111/11/2015 Reserved flow at the foot of large dams and green electricity Vincent Denis MHyLab Switzerland 1 st October 2009

211/11/2015 Agenda of the presentation  Small hydro in Switzerland – Production, Laws and directives  Impact of the reserved flow on the Swiss production  Turbining of reserved flows – technical constraints  Turbining of reserved flow – Three examples

311/11/2015 Small hydro according to the Swiss Law  Small hydropower plant : HPP with an output smaller than 10 MW  The output is calculated according to the art. 51 of the Federal Law on hydraulic forces (1916)  P = 10 x Q average x  Z

411/11/2015 Yearly Swiss electric power production in GWh (2007)

511/11/2015 Yearly Swiss Hydropower production

611/11/2015 Swiss hydropower production vs national consumption

711/11/2015 According to Swiss Federal Office for Energy Renewable electricity production (GWh/year) (Large hydro not included) Small hydro : % of the renewable electicity generation 9.27 % of hydro electricity generation 5.11 % of electricity generation

811/11/2015 Main Swiss Laws dealing with small hydro Federal Law on Hydraulic forces (1916) Federal Energy Law (1998) Federal Law on the electricity supply (2007) Federal Law on water protection (1991)

911/11/2015 Federal law on hydraulic forces Definition of « official output » (small hydro or not) Definition of the water rights and licences Security of operation and responsibilities

1011/11/2015 Federal Energy Law Objective : + 5’400 GWh of renewable energies by 2030 Objective : + 2’000 GWh of hydropower by 2030 (base : 2000) Access to the grid : Obligation to accept renewable energies in the grid, even if the production is not constant Small hydro is renewable up to 10 MW Renewables are supported by guaranteed feed-in tariffs (25 years for Hydro; decreasing tariff between ≈ 22 to 5 €cts/kwh)

1111/11/2015 Federal law on electricity market Definition of renewable energies (hydro, PV, geothermal energy, wind, biomass) Definition of the grid access conditions for the renewables Commercialization of the renewable electricity

1211/11/2015 Federal law on water protection Objectives : To preserve human, animals and plants health To guarantee the drinking and industrial water supply. To promote a rational use of water. To protect the natural and local biotopes To protect the fishes To protect the water streams as a part of the landscape To ensure irrigation To allow the use of the rivers and lakes for leisure To ensure a “natural” hydrology

1311/11/2015 Federal law on water protection – Main articles dealing with hydropower Art 31 : Reserved flows  Q 347 is considered as the calculation reference  Q 347 = natural discharge of a permanent water stream that is reached at least 347 days per year.

1411/11/2015 Federal law on water protection – Q 347 Q347 = 1’350 l/s

1511/11/2015 Federal law on water protection Art. 31 Minimal reserved flow : For Q 347 ≤ 60 l/s50l/s additionnal reserved flow per 10 l/s8l/s For Q 347 ≤ 160 l/s 130l/s additionnal reserved flow per 10 l/s 4.4l/s For Q 347 ≤ 500 l/s280l/s additionnal reserved flow per 100 l/s31l/s For Q 347 ≤ 2’500 l/s900l/s additionnal reserved flow per 100 l/s21.3l/s For Q 347 ≤ 10’000 l/s2500l/s additionnal reserved flow per 1’000 l/s150l/s For Q 347 ≤ 60’000 l/s10’000l/s

1611/11/2015 Federal law on water protection – Reserved flow Q347 = 1’350 l/s Q347 = 1’350 l/s => Qr = 280 l/s + (1350 l/s – 500 l/s)/100 x 31 l/s = 544 l/s

1711/11/2015 Federal law on water protection – Main articles dealing with Reserved flows Art 32 : Decrease of the reserved flow  If derivation ≤ 1000m, altitude ≥ 1750 m and Q 347 ≤ 50 l/s  If the river has no fishes and Q r ≥ 0.35 x Q 347  In case of emergency for drinking water supply, irrigation water supply or firemen use  Other special cases according to prior decision of the federal government

1811/11/2015 Federal law on water protection – Main articles dealing with Reserved flows Art 33 : Increase of the reserved flow  Weighting of interests !  Public interests, economic impact on the area, economic impact on the person asking for a license, energy supply.  Landscape aspect, biodiversity, water quality, drinking and irrigation water supply.

