutschland ; Studie im Auftrag des Zentrums für Energieforschung Stuttgart (ZfES) e. V. 16

17 IHS - Institut für Strömungsmechanik und Storage costs Storage costs in cent/kwh out short-term storage long-term storage * Short-term storage: 9-29 cent/kwh, PSP: 9 cent/kwh Long-term storage: cent/kwh, PSP: cent/kwh Source: ZfES (2012): Stromspeicherpotenziale für Deutschland ; Studie im Auftrag des Zentrums für Energieforschung Stuttgart (ZfES) e. V. 17 Power to Gas Pumped Storage Compressed Air Mobile Batteries Hydroden Storage Power to Gas Pumped Storage Compressed Air Mobile Batteries Hydroden Storage Specific Storage Costs [ cent/kwh] out of range ( cent/kwh)

18 IHS - Institut für Strömungsmechanik und Specific investment costs Source: ZfES (2012): Stromspeicherpotenziale für Deutschland ; Studie im Auftrag des Zentrums für Energieforschung Stuttgart (ZfES) e. V. 18

19 Demand on storage capacity Additional advantages of pump storage power plants power frequency control voltage control reactive power compensation providing reserve power in case of disruption and providing black-start capability 19

20 Potential for pump storage in Germany Typical Pump Storage Scheme Power: P g H Q 20

21 Potential for pump storage in Germany Public discussion: no potential FALSE! Required: appropriate head difference and discharge Upper reservoir Lower reservoir At present 12 larger projects are in planning (economical situation has to be improved!) Power: 4,4 GW (+ 69% compared to Status Quo) Storage capacity: 40,6 GWh (+103% compared to Status Quo) Several local potential studies are available 21

22 Potential for pump storage in Germany New projects under discussion 22

23 Potential for pump storage in Germany Potential study for BW 29% of the area would be suitable 201 Suitable locations in areas with low conflict potential Performance: 116 GW Storage capacity:1 TWh (25 times the existing capacity) Achatz, R., Potenziale der Pumpspeicherung in Baden-Württemberg, EnBW-Symposium Potenziale der Wasserkraft in Baden-Württemberg, Stuttgart, Juli => Similar potential in the other federal states (with low mountain ranges) => Min. 4-5 TWh (20% 25% of the demand) can be realised in Germany. 23

24 Requirements to pump storage schemes Pump storage schemes must be very flexible to provide fast and flexible positive and negative control power Because of the reuired flexibility many start an stop cycles and many rapid load changes are necessary. Exspecially older power plants are not always design for this flexible operation. => life time assesment Technologies Separate turbines and pumps Pump turbines (fixed speed) Pump turbines (variable speed) 24

25 Requirements to pump storage schemes Example PSP Kops II Example Kops II: New power plant between existing reservoirs Fully flexible operation, hydraulic short circuit Pelton turbine below tailwater 3-stage storage pump 25

26 Requirements to pump storage schemes Hydraulic short circuit Simultaneous operation of pump and turbine Example: required negative power 100 MW Pump power: 150 MW Turbine power: 50 MW Bild: VIW 26

27 IHS - Institut für Strömungsmechanik und Requirements to pump storage schemes Operation range Regelbereich Full operation range from max. turbine power to max pump power 27

28 Requirements to pump storage schemes Example PSP Goldisthal Drehzahlvariable Maschinen 4 Pump turbines with 265 MW each 2 Synchronous motor/generators (fixed speed) 2 double-feed asynchronous motor/generators (variable speed) (speed range: ,4 U/min, => 100 MW regulating power in pump mode) 28

29 Requirements to pump storage schemes 100% 0-60% Operation range of one unit max. turbine power -100% max. pump power By combining the four units nearly the whole operation range can be used as regulating power (except very small gaps) Positive effects of variable speed pump turbines: - Power control in pump mode - Higher power control quality in turbine mode - Higher efficiency at high head variations 29

30 Power Power quality Assumed requirement: linear Increase of power demand Turbine governor opens to turbine By inertia of the water passage the power increase at synchronous machines increases very slow. The asynchronous machines follow the demand accurately, the bridge the gap by their inertia. Speed 30

31 Conclusions Large demand on long and short term storage Required capacity: ~ 20 TWh Pump storage ist the best technology (efficiency, rapidness, availability...) Large potential is available in Germany Economical feasible framework is required. Pump storage will not meet the entire storage demand, The development of other technologies (CAES, Power-to-Gas) is also necessary Use of pump storage in other countries (Norway, Sweden, Swiss und Austria) ch 31

32 Thank you for your attention 32