rapid assessment of potential improvements in water...
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Rapid Assessment of Potential Improvements in Rapid Assessment of Potential Improvements in Water Management through Hydropower Water Management through Hydropower
RehabilitationRehabilitation
Presented by:Presented by:
Gregory A. ThomasGregory A. ThomasNatural Heritage Institute * San Francisco, CANatural Heritage Institute * San Francisco, CA
World Bank Energy Week 2009: March 31World Bank Energy Week 2009: March 31stst –– April 2April 2ndnd
Location of Major DamsLocation of Major Dams
ChinaRest of Asia
North AmericaWestern Europe
AfricaEastern EuropeSouth America
Central AmericaAustralasia
Number of Large Dams
Impacts of Hydropower Dams on Impacts of Hydropower Dams on River Ecosystems and Livelihoods:River Ecosystems and Livelihoods:
Reduces flow during natural flood periodsReduces flow during natural flood periods
Increases flow during dry periodsIncreases flow during dry periods
Disconnects the river from the floodplainDisconnects the river from the floodplain
Fragments the river systemFragments the river system
Targeting Natural Flow Patterns
ProductsProducts
1.1. Develop, Develop, ““test drivetest drive”” & refine for other & refine for other applications a applications a Rapid Assessment ToolRapid Assessment Tool
2.2. Create reoperation opportunity list Create reoperation opportunity list –– Africa Africa focusfocus
3.3. Suggest reoperation scenarios for select dams as Suggest reoperation scenarios for select dams as examplesexamples
MethodMethod
1.1. Utilize readily available data & documents to Utilize readily available data & documents to perform initial screeningperform initial screening
2.2. To resolve uncertainties, conduct inTo resolve uncertainties, conduct in--country country interviews in selected countriesinterviews in selected countries
KenyaKenyaEthiopiaEthiopiaCameroonCameroonNigeriaNigeria
Low
Pot
entia
l for
Reo
pera
tion
Seasonal Storage: Is the active storage capacity of the target reservoir more than 25%* of the
mean annual inflow into the target site/ species habitat?
STORAGE VS. RUN-OF-RIVER
Daily Storage:Does the dam store and release water on a daily
basis into the target site to meet peak power demand.and/or
FLOODPLAIN AND RESERVOIR USESCan land uses and aquatic interests in the downstream floodplain and reservoir area
be modified/managed to accommodate changes in water management?
ECOSYSTEM, LIVELIHOOD and FOOD PRODUCTION BENEFITS (Target site/ species)Does the target dam control flows into any of the following:
No No
Siting, Designing and (Re)operating Hydropower Dams for Improved Environmental Performance
* Provisional figure
depending on local conditions.
TURBINE CAPACITYIs there excess turbine capacity during
peak inflow events?
TURBINE RETROFITIs it feasible to add turbine capacity?
OTHER IMPAIRMENT FACTORSAre there other factors in the downstream environment which preclude environmental restoration?
No
No
Yes
Yes
Yes
Yes
No
POWER VARIABILITY Is seasonal power variability
tolerable?
ConsiderSITE LEVEL REOPERATION
COMPLEX/ CASCADEIs the facility one of a complex or cascade of hydropower facilities in the same basin?
INSTITUTIONAL MECHANISMSIs there an institutional mechanism for coordinating cascade management?
ConsiderCASCADE/ COMPLEX REOPTIMIZATION
Yes
Yes
EFFICIENCY GAINSCan the power output per unit
of water be increased?
PUMPED STORAGE/ RE-REGULATION
Is there a good downstream location for a new re-regulation
reservoir? Or up gradient location for a pumped storage facility?
Yes
Yes
GRID REOPERATIONAre there other sources of power in the grid that can provide substitute peak or
seasonal low runoff power?
GRID INTERCONNECTIONAre there other sources of power in
adjacent grids that can supplant some fraction of hydro-power during the
seasonal low runoff period(s)?
ConsiderGRID LEVEL REOPTIMIZATION
No
Yes
Yes
No
Yes
No
Yes
Yes
No
No
No
Low
Pot
entia
l for
Reo
pera
tion
No
No
Yes
No
Yes
Low Potential for Site Level Reoperation
Low Potential for Cascade or Grid
Level Reoperation
No
Yes
Consider for reoptimization?
Country Yes Maybe No Total
Côte d'Ivoire 3 2 1 6
Morocco 3 1 15 19
Kenya 3 0 3 6
Tanzania 2 2 0 4
Ghana 2 0 0 2
Cameroon 1 5 1 7
Guinea 1 3 0 4
Tunisia 1 2 2 5
Mali 1 0 2 3
Burkina Faso 1 0 1 2
Togo 1 0 1 2
Angola 0 2 7 9
Nigeria 0 2 7 9
DRC 0 2 7 9
Ethiopia 0 2 3 5
Mozambique 0 2 2 4
Number of dams considered for reoptimizationNumber of dams considered for reoptimizationConsider for reoptimization?
