SMALL HYDRO BIG CHALLENGES Renewable Energy World Asia 2016 Martin P. Bieri. September 21, 2016

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1 SMALL HYDRO BIG CHALLENGES Renewable Energy World Asia 2016 Martin P. Bieri September 21, 2016

2 CONTENT Introduction Potential in Southeast Asia Challenges in Small Hydro Main Design Steps (Bad) Examples What can go wrong, will go wrong! (Selected) Design Basic Studies Hydraulic Design Small Dams and Weirs E&M Equipment Conclusion Lessons Learnt

INTRODUCTION Small Hydropower Potential in Southeast Asia In Southeast Asia some large hydropower projects currently under development, but also high potential for small hydro: Target of 15% of

3 INTRODUCTION Small Hydropower Potential in Southeast Asia In Southeast Asia some large hydropower projects currently under development, but also high potential for small hydro: Target of 15% of renewable energy in the total power supply by 2020 Renewable generating mix relies almost exclusively on hydro (12%) Installed small hydropower capacity: Vietnam: 622 MW (<30 MW) Philippines: 248 MW Thailand: 146 MW (<10 MW) Small hydropower potential: Vietnam: 2,205 MW (about 175 projects) Philippines: 1,876 MW Indonesia: 1,267 MW (about 125 projects) Asia 65% Global distribution of small hydropower resources (<10 MW) [UNIDO and ICSHP 2013] "SMALL HYDRO - BIG CHALLENGES" 3

Low budget for design (3 to 5% investment) of complex infrastructure Local not experienced designers Lack of robust

4 INTRODUCTION Small Hydro Big Challenges What is Small Hydro? No consensus on definition Generally installed capacity <30 MW Where are the Big Challenges? Low budget for design (3 to 5% investment) of complex infrastructure Local not experienced designers Lack of robust standardized designs, costing procedures, specifications, and contract documents Unsustainable plants due to inappropriate design (Low efficiencies, power loss, shortages, high O&M cost, short lifetime) "SMALL HYDRO - BIG CHALLENGES" 4

poor performance Installed Capacity Example: Investment Design Fee (5%) Low 200 MW USD 400

5 INTRODUCTION Large Hydro versus Small Hydro Large Hydro Small Hydro Budget for design High Low Designer experienced (international) unexperienced (local) Risk of errors resulting in poor performance Installed Capacity Example: Investment Design Fee (5%) Low 200 MW USD 400 million USD 20 million High 20 MW USD 40 million USD 2 million "SMALL HYDRO - BIG CHALLENGES" 5

6 INTRODUCTION Main Design Steps Objective: Satisfactory functional structure at a minimum total cost. Topography and geology of the site Evaluation of water resource (potential) Site selection and layout (alternative study) Hydraulic and structural design E&M equipment including control-command Environmental impact assessment and mitigation measures Economic evaluation of the project and financing potential Institutional framework and administrative procedures to attain necessary consents [ESHA 2004] "SMALL HYDRO - BIG CHALLENGES" 6

Typhoon Nona in December 2015 Lessons learnt: Check Flood levels

7 EXAMPLE FLOOD SAFETY Inappropriate Flood and Sediment Study before 1.2 MW HPP, Philippines: Complete destruction of powerhouse during Typhoon Nona in December 2015 Lessons learnt: Check Flood levels Powerhouse foundation on rock after "SMALL HYDRO - BIG CHALLENGES" 7

8 EXAMPLE SEDIMENTS Inappropriate Flood and Sediment Study before 1.2 MW HPP, Philippines: Complete destruction of powerhouse during Typhoon Nona in December 2015 Lessons learnt: Check Flood levels Powerhouse foundation on rock Sediment assessment after "SMALL HYDRO - BIG CHALLENGES" 8

EXAMPLE PLANT PERFORMANCE Inappropriate Hydraulic Design 10 MW HPP, Indonesia: Rather high head losses of approx. 10 m for gross head of about 160 m and power waterway of approx. 2.

