Slide 1

Enhancing the Climate Resilience of African

Hydropower and Irrigation Infrastructure

David Groves Zhimin Mao

Robert Lempert

2015 AWRA Annual Meeting Denver, CO

Water and Climate Resilience Center

Slide 2

Work a Part of Recently Completed World Bank Funded Study

1. Continent-wide evaluation of water and energy sectors

2. Water and energy facility scale case studies

Slide 3

Huge Water and Energy Infrastructure Needs Now and Into the Future

• Annual infrastructure investment needs around $80 billion per year

Slide 4

Large investment projects likely to meet much of the need

Program for Infrastructure Development in Africa (PIDA)

• Hydropower generation (>54 GW)

• Water storage (20,000 km3)

• Irrigation canals

Slide 5

How Might Climate Change Affect Africa’s Needs and the PIDA Strategy?

Slide 6

How Might Climate Change Affect Africa’s Needs and the PIDA Strategy?

Potential Change Risk Opportunity Increasing temperatures • Water stress;

higher irrigation needs

Increasing precipitation trends

• Flooding • Higher hydropower production

• Lower irrigation needs

Decreasing precipitation trends

• Lower hydropower production

Increased hydrologic variability

• More severe droughts/flooding

• Lower returns on infrastructure investments

• Higher returns on infrastructure investments

Slide 7

Developed Integrated Modeling System to Evaluate Climate Impacts on Water and Energy Infrastructure

Slide 8

Used Robust Decision Making to Structure Vulnerability and Adaptation Analyses

1. Decision Structuring

2. Case Generation

3. Vulnerability Analysis

4. Tradeoff Analysis

Descriptions of key vulnerabilities

Robust Designs

Alternative Designs

www.rand.org/rdmlab

Slide 9

Applied Framework Across Africa

River Basins Power Pools

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Iterative Analysis Considered Multiple Cases to Isolate Potential Climate Effects

• Investments: PIDA+ •Historical climate Reference Case

• Investments: PIDA+ •Wide range of climate futures (121)

Climate Change, No Adaptation

• Investments: PIDA+ w/ perfect foresight •Representative set of climate futures (6)

Climate Change, Perfect Foresight

• Investments: PIDA+ w/ robust adaptation •Representative set of climate futures (6)

Climate Change, Robust Adaptation

Slide 11

Wide Range of Climate Effects for Southern Africa Power Pool Basins

Slide 12

Wide Range of Climate Effects for West African Power Pool Basins

Slide 13

Significant Negative Impacts Without Adaptation in the South African Power Pool

Hydropower

Irrigation

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Wide Range of Impacts (positive and negative) Without Adaptation in the West African Power Pool

WAPP

Hydropower

Irrigation

Slide 15

Developed Perfect Foresight Strategies for Specific Climate Futures

• Basin level infrastructure adaptations – Planned turbine capacity – Reservoir storage – Mean conveyance irrigation efficiency

• Farm level adaptations – Planned irrigation area – Use of deficit irrigation – Field-level irrigation efficiency

Adaptation limited to adjustments to planned infrastructure

Slide 16

Perfect Foresight Adaptation Can Provide Modest Performance Improvement

Zambezi Hydropower

Economic Benefit from Baseline Projects

Economic Benefit from Adaptation

Scaled Net Revenues

Slide 17

Effects of Adapting in the Wrong Way Are Large

Picking the wrong adaptation Not adapting at all

Slide 18

By Exploring “Regret” Across Futures, Robust Strategies Are Identified

(PIDA+ or Perfect Foresight)

Strategies with low regret • Range of regret for PIDA+

across futures is always positive

• Implies that PIDA+ is not optimal for any future (including historical conditions)

Slide 19

By Exploring “Regret” Across Futures, Robust Strategies Are Identified

(PIDA+ or Perfect Foresight)

Strategies with low regret

Slide 20

Savings from Robust Adaptation Could be Significant In Some Basins

(SAPP) (SAPP) (WAPP) (WAPP) (WAPP) (EAPP)

Slide 21

Costs of Adaptation Are Generally Modest

Slide 22

Summary of Key Findings

• Africa-wide study identified significant potential climate change impacts to the water and power sectors

• Adjusting infrastructure plans can improve performance in climate change futures

• Uncertainty about future climate makes potential regret significant

• Identified robust adaptations can reduce regret and improve outcomes

Slide 23

Limitations and Possible Extensions

• Analysis focuses on large infrastructure

• Small and distributed infrastructure may be: – Less vulnerable to climate – More adaptable and thus have lower

regrets

• Plausible climate futures derived from downscaled global climate models only – May underestimate effects of variability

Water and Climate Resilience Center www.rand.org/jie/centers/water-climate-resilience.html Project Report: http://goo.gl/2iAX4C David Groves groves@rand.org

Slide 25

Study Evaluated Five Diverse Water and Energy Projects Across Africa

1. Lower Fufu Hydropower Project (Zambezi River Basin, Malawi)

2. Batoka Gorge (Zambezi River Basin, Zambia)

3. Mwache Dam (Kwale District, Kenya)

4. Polihali (Orange River Basin, Lesotho)

5. Pwalugu (Volta River Basin, Ghana)

Slide 26

Case Study Projects Face Different Possible Future Climate Conditions

Annual cycle of precipitation

Interannual variability of precipitation

Slide 27

Case Studies Used DMUU Methods to Evaluate Vulnerabilities and Design Robust Alternatives

