The accompanying materials were prepared by EDP and are not to be distributed or reused in any manner without prior consent.

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2 Terms of use The information's contained in this communication is confidential, may be privileged and is intended for the exclusive use of EDP in this conference. The accompanying materials were prepared by EDP and are not to be distributed or reused in any manner without prior consent. Some information supplied by EDP may be obtained from sources that are considered reliable, but are no way warranted by EDP as to accuracy or completeness. Absent a specific agreement to the contrary, EDP has no obligation to update any content or information provided in this document.

3 Flexibility Frades II / Venda Nova III Variable speed, its performance during the 1st year of operation and its contibution for the Portuguese Energy System

4 Outline Why a second repowering? Why variable speed? Variable Speed - Overview of Electric Machinery Options Frades II, Main Data Design Commissioning The MIBEL Market Ancillary Services in Portugal Main problems Conclusions 4

5 Why a second repowering? Frades II North-Western Portugal 2nd repowering at site, after Vila Nova (1951) and Frades (2006) 4 times Frades, similar layout 420 m, 200 m 3 /s!!! 840 MVA!!! Milestones contract signed end of trial run January 2017 commercial op. March

6 Why a second repowering? Frades II Increase the pumping capacity to contribute for the growth of intermittent renewable power capacity, specially with wind origin Liberalization of the Iberian electricity market; Government objective to increase \ renewables; Reduce country s dependence on fossil fuel Eólica: Potência instala acumulada em Portugal Fonte: Parques Eólicos em Portugal, INEGI, APREN,

7 Why variable speed? Relevant technical aspects: Advantages In turbine mode, increase of the head range and better efficiency, especially at part loads. In pump mode, the possibility to control the input power Potential to contribute to the stability of the grid by injecting active and reactive power, very quickly. 7

8 Why variable speed? Relevant technical aspects: Advantages An increase of efficiency, in turbine mode, especially at part loads, derived from the operation at subsynchronous speeds. operation area at synchronous speed operation area at subsynchronous speed Flow Flow h= const h= const Head Head 8

9 Why variable speed? Relevant technical aspects: Advantages An useful input power band variation in Pump mode for all heads. variable speed operation area Input Power Fixed speed operating curve Head 9

10 Variable Speed Overview of Electric Machinery Options Rotor of Synchronous Generator Rotor of Double Fed Induction Generator Courtesy of: 10

11 Variable Speed Overview of Electric Machinery Options High VoltageGrid Double Fed Induction Generator DFIG FixSpeed VarSpeed BlockTransformer AC-Excitation System = DC-Link = Synchronous Machine with Salient Poles (SYM) as Generators & Motor- Generators Double Fed Induction Generator Stator Fed Synchronous Generator AC-Excitation Transformer ~ Grid-Side ConverterUnit ~ Rotor-Side ConverterUnit DFIG Pump- Turbine Converter Fed Synchronous Machine CFSG *<100 MVA High VoltageGrid (2 Speed -> Pole Switching Synchronous Generator) BlockTransformer Full Power Converter = DC-Link = DC-Excitation ~ ~ Pump- Turbine Grid-SideConverter Unit Stator-SideConverter Unit Synchronous M-G Courtesy of: 11

12 Frades II, Main Data Excitation Aumentar esta seta 4x9,5 MVA=38 MVA The VSI is an integral part of the asynchronous machine and is directly connected to the rotor. It intervenes in all modes of operation, namely in the electrical start-up of the machine, in the speed control, in the excitation and also, as required by TSO, in the stabilization in situations of serious network failure (voltage short circuits in the network). 12

13 Frades II, Main Data Generator Max. Stator Power 433 MVA Rated Stator Voltage 21 kv + 5% Nominal Stator Current A Rated Stator Frequency 50 Hz Rated Rotor Voltage V Max. Rotor Current A Rotor Frequency ~ 0 3 Hz Speed Range rpm Restricted Operation rpm Runaway Speed 520 rpm Start-up in Turbine 60 seconds Start-up in Pump 200 seconds Ramp rate in turbine mode 8 MW/s Ramp rate in pumping mode 7 MW/s Weight ~ 300 t (laminations) Outer Diameter mm Circumferential Speed (rated) 106 m/s Circumferential Speed (max.) 146 m/s (526 km/h) Max. centrifugal acceleration 7970 m/s 2 (~ 810 x g) 13

14 Frades II, Main Data Powerhouse Power cable tunnel Surge chamber Tailrace tunnel Access tunnel Pensotck branch 60 m 14

15 Design Slipring Assembly, Brushes 6 sliprings (2 per phase) + 1 neutral 7100 A (AC), 4.0kV Up to 288 brushes All sliprings with helicoidally grooves Open circuit ventilation concept Self ventilated sliprings System for carbon dust extraction Manifold Air intake Courtesy of: 15