9 EXAMPLE PLANT PERFORMANCE Inappropriate Hydraulic Design 10 MW HPP, Indonesia: Rather high head losses of approx. 10 m for gross head of about 160 m and power waterway of approx. 2.5 km length (mean velocities of 2.5 m/s): Sedimentation Air entrainment in the waterways Head losses due to too high installation of Francis units (loss of about 10 m head) "SMALL HYDRO - BIG CHALLENGES" 9

10 EXAMPLE DESIGN Inappropriate Geotechnical and Hydraulic Design Cut-slopes 8.8 MW HPP, Indonesia: High intensity rainfalls expected in the project area Initial design with very steep cut-slopes, large excavation and insufficient drainage, leading to potential slope instabilities Inappropriate design of desander High O&M costs in case of slope failures and forced outages due to sediment entrainment in the headrace system Desander "SMALL HYDRO - BIG CHALLENGES" 10

sediment entrainment (missing coarse racks or baffles) Due to severe abrasion damage

11 EXAMPLE SEDIMENTS Inappropriate Hydraulic Design 10.5 MW HPP, Vietnam: Desander with turbulent flow pattern inefficiently performing to sediment entrainment (missing coarse racks or baffles) Due to severe abrasion damage runners to be changed every 2 to 3 years Spare runner available at site, but not properly stored "SMALL HYDRO - BIG CHALLENGES" 11

lateral intake, a 2470 m long power tunnel, a 710 m long steel-lined surface penstock and a powerhouse with three

12 EXAMPLE SEDIMENTATION Inappropriate Sedimentation Management 6.7 MW HPP, Switzerland Cascade of three hydropower plants (operation for longer than 80 years) 10 m high weir with a lateral intake, a 2470 m long power tunnel, a 710 m long steel-lined surface penstock and a powerhouse with three generating units Need of extensive rehabilitation due to completely silted-up reservoir and lack of efficient sediment flushing devise "SMALL HYDRO - BIG CHALLENGES" 12

DESIGN Basic Studies Topography Often missing data base or old maps ASTER or World DEM for preliminary assessment of alternatives (potential) Drone survey Field survey at relevant locations Geology

13 DESIGN Basic Studies Topography Often missing data base or old maps ASTER or World DEM for preliminary assessment of alternatives (potential) Drone survey Field survey at relevant locations Geology Walk-over of experienced geologist Engineering aspects Field investigations (drilling etc.) required? Hydrology (Inflow, floods and sediment) Often no flow data series available Empirical approaches or extrapolation Installation of river gauging station? "SMALL HYDRO - BIG CHALLENGES" 13

DESIGN Hydraulics Understanding basics of hydraulics: Optimize the performance of waterways to reduce energy losses Design spillways and flood prevention Design energy dissipation Control erosion and

14 DESIGN Hydraulics Understanding basics of hydraulics: Optimize the performance of waterways to reduce energy losses Design spillways and flood prevention Design energy dissipation Control erosion and sediment transportation Controling phenomena such as: Air, sediment and debris entrainment Surges in long waterways Instability in waterways (transients) Cavitation of structures and equipment Prevent reservoir sedimentation [ESHA 2004] "SMALL HYDRO - BIG CHALLENGES" 14

DESIGN Small Dams and Weirs Small dams are being defined by ICOLD as any dam with: maximum height (H), measured from deepest foundation level to highest structure crest level, less than 15 m, expect

15 DESIGN Small Dams and Weirs Small dams are being defined by ICOLD as any dam with: maximum height (H), measured from deepest foundation level to highest structure crest level, less than 15 m, expect 10 m < H < 15 m, and the following conditions: Dam length more than 500 m, Reservoir storage capacity more than 3 million m 3 Flood discharge more than m 3 /s Unusual characteristics in dam type or foundation Reduced safety requirements [ICOLD 2011] "SMALL HYDRO - BIG CHALLENGES" 15