Country Yes Maybe No Total
Sudan 0 2 2 4
Zambia 0 1 4 5
Zimbabwe 0 1 0 1
South Africa 0 0 5 5
Algeria 0 0 4 4
Mauritius 0 0 4 4
Madagascar 0 0 3 3
Congo 0 0 2 2
Egypt 0 0 2 2
Gabon 0 0 2 2
Malawi 0 0 2 2
Lesotho 0 0 1 1
Liberia 0 0 1 1
Sierra Leone 0 0 1 1
Swaziland 0 0 1 1
Uganda 0 0 1 1
Yes Maybe No TotalTotal 19 29 87 135
Low
Pot
entia
l for
Reo
pera
tion
Seasonal Storage: Is the active storage capacity of the target reservoir more than 25%* of the
mean annual inflow into the target site/ species habitat?
STORAGE VS. RUN-OF-RIVER
Daily Storage:Does the dam store and release water on a daily
basis into the target site to meet peak power demand.and/or
FLOODPLAIN AND RESERVOIR USESCan land uses and aquatic interests in the downstream floodplain and reservoir area
be modified/managed to accommodate changes in water management?
No No
Siting, Designing and (Re)operating Hydropower Dams for Improved Environmental Performance
* Provisional figure
depending on local conditions.
TURBINE CAPACITYIs there excess turbine capacity during
peak inflow events?
TURBINE RETROFITIs it feasible to add turbine capacity?
OTHER IMPAIRMENT FACTORSAre there other factors in the downstream environment which preclude environmental restoration?
No
No
Yes
Yes
Yes
Yes
No
POWER VARIABILITY Is seasonal power variability
tolerable?
ConsiderSITE LEVEL REOPERATION
COMPLEX/ CASCADEIs the facility one of a complex or cascade of hydropower facilities in the same basin?
INSTITUTIONAL MECHANISMSIs there an institutional mechanism for coordinating cascade management?
ConsiderCASCADE/ COMPLEX REOPTIMIZATION
Yes
Yes
EFFICIENCY GAINSCan the power output per unit
of water be increased?
PUMPED STORAGE/ RE-REGULATION
Is there a good downstream location for a new re-regulation
reservoir? Or up gradient location for a pumped storage facility?
Yes
Yes
GRID REOPERATIONAre there other sources of power in the grid that can provide substitute peak or
seasonal low runoff power?
GRID INTERCONNECTIONAre there other sources of power in
adjacent grids that can supplant some fraction of hydro-power during the
seasonal low runoff period(s)?
ConsiderGRID LEVEL REOPTIMIZATION
No
Yes
Yes
No
Yes
No
Yes
Yes
No
No
No
Low
Pot
entia
l for
Reo
pera
tion
No
No
Yes
No
Yes
Low Potential for Site Level Reoperation
Low Potential for Cascade or Grid
Level Reoperation
No
Yes
ECOSYSTEM, LIVELIHOOD and FOOD PRODUCTION BENEFITS (Target site/ species)Does the target dam control flows into any of the following:
ECOSYSTEM, LIVELIHOOD and FOOD ECOSYSTEM, LIVELIHOOD and FOOD PRODUCTION BENEFITS PRODUCTION BENEFITS
Does the target dam control flows into any of the following:Does the target dam control flows into any of the following:
Broad Alluvial Floodplains
Estuaries Deltas
Wetlands
• RAMSAR/ wetland supporting sustenance or livelihoods?
• (Former) floodplain utilized for agriculture, grazing, fishing, etc.?
• Habitat for species with economic, cultural or sustenance value?
• Delta or estuary supporting livelihoods or sustenance?
• Park, wildlife refuge or other protected area?• Flow dependent Important Bird Area?• Habitat for a flow-dependent endangered
species?• World Heritage site?
Floodplain Wetland
Estuary Delta
Low
Pot
entia
l for
Reo
pera
tion
FLOODPLAIN AND RESERVOIR USESCan land uses and aquatic interests in the downstream floodplain and reservoir area
be modified/managed to accommodate changes in water management?
ECOSYSTEM, LIVELIHOOD and FOOD PRODUCTION BENEFITS (Target site/ species)Does the target dam control flows into any of the following:
No No
Siting, Designing and (Re)operating Hydropower Dams for Improved Environmental Performance
* Provisional figure
depending on local conditions.
TURBINE CAPACITYIs there excess turbine capacity during
peak inflow events?
TURBINE RETROFITIs it feasible to add turbine capacity?
OTHER IMPAIRMENT FACTORSAre there other factors in the downstream environment which preclude environmental restoration?
No
No
Yes
Yes
Yes
Yes
No
POWER VARIABILITY Is seasonal power variability
tolerable?
ConsiderSITE LEVEL REOPERATION
COMPLEX/ CASCADEIs the facility one of a complex or cascade of hydropower facilities in the same basin?
INSTITUTIONAL MECHANISMSIs there an institutional mechanism for coordinating cascade management?
ConsiderCASCADE/ COMPLEX REOPTIMIZATION
Yes
Yes
EFFICIENCY GAINSCan the power output per unit
of water be increased?
PUMPED STORAGE/ RE-REGULATION
Is there a good downstream location for a new re-regulation
reservoir? Or up gradient location for a pumped storage facility?