16 Commissioning Total Harmonic Distortion (THD) in auxiliary Systems During the dry and hot commissioning of the VSI with the power unit 1, there were strong and unexpected harmonic distortion. Obviously the same is caused by the VSI and feed to the medium voltage system. Problem: wide range of strong higher harmonics in the range above the 13 th harmonic and above 2,5kHz Solution: a combination of an active filter for the range up to 2,5kHz and a passive high-pass filter for the range above 2,5kHz, on Low Voltage system 16

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18 The major investments made in recent years have increased significantly the Iberian reserve margin Installed capacity in Iberia (GW) Hydro Nuclear Special Regime strong growth CCGT CCGTs strong growth Fuel/Diesel Oil Coal Special Regime Remaining technologies stable Growth Demand 28% Capacity 97% Special Regime 321%

19 Market Prices drivers RESERVOIR STORAGE DAILY WIND GENERATION 19

20 Daily Market Prices OMIE (Spain) Average daily prices (Spain)

21 Energy and Ancillary Services (Secondary & Tertiary reserves) 21

22 Wind Generation Forecast for Portugal and Spain 12 days Spain Portugal 22

23 Particularly In Portugal Hydro and Wind complement each other Wind Hydro During the Peak hours hydroelectricity is produced using generation mode of the reversible units During the Off-Peak hours the surplus of energy is stored by using pumping mode of the reversible units 23

24 In Portugal Wind variability is very big Wind volatility and unpredictability assumes a major role in the Portuguese electricity system Monthly Wind Generation and about MW or more can be lost within a few hours 24

25 Reversible Units in a Market environment Example Pedrógão Salamonde Rio Seco 1 2 Upper Reservoir Example Alqueva Frades Tanes Prices /MWh Lower Reservoir 2 To allow the economical Pump-Turbine cycle, the price ratio (Off-peak/Peak) should be lower than the operation efficiency (~80%) H1 H3 H5 H7 H9 H11 H13 H15 H17 H19 H21 H23 Off peak Price < 0.8 x Peak price Example Price (peak): 50 /MWh Price (off-peak): 50 x 0.8 < 40 /MWh IMPORTANT : Besides the price difference it is also necessary to have enough energy in the market at this prices to allow the pumping operations... 25

26 Why variable speed? What is the advantage of the variable speed: 2 Fixed speed units 2 variable speed units 2 x Unit s Pump Power Power 2 x VarSpeed Power range Power Surplus Unit s Pump Power VarSpeed Power range Time 26

27 Hydro Pumping plays an important role in the Portuguese Ancillary Services Market Hydro Pumping share by different markets Pumping occurs in the daily market, whenever the price spreads are interesting, but intra-day and Ancillary Markets also create opportunities for pumping. Historically a significant hydro pumping share is mobilized through tertiary reserve Portuguese Secondary and Tertiary Reserve Energy Historical Pumping Tertiary Pattern Thermal power plants have been decreasing its share in ancillary services markets and Hydro has been increasing. 40% to 50% of the total hydro tertiary reserve was mobilized in pumping mode, denoting the importance of pumping in the system management. Significant pumping is carried out through tertiary reserve mobilized by System Operator and occurred during the off-peak hours. 27

28 Commissioning phase 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Availability 2016/2017 JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN Unit 3 Unit 4 28

29 Commissioning phase 29

30 Conclusion - I An important contribution For the EDP Production portfolio: Increase of pumping capacity (+ 780 MW) Able to inject 2x420 MVA in the grid in about 2 min For the Portuguese electric system For Portugal For the environment Quicker response in fault grid scenarios, providing more stability to the grid Possibility of AGC in generator and pumping mode Capacity to perform ancillary services in pump mode (the first in Iberia) Reduction of the country s energetic dependence on fossil fuel Reduction of emissions of greenhouse gases less kt CO 2 /year 30

31 Conclusion - II Commissioning was made on a dry year, so much less inflows compared with a normal situation, so less revenues On this period EDP the net operations on the day-ahead market were on the buying side (for the pumping mode) On the Intraday Market EDP has a net selling position, since after the day-ahead markets it is possible to establish the selling price according to the pumping cost The ancillary services revenues were strongly reduced by the government compared with the initial estimations The imbalances on this Power Plant are not easy to compensate within the balancing area, so it is an extra cost on the operations due to the Portuguese market rules

32 Nevertheless, the main message should be

33 Energy Management Contacts Berto Martins, Head of Dispatch & Planning EDP S.A. (UNGE) Phone: Power Systems and Automation Contacts Visit EDP Website Mário J. Oliveira Silva, Senior Manager EDP Gestão da Produção de Energia, S.A. Phone: Site: Special thanks to:

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