DESIGN Small Dams and Weirs Good Practices for the design of small dams: Investigation of foundations and excavation of organic and other inappropriate soils at dam foundation Hydrology study

16 DESIGN Small Dams and Weirs Good Practices for the design of small dams: Investigation of foundations and excavation of organic and other inappropriate soils at dam foundation Hydrology study (inflow, flood and sediment) Cohesive materials for embankment, stable during overtopping Use appropriate and durable material for slope protection Standard design for filters and drains Appropriate equipment for construction (compaction) Permanent monitoring of construction quality Access to outlet works during floods and for maintenance No cattle on dam slopes and abutments No pipes through or over embankments Monitoring and routine inspections during dam operation [ICOLD 2011] "SMALL HYDRO - BIG CHALLENGES" 16

DESIGN E&M Equipment Standardized electromechanical equipment including turbine, gear, generator, inlet valve, control-protectionmeasuring systems and complete mechanical and electrical balance of

17 DESIGN E&M Equipment Standardized electromechanical equipment including turbine, gear, generator, inlet valve, control-protectionmeasuring systems and complete mechanical and electrical balance of plant equipment Modular design minimizing number of components and sizes: Single source responsibility Simplification of interfaces Short installation time Short commissioning time Only one software and hardware solution Single source training of customer s operating personal [Andritz 2016] "SMALL HYDRO - BIG CHALLENGES" 17

18 CONCLUSION LESSONS LEARNT Large Hydro versus Small Hydro Topography Hydrology Geology Hydraulic Design Construction Technologies Generation Equipment Large Hydro LiDAR and survey Detailed analysis (inflow/floods/sediments) Investigations Underground structures, model tests, simulations Experienced contractor (sophisticated technologies) Specific specifications (model tests etc.) Small Hydro Drone survey and survey of selected sites Detailed analysis (inflow/floods/sediments) Walk-over, limited investigations Approved design (expert knowledge) Local contractor (simple technologies) Functional specifications (standardized concepts) "SMALL HYDRO - BIG CHALLENGES" 18

19 CONCLUSION LESSONS LEARNT Objective: Satisfactory functional structure at a minimum total cost. Robust design considering availability of resources (construction material, construction techniques and manpower) Use of standardized designs, costing procedures, specifications, and contract documents Standardized design for hydro-mechanical and electromechanical equipment (minimizing complexity and number of interphases) Conceptual design by an experienced consultant (hydrology, geology, hydraulic, geotechn. and structural design, specifications) Detailed design by local consultants (access roads, stone masonry, outline and reinforcement etc.) Flexibility of adjustments (if required) "SMALL HYDRO - BIG CHALLENGES" 19

20 Consulting. Engineering. Projects. Operations.

DESIGN Small (Embankment) Dams Wrong Practices for the design of small dams: Foundations not investigated or investigated to a limited standard Inappropriate hydrology

21 DESIGN Small (Embankment) Dams Wrong Practices for the design of small dams: Foundations not investigated or investigated to a limited standard Inappropriate hydrology study (less data available) Inappropriate soil compaction Seepage control not designed to standard Inappropriate material used (e.g. dispersive clays) Inappropriate equipment used during construction Erodible by-wash spillways, cutback erosion of spillway Inappropriate slope protection No adequate features around outlet pipes No full time construction monitoring No regular inspection during its life No monitoring instruments Adoption of lower cost with higher risk. [ICOLD 2011] "SMALL HYDRO - BIG CHALLENGES" 21

CASE STUDY OKUYOSHINO, JAPAN

SEDIMENT MANAGEMENT CASE STUDY OKUYOSHINO, JAPAN Key project features Name: Okuyoshino Country: Japan Category: bypass channel/tunnel Reservoir volume (original): 15.47 Mm 3 Installed capacity: 1,206 MW