designing climate resilient hydropower sector: a case of nepal
TRANSCRIPT
Designing Climate Resilient Hydropower Sector: The Case of Nepal
Divas B. Basnyat and Dibesh Shrestha
Nepal Development Research Institute (NDRI)
Kathmandu, Nepal
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Climate-Resilient Water Management Approaches: Adaptation in an Age of
Uncertainty
A webinar series from UNESCO, AGWA, & ICIWaRM
Webinar 5 | Climate Risk Assessment on Hydropower
Wednesday, 10 March 2021
08:45-10:15 UTC / 14:30-16:00 Kathmandu
Outline
• Hydropower in Nepal
• Climate and hydrological regime
• Rationale
• Methodology
• Key messages• Vulnerability Assessment
• Adaptation pathways
• Barriers and Entry points
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Hydropower in Nepal
Divas B. Basnyat and Dibesh Shrestha, 10 Mar 2021
78°E
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Hydrological/Climate Regime
Indian Summer Monsoon (80% rain in JJAS)
Hydrology: -Rainfall-runoff-Glacier melt-Snow melt-Baseflow
• Catchment response – glacier (>~5,000m) and snow-fed (>~3,000m), rain-fed
• Geo-hazards– Landslides, Landslide Dam Outburst Floods, GLOFs, Flash Floods and Riverine Floods, Debris Flows
Snow / Glacier Melt contribution to Discharge( %)
H. Biemans et al. (2019)
Divas B. Basnyat and Dibesh Shrestha, 10 Mar 2021
RationaleClimate Risk Assessment Approach
• GCM-based Top-Down or A priori scenario definition
• Bottom-up Approach or Ex post scenario definition
Challenges
• Highly variable topography and climate of Nepalese Catchments
• Future changes are highly uncertain
• Current actions for future risks
What is needed is a Robustness-based approach emphasizing preparedness for a range of possible futures.
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Future Climate
VulnerabilityAssessment
Impact Assessment
ClimateRisks
Top-down Approach Bottom-up Approach
Climate Driven
System Driven
Divas B. Basnyat and Dibesh Shrestha, 10 Mar 2021
Types of Uncertainty• Climate change uncertainty
• Most models project increased monsoon precipitation, but no agreement on winter precipitation
• Wide variations on level of warming (temperature)- glacier/snow melt, evapotranspiration
• Precipitation extremes projected to increase – sedimentation, floods, landslides
• Elevation dependent warming
• Other uncertainties
• Regulatory and policy- tariff, national market, cross-border trading, power mix (including variable renewables- solar, wind)
• Project variables - Cost and time overrun, discount rates
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Clim
ate
Pro
ject
ions
: 2040-2
059
RX
1d
ay
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Methodology
• Step 1- Vulnerability Assessment using the bottom-up Climate Risk Assessment (CRA) approach;
• Step 2- Identification of Adaptation Options using the Adaptation Pathways approach;
• Step 3- Understand and address mainstreaming of adaptation in the hydro-power sector through Institutional Analysis and identification of entry points and barriers.