Yes
Yes
GRID REOPERATIONAre there other sources of power in the grid that can provide substitute peak or
seasonal low runoff power?
GRID INTERCONNECTIONAre there other sources of power in
adjacent grids that can supplant some fraction of hydro-power during the
seasonal low runoff period(s)?
ConsiderGRID LEVEL REOPTIMIZATION
No
Yes
Yes
No
Yes
No
Yes
Yes
No
No
No
Low
Pot
entia
l for
Reo
pera
tion
No
No
Yes
No
Yes
Low Potential for Site Level Reoperation
Low Potential for Cascade or Grid
Level Reoperation
No
Yes
Seasonal Storage: Is the active storage capacity of the target reservoir more than 25%* of the
mean annual inflow into the target site/ species habitat?
STORAGE VS. RUN-OF-RIVER
Daily Storage:Does the dam store and release water on a daily
basis into the target site to meet peak power demand.and/or
Controlling FlowsControlling FlowsStorage capacity large relative to annual inflowNo substantial intervening tributariesNo substantial intervening dams planned
Low
Pot
entia
l for
Reo
pera
tion
ECOSYSTEM, LIVELIHOOD and FOOD PRODUCTION BENEFITS (Target site/ species)Does the target dam control flows into any of the following:
No No
Siting, Designing and (Re)operating Hydropower Dams for Improved Environmental Performance
* Provisional figure
depending on local conditions.
TURBINE CAPACITYIs there excess turbine capacity during
peak inflow events?
TURBINE RETROFITIs it feasible to add turbine capacity?
OTHER IMPAIRMENT FACTORSAre there other factors in the downstream environment which preclude environmental restoration?
No
No
Yes
Yes
Yes
Yes
No
POWER VARIABILITY Is seasonal power variability
tolerable?
ConsiderSITE LEVEL REOPERATION
COMPLEX/ CASCADEIs the facility one of a complex or cascade of hydropower facilities in the same basin?
INSTITUTIONAL MECHANISMSIs there an institutional mechanism for coordinating cascade management?
ConsiderCASCADE/ COMPLEX REOPTIMIZATION
Yes
Yes
EFFICIENCY GAINSCan the power output per unit
of water be increased?
PUMPED STORAGE/ RE-REGULATION
Is there a good downstream location for a new re-regulation
reservoir? Or up gradient location for a pumped storage facility?
Yes
Yes
GRID REOPERATIONAre there other sources of power in the grid that can provide substitute peak or
seasonal low runoff power?
GRID INTERCONNECTIONAre there other sources of power in
adjacent grids that can supplant some fraction of hydro-power during the
seasonal low runoff period(s)?
ConsiderGRID LEVEL REOPTIMIZATION
No
Yes
Yes
No
Yes
No
Yes
Yes
No
No
No
Low
Pot
entia
l for
Reo
pera
tion
No
No
Yes
No
Yes
Low Potential for Site Level Reoperation
Low Potential for Cascade or Grid
Level Reoperation
No
Yes
Seasonal Storage: Is the active storage capacity of the target reservoir more than 25%* of the
mean annual inflow into the target site/ species habitat?
STORAGE VS. RUN-OF-RIVER
Daily Storage:Does the dam store and release water on a daily
basis into the target site to meet peak power demand.and/or
FLOODPLAIN AND RESERVOIR USESCan land uses and aquatic interests in the downstream floodplain and reservoir area
be modified/managed to accommodate changes in water management?
Floodplain and Reservoir UsesFloodplain and Reservoir Uses
Can land uses and aquatic interests in the downstream floodplain and reservoir area be modified/managed to accommodate changes
in water management?
1. Reoperate cascade or complex to neutralizeEg. Tana River cascade in KenyaEg. Sanaga River complex in Cameroon
2. Upgrade efficiency of generation to maintain dry season power output
Note: reliability penalty compared to wet season output
3. Compensatory reoperation of grid systemEg. Akosombo Dam on Lower Volta in Ghana
Three conceptual pathways for Three conceptual pathways for compensating for change in schedule of compensating for change in schedule of
power generationpower generation
Costs:Increased turbine capacityUpgraded turbine efficiencyIncreased transmission capacityIncreased thermal generationRemoval of floodplain constraints, levees
CostCost--Benefit BalanceBenefit BalanceBenefits:
Improved livelihoods/food productionIncreased total power outputImproved interannual reliabilityReduced flood riskClimate change adaptation
Potential for beneficial reoperation is largeAt least 20% of dams
Siltation reversal and prevention is of major importance in many cases
In many cases, effects of existing dams will be overwhelmed by effects of new dams
Major ConclusionsMajor Conclusions
Siting:Higher in systemTributaries
Design:Smaller relative to inflowOverdesign powerhouse and transmission
Operations:Run of river rather than storageRedefine role in generation mixFloodplain development policies are essential
Provides potent lessons for Provides potent lessons for decisions on new damsdecisions on new dams
NNATURAL ATURAL HHERITAGE ERITAGE IINSTITUTENSTITUTEN H IN H I
Thank you for your attention!Thank you for your attention!