Pump Storage Technology

Energy

Pump Storage Technology

The Situation in Germany

www.german-renewable-energy.com

Dr. Albert Ruprecht

Institute of Fluid Mechanics and Hydraulic Machinery University of Stuttgart, Germany

Contents



_{Pump storage power plants}

Storage demand in Germany



_{Status quo in Germany}



Comparison to alternative storage technologies



_{Technical concepts}

New PSP projects



_{The planed power plant Atdorf}

Conclusions

Typical Pump Storage Scheme Q H g P Power:

Typical Pump Storage Scheme

Typical Pump Storage Scheme

Requirement of regulative power from PSP

Consumption

Production

Electrical grid

Increasing fluctuating production from renewable energy sources (e. g. wind, PV)

Renewable production in the 50hertz grid (north east Germany) Re new able pr oduc tion in MW Year 2010

Short term fluctuations Long term fluctuations

January 2009 Wind pow er in MW Production Prognosis

January 2009 Progno sis er ro r in MW

Renewable production in the 50hertz grid (north east Germany) Year 2010 Di fference to the av erage produc ti on i n % Low production

Accumulated difference to averaged production

Year 2010

Needed Storage volume: 7% of the yearly electricity production

Ac c umul ated Di fference to the av erage produc ti on i n % D: ~600 TWh => 40 TWh

Development of wind energy and PV in Germany 0 5.000 10.000 15.000 20.000 25.000 30.000 35.000 40.000 2008 2010 2012 2014 2016 2018 2020 2022 2024 2026 2028 2030 L e is tu n g [ M W ] 0 20 40 60 80 100 120 140 160 S tr o m e r z e u g u n g [ T W h ] Leistung Onshore Leistung Offshore Stromerzeugung gesamt Wind PV

Required regulating power

Strong increase of positive and negative regulating power Increase by a factor of 2 until 2020

Power plants with very flexible operation

Requirements

Fast short term regulating power negative regulating power positive regulating power Long term storage

Quelle: Schluchseewerk AG T urb in e mod e Pu mp mod e Number of starts Duration of operation

Zunahme von Betriebsartenwechseln

Number of operation mode changes

%

Jahr

Increase of load to the turbines structures => Monitoring, Condition based monitoring

Installed PSP in Germany Inst all ed pow er in MW No o f P owe r Pl ants

Installed PSP

Alternative storage technologies

Pump storage is the only available technology with large power and large capacity

Source: Vennemann, RWE

Source: Vennemann, RWE

Losses in a pump storage power plant 100 99,5 99 _97,5 88,5 88 88 87,5 82,5 81 80,5 80 80 0 0,5 0,5 _1,5 0,5 0 0,5 1,5 _{0,5 0,5 0} 5 9 0 10 20 30 40 50 60 70 80 90 100 Ene rgie ein spe isu ng Tra nsfo rma tor Eig enve rbra uch Mot or Pum pe Roh rlei tung Sp eic her Roh rlei tung Turb ine Gen era tor Eig enve rbra uch Tra nsfo rma tor Ene rgie abg abe En e r g ie [% ] Verluste Energie

Technologies

• Separate turbines and pumps • Pump turbines (fixed speed) • Pump turbines (variable speed)

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

Hydraulic short circuit

Simultaneous operation of pump and turbine

Example: required negative power 100 MW Pump power: 150 MW

Turbine power: 50 MW

Operation range

Re

gelbereich

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: 300 – 346,4 U/min, => 100 MW regulating power in pump mode) Example PSP Goldisthal

0 100%

-100% _{max. pump power}

max. turbine power

By combining the four units

nearly the whole operation range can be used as regulating power

(except very small gaps)

-60%

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

Verhalten im Leistungsregelbetrieb

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.

Power quality

Power

Quelle: Schluchseewerk AG

Power: 1 400 MW Head: 600 m

Reservoir: 10 mio m3

Source: Schluchseewerk AG

The project Atdorf Animation of

head water basin

The project Atdorf Animation of tail

water basin

No of units 6

Operation range, turbine mode 60 to 1400 MW

Operation range, pump mode 160 bis 1400 MW

Discharge (Pump / Turbine) 200 / 270 m³/s

Motor/generator (asynchronous) 280 MVA per unit

Total storage efficiency ca. 80 %

Modes of operation pump, turbine, phase shifting

 Machine caverne:

length 220 m, width 27 m; height 52

 Trafo caverne: length 160 m lang

 Tail racee tunnel: length 8,6 km

 2 penstocks: length 730 m each, vertical

 Access tunnel: length 3,2 km

 Power cable tunnel: length 1,4 km

Source: Schluchseewerk AG

The project Atdorf Surge tank Source: Schluchseewerk AG Caverns Access tunnel Tail water

Caverne

The project Atdorf

Conclusions

• There is a strongly increasing demand on storage and on regulating power.

• Pump storage power plants are the only available large scale technology which is most cost effective.

• In Germany has an installed PSP with 6.4 GW power and 38 GWh capacity.

• There are projects for another 4.4 GW power and 40 GWh capacity.