1a 3 duncan wb rehabilitation in challenging environments

8/20/2019 1A 3 Duncan WB Rehabilitation in Challenging Environments

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Hydropower rehabilitationin a challenging

institutional environment

Reynold DuncanWorld Bank Africa Energy Group

Workshop on Rehabilitation of

Hydropower


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Outline

Lessons LearnedGhana Sixth Power Project ( Akosombo)

Zambia Power Rehabilitation Project

(Kafue Gorge and Kariba North)Uganda Second and Third PowerProjects (Owen Falls/ Nalubale)

Iraq Emergency (Dokan andDerbandikhan)


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Lessons Learned

The urgency of rehabilitation usually results infinancing decisions taking place prior toadequate investigations and designs

Limited knowledge by the operators and lack of

proper monitoring and inspection duringoperation contribute to lack of preparedness oncommencement of rehabilitation

Cost overruns and implementation delays can

only be mitigated if the necessary preparatorywork is conducted ahead of investment


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Lessons Learned ctd

Financiers should help advance technicalassistance for proper project preparation

Financiers and Borrowers should be flexibleto accepts changes in design along the way

Rehabilitation should consider the entirepower plant and with repowering possibilitiesLimited operator knowledge and lack of

proper monitoring during operationexacerbate poor preparation for rehabilitation

Consultants alone do not have the necessarycompetencies to conduct the necessaryinvestigations


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Akosombo

First HPP: four of the units (588 MW, with15%overload capacity commissioned1965);additional two units (324MW, with15% overloadcapacity commissioned 1972)

Credit approved 1990 to retrofit the plantincluding the reconditioning of the six runners,rehabilitation of other turbine parts, new

governors, new stator core windings for first fourgenerators and rewinding of other two, newequipment for the overhaul of the electro-mechanical systems and the supply of spare

parts for the five year operation


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Akosombo ctd

The proposed project was prepared by VRA withthe assistance of consultants

The condition of the Akosombo had beeninvestigated by several external experts

A manufacturer and consultant had carried outindependent studies to compare replacement andoverhaul of the turbine runners and concluded thatthe benefit of replacement would be marginal

Above confirmed by an operating utility


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Akosombo ctd

Credit was expected to be fully utilized end-1995but work had just commenced

Original technical solution of refurbishing the

hydro turbine runners at Akosombo abandonedafter one refurbished unit-expected efficiencygains not obtained

Decided to replace the runners instead and IDA

financed the design of the runners and modeltesting

Credit closed with only 28% disbursed;implementation of the new design financed by

others


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Kafue Gorge and Kariba North ctd

Approved February 1998; first WB project in 20 years Rehabilitation of Victoria Fall (108MW), Kariba North

Bank (4 x 150 MW) and Kafue Gorge (6 x 150 MW) Original project design replacement of parts Later realized capacity increases at Kariba North

(120 MW) and Kafue Gorge (90 MW) were possible Kafue consultants had decided not run tests to

determine most probable scope but decide duringimplementation when machines opened

Repowering was least cost option of increasing

capacity (at $200K compared to $1 m at the time) Credit was closed prior to the repowering works,

which were financed by others


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Owen Falls

The plant had been in operation since 1954 Second Power Project Credit approved March 1985 Scope quite complete: underwater repairs, power

station repairs, re-waterproofing powerhouse, dam gateequipment, transformers and ancillary equipment, stator

windings upgrade, refurbishment or replacement of allmoving parts, modernization of I&C, upgrading the 10units from 15 to 18 MW

Original scope omitted dam rehabilitation The timetable too optimistic considering this was the

only power plant and UEB had not undertaken majorconstruction in several years Start-up delayed by 2.5 years due to country-wide strife Original completion date 1990, actual completion seven

years behind schedule


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Owen Falls ctd

(the dam)

Dam suffered alkali-aggregate reaction,designed without proper drainage, and a risk toOwen Falls and all future hydro development,all of which would be downstream

Owen Fall Extension (Kiira Units 1 and 2)approved 1987 included dam rehabilitation butcost overruns caused further postponement

Supplemental loan approve 2000to rehabilitatethe dam


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Dokan and Derbandikhan Emergency

Hydropower Project (ongoing)

Dokan: 400 MW, commissioned 1979

Derbandikhan 249 MW, commissioned 1986

Project design combined urgent repairs and technical

assistance for subsequent rehabilitation Urgent repairs due to years of neglect – financing and

knowledge shortfalls

Urgent repairs include the entire power plants, from the

dams to substations Technical assessment will comprise detailed

assessment of the plants’ condition, dam safety and

feasibility of repowering


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Thank You

1a 3 duncan wb rehabilitation in challenging environments

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