The Chizuma and Chasombo project sites in Nkhotakota District with estimated capacities of 40.4 MW each and an equal discharge rate of 40 m3/s, have previously been studied as a cascade of two dams with the upstream Chasombo storage structure providing flow regulation and maximizing guaranteed power capacity and the smaller Chizuma diverting water to an intake for irrigation. Chasombo has a head of 108m and Chasombo has a head of 113.6m. Chizuma is viable only with a storage dam upstream. An alternative option (New Chasombo) that has been explored considers combining Chizuma and Chasombo into one power station with an aggregate capacity of 83 MW.
The consultancy services, which are to be financed by EGENCO, will entail a review and update of the feasibility study and Environmental and Social Impact Assessment (ESIA) conducted in 2012-2013, and preparation of a detailed engineering design and tender documents for a competitive bidding process. The original feasibility study, undertaken from December 2011 by France’s Artelia Eau & Environnement and submitted in July 2013, recommended the construction of a 110 m-high RCC dam at Chasombo with an upstream concrete face, impounding a reservoir with a storage capacity of 960 x 106 m3. Two small saddle dams would be required to close the reservoir at the full supply level and the probable maximum flood (PMF) level. Artelia also proposed a 26 m-high RCC dam for Chizuma. The water conveyance systems for both projects would be completely underground with a 2.16 km-long tunnel supplying the Chasombo powerhouse equipped with two Francis turbines.
The primary goal of this assignment is to update the feasibility study and complete the necessary design and documentation of the projects, as soon as possible, in compliance with the requirements of the World Bank and African Development Bank (AFDB) for development of hydropower projects. The consultant shall review and update the Feasibility Study and Environmental and Social Impact Assessment (ESIA) studies conducted in 2013. The specific objectives of the consulting services include but are not limited to the review and validation of the following: (i) Topographic maps for the dam site, powerhouse site and other relevant project areas; (ii) Geological and geotechnical studies/investigations, including assessing the adequacy of previously excavated test audits at the dam and powerhouse sites. Any gaps identified must be addressed during this study review; (iii) Seismological investigations and studies; (iv) Hydrological and Sediment studies; (v) Model for the dam, spillway and associated headwork structures, including the desanding basin and validating the assumptions made; (vi) Project optimization; (vii) Preparation of detailed engineering design and drawings for all project components; (viii) Power evacuation study; (ix) Project cost estimate and construction plan; (x). Analysis of the financial structure and financing plan; (xi) Economic/financial analysis based on detailed project costs, implementation schedule, risk analysis, etc and (xii) Baselines for the Environmental and Social Impact Assessment (ESIA), scoping, and the preparation of a complete ESIA study. In addition the consultant shall also prepare a comprehensive set of tender documents with all necessary technical and project specific non-technical requirements. The consulting services shall be based on the updated feasibility study and the field investigations and studies carried out as part of this study. The selected consultant can refer to data/information and the past studies but shall be responsible to check, verify and confirm their authenticity. The consultant shall include in the financial proposal all costs required to carry out the activities required under the scope of services and to complete the assignment as per the terms of reference.
Interested consultants must provide information indicating that they are qualified to perform the services. This includes a minimum of fifteen years of experience in conducting detailed feasibility studies of hydropower projects. The experience should cover at least three similar assignments in tropical regions in the past 10 years with two in developing countries, of at least 100 MW.
The tender notice can be downloaded from EGENCO’s website at https://www.egenco.mw/tenders/. Expressions of Interest, in sealed envelopes, clearly marked with subject and procurement reference number (EGC315/EOI/CS/FY2023-2024), must be delivered by 14.00 hours on 5 September to the IPDC Chairperson, EGENCO, Chayamba Building, No.7 Victoria Avenue, PO Box 1567, Blantyre.