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EDF Hydro Engineering Center
(CIH)
Innovation and Research serving an industrial
Hydraulic Safety Project:
upgrading spillway systems at EDF dams
(MRCD project)
IJREWHS, Spa (Belgium) August 29, 2014
Dr. Denis AELBRECHT EDF-CIH

Short Title following Stefanos recommendation:
Innovation makes EDF dams spillways
safer

Contents
1. A few words about EDF
2. Flood risk : #1 safety industrial issue for EDF Hydro
3. Solutions with PKW technology: basic concept, design and development
4. PKW realizations at EDF dams
5. Solutions without PKW technology: increase of MWL, structural reinforcements
6. Take home message
D. Aelbrecht (EDF) - IJREWHS, Spa - Aug. 29, 2014 3

1. A few words about EDF

EDF = European leader in the power industry Generation + Transmission + Delivery + Trading/Services Generation assets :
Total installed power capacity installed Worldwide : 128 GW Total installed power capacity installed in France : 100 GW
65 GW Nuclear 20 GW Hydro 15 GW Thermal (fossil-fired plants)
38 millions customers worldwide ; 28 millions in France Total annual generation is about 630 TWh First European production through Renewables sources Weakest European CO2/MWh average emission rate 156 000 employees worldwide

Installed capacity 20 GW
Average generation 44,5 TWh
Run of the river
3,9 GW
Reservoir 8,6 GW
Run of the river 18,2 TWh
Reservoir 16,1 TWh
Pondage 3,1 GW
Pump storage 4,4 GW
Pondage 9,1 TWh
Pump storage
1,1 TWh
20% of the overall EDF generation capacity
10% of the average EDF output
EDF Hydro features

FRANCE EDF 20 600 MW
BELGIUM SPE 200 MW
SWITZERLAND Alpiq 3 000 MW
ITALY Edison / Edipower 1 500 MW
LAOS Nam Theun 2 1 100 MW
Including CERGA ( Gambsheim) & RKI ( Iffezheim) owned 50/50 with ENBW
Hydropower in the EDF Group

DPIH 5 600 people 5 Operation & Maintenance Units
4 000 people UP Alpes UP Centre UP Est UP Mditerrane UP Sud-Ouest
2 Engineering Units
1 600 people CIH : Centre dingnierie Hydraulique DTG : Division Technique Gnrale
4600 MW
2700 MW
7600 MW
2500 MW
2600 MW
In addition EDF-SEI operates 14 hydropower plants in Corsica and overseas departments
Overall organization of EDF Hydro

EDF Hydro fleet
640 dams and 436 hydropower plants From 100 kW up to 1800 MW
- all types of HPP ( run of the river, pondage, reservoir ) - All types of dams ( arch, gravity, concrete, earthfill..) - Including 5 GW pumped storage plants - Includind one 240 MW tidal power plant
Fully automated or remote controlled
The 100 largest facilities are operated from 4 remote control centers, allowing 14 GW on the grid in less than 20 mn
Most of the power plants are run under a concession licensing agreement regime

EDF Hydro : Challenges and Drivers
Maintenance and life duration extension
Increase safety against flood and seismic risks
Develop new Hydro assets, in France and Worldwide
Hydro relicensing in competition: propose the best offers (generation-environment-safety)
Water resource sharing with other usages (irrigation, water supply, )
Security of staff on our works sites

2. Flood risk: #1 safety industrial issue for EDF Hydro

Flood risk : a major safety issue for EDF Hydro
Flood = 1st cause of operating dam failures On a basis of 17,000 high dams (H > 15 m - China excluded - source : ICOLD 1995)
Circumstances Dam failures
Fatalities
Floods 90 9 000 Upstream failures 6 1 000 Earthquakes 3 - - Wars 6 1 300 First filling 50 5 500 Ageing 40 600 TOTAL 200 17 000
Witka-Nidow dam failure (Poland) Aug. 2010

EDF Flood risk management approach
Flood risk control pillars
Design of spillway capacity = passive barrier => Need to check or upgrade
spillway capacity
Managing dams during floods = active barrier => Need to prepare operators
(SIMBA simulator)

Risk-based approach to prioritize actions :
Risk = Proba MWL Dam vulnerability Consequence of dam failure - Proba MWL : probability of MWL exceedance => NP index, from 1 to 5
- Dam vulnerability : sensitivity to MWL exceedance => V index, from 1 to 4
- Consequences : No regulatory-based considerations (so far). Used by EDF to define provisonal mesaures to reduce risk and to prioritize future works
Risk mapping :
Check spillway capacity: need to upgrade ?

Spillway upgrade solutions must be complete Spillway capacity increase + Flow routing + Dissipation + Erosion risk + Dam stability
Spillway upgrade solutions must be robust Safe passage of debris Gates reliability Sensitivity to potential increase of Inflow Design Flood (IDF) conditions
Spillway design upgrade methodology

Spillway upgrade solutions catalogue : 2 main solutions families
Increase MWL
or Iso-MWL => increase spillway capacity
Spillway design upgrade methodology

Gated systems
Non-gated systems
Spillway upgrade : gated or non-gated systems ?
+ - Flexibility Maximize volume for generation
Cost of construction Cost of maintenance Potentially poor reliability High specific discharge (Q/L) Head flows : saturation of rating curve (Q ~
H ) May require power and/or human presence
+ - Autonomy Reliability Cost of construction and
maintenance
Q increases slowly with H from weir crest Requires long lengths Limited space to add new free surface flow
spillway
Innovation : Piano-Key Weir (PKW)

3. Piano Key - Weir (PKW) technology: basic concept, design and R&D

Ce que vous devez retenir (suite)
illustration 1 : How to draw only 4 straights connected segments, joining these 9 points ?
Innovation : Think out of the box

?
illustration 2 : in a 2 stairs TGV, how to make passengers move from one coach to another one downstairs ??
Innovation : Think out of the box
Just do it upstairs !!

B
Bo
Bi
Wo
Wi
Ts W
Bb P
Q Cd . L . (2g)1/2 . (H)3/2
Application for free surface spillway
Dont think straight, think labyrinth, and increase effective length L
PK-weir (2000 )
An old idea: Labyrinth
Bakhada dam (1938)

PKW basics : main features
Main advantages : Developed length => increasing Q while limiting H increase Can be installed in limited available space on top of dam Allows limiting decrease of Normal Water Level (NWL)
Avoids loss of storage / power output capacity
Allows limiting increase of Maximum Water Level (MWL) Positive for Dam Stability Structural issue Typical head of a PKW is ~ 1 1,5 m for rehabilitation of existing dams
Cost of construction
B
Bo
Bi
Wo
Wi
Ts W
Bb P

Main geometrical parameters :
Ratio L/W Height P Ratio key width Wi / Wo Sidewall thickness Ts
B
Bo
Bi
Wo
Wi
Ts W
Bb P
Increase developed length at small head 6-7 (B ~ 12 m upstream / downstream)
Better incoming flow feeding in inlet keys > 5 m
Inlet to be large enough for flow feeding in inlet keys and flow saturation in outlet keys > 1,3
Structural design data => can affect up to 20% between steel / concrete 35 50 cm
L W
PKW basics : Hydraulic design

PKW-Type A: the reference baseline
Lemprire F., Ouamane A. (2003). The piano keys weir: a new cost-effective solution for spillways. Hydropower & Dams 10 (5), 144-149.

PKW-Types
Type A
Type B
No downstream overhang
Type D
Type C
No upstream overhang
= Type B inverted
D. Aelbrecht (EDF) - IJREWHS, Spa - Aug.

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