1. Decision Structuring

2. Case Generation

3. Vulnerability Analysis

4. Tradeoff Analysis

Descriptions of key vulnerabilities

Robust Designs

Robust Decision Making (RDM)

Alternative Designs

Slide 28

Case Studies Demonstrate Approach That Could Be Applied in Feasibility Design Stage

• Case Studies: – Use data from pre-feasibility reports – Based on limited interaction with host country – Use models that were externally validated only

• Results are illustrative

Methodology can be applied by feasibility study team to ensure climate

resilience of final project

Slide 29

This Talk Focuses on the Batoka Gorge Case Study

• Zambezi River

• 181 meter-high dam; 1,680 million m3 storage

• Two power stations – Eight turbines – 1600 MW capacity

• Baseload and peaking capacity benefits – Zambia – Zimbabwe

Does Considering Climate Change Suggest an Alternative Project Design?

Slide 30

Each Case Study Focused on Key Uncertainties, Adaptation Options, and Performance Metrics

1. Decision Structuring

2. Case Generation

3. Vulnerability Analysis

4. Tradeoff Analysis

Descriptions of key vulnerabilities

Robust Designs

Alternative Designs

Slide 31

How Would Each Project Perform Under Different Plausible Futures?

• Climate change

Batoka

Slide 32

How Would Each Project Perform Under Different Plausible Futures?

• Irrigation and urban demands

Pwalugu

Slide 33

How Would Each Project Perform Under Different Plausible Futures?

• Project Benefit Factors – Power purchase agreements – Price for delivered water

• Project Costs – Penalties for under-production or delivery – Irrigation area expansion

Slide 34

Alternative Infrastructure Designs

Considered

• Facility size (dam height and storage capacity)

• Facility capacity (turbines, transfer volumes)

Slide 35

Alternative Designs Compared by Net Present Value

• Benefits – Hydropower production – Irrigation water supply – Volumes of water transferred

• Costs – Capital and O&M costs – Under-performance penalties

Slide 36

Analyses Use DMUU Methods to Evaluate Vulnerabilities and Design Robust Projects

1. Decision Structuring

2. Case Generation

3. Vulnerability Analysis

4. Tradeoff Analysis

Descriptions of key vulnerabilities

Robust Designs

Alternative Designs

Slide 37

Alternative Batoka Gorge Designs Proposed and Costed

35 alternative designs

– 5 dam heights /reservoir storage sizes

– 7 turbine flow capacities

Design cost tool – Estimate capital

and O&M costs for alternative project designs

Slide 38

Alternative Designs Simulated Across Hundreds of Plausible Futures

• Water management model (WEAP) – Estimate runoff from

climate data – Simulate operations of

alternative project designs

– Capture other system constraints (inflow requirements, other demands)

Slide 39

Analyses Use DMUU Methods to Evaluate Vulnerabilities of Alternative Designs

1. Decision Structuring

2. Case Generation

3. Vulnerability Analysis

4. Tradeoff Analysis

Descriptions of key vulnerabilities

Robust Designs

Alternative Designs

Slide 40

We First Identified the Historical Optimal Batoka Design for Reference…

• Highest NPV for historical climate conditions

Slide 41

Then We Evaluated the Vulnerability of this Design to Other Futures

• 145 different climate futures

Slide 42

Tradeoff Analysis Helps Compare and Identify Robust Designs

1. Decision Structuring

2. Case Generation

3. Vulnerability Analysis

4. Tradeoff Analysis

Descriptions of key vulnerabilities

Robust Designs

Alternatives Designs

Slide 43

Different Criteria Used to Measure Robustness

1. Minimize maximum regret

2. Satisfice or a wide range of future conditions

3. Satisfice over a wide range of likelihoods for future conditions

Net Present Value Regret: • Difference between NPV for a particular

design and the best performing design

Slide 44

Batoka Design Minimizing Maximum Regret Depends Upon the Power Purchase Agreement

Slide 45

Satisficing Batoka Design Depends on the Expected Flow and Power Purchase Agreement

Historical Optimal Design

Increased Capacity

Smaller Size & Decreased Capacity

Decreased Capacity

Historical Optimal Design

$1 billion regret threshold

Slide 46

Satisficing Batoka Design Depends on the Expected Flow and Power Purchase Agreement

Historical Optimal Design

Increased Capacity

Smaller Size & Decreased Capacity

Decreased Capacity

Slide 47

What Next?

• Use visualizations to support stakeholder and decision maker deliberation over tradeoffs

OR

• Develop new approaches to mitigate residual uncertainty

Slide 48

In Conclusion: Across All Case Studies We Find…

• Performance of project designs can be sensitive to future climate

• Adaptation can reduce maximum regrets

Improvements in the most favorable futures

Improvements in the least favorable futures

Slide 49

… and Robust Infrastructure Designs

• Are often smaller than the best design for the historical climate

• May be robust over a wide range of climate futures if paired with flexibility in the choice of water or power contracts

Look for the Final Report to be released in the coming months by the World Bank…..