NDRI, PAC & GCAP, 2016 7Divas B. Basnyat and Dibesh Shrestha, 10 Mar 2021
Stakeholder-defined Performance Indicators
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Stakeholders Key Performance Indicator (KPI)
Government Policy Maker, Regulator
Power System Reliability and Quality, Marginal Cost, Dam Safety, Design Standards, Social and Environment Impacts
Financial Institutions/ Lending Agencies
Project Economics (Cost and Benefit Stream), Social/Envi Impacts, Dam Safety
Project developer (private and public)
Project economics (NPV, FIRR), Adaptation Cost, Seasonal Energy Generation and Reliability (firm, secondary)
Project Designer, Hydrologists, Engineers
Design Flood, Geo-hazards, GLOF, Sediment, Water Availability (Hydrology)
Communities, Environmental Stakeholders
Dam Safety, Flood and Geo-hazard Risks, Flow Variations, Environmental Flows
Resiliencein terms of:
• Safety• Water/Energy
Security• Economics
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Stress Test – Case Study
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Yie
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hr)IRR
Catchment Response – Hydrological Model
Hydropower Model
Economic Model
Climate Input
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Sediment Concentration
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Current climate and hydrological variability is a major challenge for Nepal’s hydro- sector
However, there is large variation in this variability
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• Higher variability in smaller catchments, higher in rainfed than in snow-fed catchments
• Run-of-river (ROR) projects more affected by variability than storage projects
• Sediment load generally high, particularly on some catchments
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hr)
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High – snow fed
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-20% P, +3 T Extreme Case
Storage > 50 % of Monsoon Runoff Storage = 8 % of Monsoon Runoff
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Storage Projects
ROR Projects
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The greatest impact of climate change is from increased climate induced hazards, rather than from changes in water availability
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• Financial performance (IRR) of hydro projects designed under current tariff and PPA rates are within performance threshold for projected change
• Increased climate induced hazards – sediment, extreme floods, GLOFs, LDOFs- more important risk and will be exacerbated by climate change
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Distance (km)Tsho Rolpa Thulagi LakeImja Tsho Upper Marsyangdi ADudh Koshi Storage Tamakoshi III / II
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GLOF Risk
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The impact of climate change on hydropower sector is additional to other factors
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In the short-term, current and new plants affected by:
• Current variability, climate- induced geo-hazards, and
• Uncertainty on institutional and regulatory issues related to tariffs and pricing, export opportunities, construction costs (and risks of delays and over runs) and project financing
For future plants (after 2030), the impacts of climate change could be much more significant,
• However, design of these plants need not be finalized now: there is opportunity to learn more about emerging trends and changes, and adjust these investments
• This requires preparation and action today, e.g. on hydro-met data and monitoring
IRR 12%
IRR 11.2%
Base
CC
Learn, Act later
IRR 10.9%
IRR 11.4%
Adapt in design
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Current power system suffers from inefficient power mix –resulting in high economic costs
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Run of River Projects
Storage Projects
• Projects designed under current regime (pricing, market and regulatory policy) may not perform as designed with future changes (uncertainty)
• Current power mix - 10% Storage and 80% RoR; Future – approx. equal capacity (47% each) with energy mix at 72% for ROR and 18-22% for storage
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ix,
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Base Case ROR Baae Case Storage
CC Case ROR CC Case Storage
System ExpansionPlan
Adaptation Pathways
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Iterative climate risk management Low or no-regret options
1. Addressing existing climate variability i.e. current adaptation gap
Options that bring immediate economic benefits, and build future resilience to future changes
2. Considering future climate change in immediate decisions with long life-times
Options that allow reductions in future risks, e.g. risk screening, low cost over-design, flexible design, provide greater robustness
3. Planning for future climate challenges, with uncertainty and an iterative (learning) in mind
Iterative plans for future major changesMonitoring programs and iterative portfolios to address future risksLearning over time
Current plants
Planned plants
Future risks
What
act
ion t
o t
ake n
ow
?
Divas B. Basnyat and Dibesh Shrestha, 10 Mar 2021
Institutional Context, Barriers and Entry Points
• Stakeholder roles and responsibilities, exposure to CC risks, mechanism to implement adaptation, and their influence
• Barriers: investment, institutions, policy (PPAs, regulations)
• Mainstream adaptation into the institutional and policy/sector landscape e.g. policy intervention addressing vulnerabilities to the specific context, location, project size and type (not one size fits all)
• Include climate in existing activities (e.g. Risk screening in Design Guidelines, System Planning, EIA process, PPAs, Dam Safety, Risk Sharing Mechanism) to make it climate smart, rather than stand-alone
• Invest to learn: monitoring, research and pilots, to improve future decisions and planning
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Thank you!
Divas B. Basnyat, [email protected]@gmail.com
Dibesh Shrestha, [email protected]
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NDRI Water and Climate Program: https://ndri.org.np/project_cat/water-climate-program/Weather Generator Tool: https://ndri.org.np/ourproject/weather-generator-and-climate-change-scenario-generator-for-climate-risk-assessment/
Middle MarshyangdiHEP