1911/11/2015 Impact of the reserved flow on the Swiss hydroelectric production More than 200 dams in Switzerland

2011/11/2015 Impact of the reserved flow in terms of hydropower production Hydropower production forecast according to the Swiss utilities association (AES)

2111/11/2015 Impact of the reserved flow in terms of hydropower production  The increase of the reserved flow (according to the 1991 Law) will lead to a total production losses of 2’500 GWh.  In other words, the increase of small hydro production will only allow to compensate these losses.  Considering the average European CO2 emission level of 480 t/GWh, these losses will « generate » 1’200’000 t/year.  I do not want to say that every drop of water should be used

2211/11/2015 Impact of the reserved flow in terms of hydropower production  Of course, this comparison is a little bit provocative  The goal is not to say that every drop of water should be used in order to generate electricity without taking into account the environment  However, we should keep in mind the fact that the water protection can lead to an air pollution.  It is essential to find a good compromise !

2311/11/2015 How to mitigate the production losses ?  The dam generally present a low to medium head between its foot and the water level of the reservoir.  This head represent an energy that is lost if the reserved flow is “simply” rejected at the foot.  Why not turbining this water and consequently reduce the production losses ?

2411/11/2015 What are the constraint of a reserved flow turbining project ?  Generally, the head is not constant (function of the remaining water in the reservoir) => It could be necessary to operate the turbine at variable speed.  The reserved flow shall be kept constant as it is a legal value that is a part of the license => The turbine shall be regulated

2511/11/ Swiss examples of ongoing large hydropower plants reserved flow turbining projects

2611/11/2015 Montsalvens dam, Montsalvens dam, Broc Hydro power plant – Fribourg - CH – Groupe E Gross Head = 122 m Electric power = 30 MW New requested Q r = 500 l/s

2711/11/2015 Montsalvens dam Water level variation Max water level : 801 m Min water level : 775 m Downstream level : 759 m => Head : 16 to 42 m

2811/11/2015 Montsalvens dam Head duration curve Average yearly head duration curve

2911/11/2015 Montsalvens dam Turbine rotational speed and efficiency Turbine speed variation between 888 and 1441 rpm in function of the head variation.

3011/11/2015 Montsalvens dam Turbine rotational speed and efficiency Turbine efficiency variation between 84.8% and 88.5 % in function of the head variation.

3111/11/2015 Montsalvens dam Reserved flow turbining Design flow: 500 l/s Variable head: m Electrical output: 160 kW Production: 1'250'000 kWh/year Consumption of 300 households

3211/11/2015 Montsalvens: production losses  Gross head: 122 m  Reserved flow: 500 l/s  Corresponding production: ~ 3’200’000 kWh/year  SHP recovered production: 1'250'000 kWh/year  Production loss: ~ 1’950’000 kWh/year (61%) Consumption of 500 households  CO 2 increase on the European interconnected grid: tonnes /year

3311/11/2015 Rossinière dam, Rossinière dam, Montbovon hydropower plant - 30 MW (Fribourg - CH) – Groupe E Gross Head = 89 m Electric power = 30 MW New requested Q r = 400 l/s

3411/11/2015 Rossinière dam Reserved flow turbining  Design flow: 400 l/s  Variable head: m  Electrical output: 50 kW  Production: 390'000 kWh/year  Consumption of 100 households

3511/11/2015 Rossinière: production losses  Gross head: 89 m  Reserved flow: 400 l/s  Corresponding production: ~ 1’800’000 kWh/year  SHP recovered production: 390'000 kWh/year  Production losses: ~ 1’410’000 kWh/year (78%) Consumption of 350 households  CO 2 increase on the European interconnected grid: tonnes /year

3611/11/2015 Le Day dam, Le Day dam, Romande Energie SA, CH Les Clées (VD) power plant - 27 MW – Montcherand (VD) power plant – 14 MW -

3711/11/2015 Reserved flow turbining Le Day dam  Reserved flow: 300 l/s l/s  Variable head: m  Electrical output: 100 kW  Production: 560'000 kWh/year  Consumption of 140 households

3811/11/2015 Le Day dam: production losses  Gross head: 176 m for les Clées, 104 m for Montcherand  Average reserved flow: 400 l/s  Corresponding production: ~ 5’790’000 kWh/year  SHP recovered production: 560'000 kWh/year  Production loss: ~ 5’230’000 kWh/year (90%) Consumption of 1050 households  CO 2 increase on the European connected grid: + 2’510 tonnes /year

3911/11/2015 Reserved flow turbining  This possibility tends to an optimal use of resources as :  It mitigates the effects of an increase of the reserved flow on the electricity production and on CO 2 emissions.  It uses an existing infrastructure  It allows a strict respect and an easy check of the reserved flow  It has strictly no negative impact on the environment.

4011/11/2015 Conclusion RESERVED FLOW TURBINING SHOULD BE ENCOURAGED AND PROMOTED BY THE AUTHORITIES AND THE ENVIRONMENTALISTS !