Bids are invited by 23 August for an EPC contract for the design, procurement, construction, testing and commissioning of the project, including civil works and the supply of electro-mechanical equipment and hydraulic steel works.
The project will involve the addition of 10 MW to the existing 20 MW hydropower plant, which is located downstream of the Maguga dam on the Komati river in the Hhohho region of Eswatini. It will entail the construction of a new reinforced concrete powerhouse equipped with a 9.9 MW horizontal Francis turbine and a generator, together with relevant ancillary structures (erection bay, steel superstructure, and a main 60 ton overhead gantry crane for equipment installation). A new bottom outlet structure is foreseen, which includes the outlet system for the twin 1.8 m diameter outlet pipelines that depart from the existing intake tower. The twin 1.8m diameter outlet pipelines are to be provided with an ecological flow release system, which will operate for long period flows up to 4 m3/s.
The existing station, which was completed in 2006, was developed and is currently operated by the Komati Basin River Authority (KOBWA), a bi-national agency created by the governments of South Africa and Eswatini. The plant is generally used as a peaking station, and only produces base power when Maguga dam spills. The operation of the dam and the discharged flows are regulated in accordance with the Treaty on the Development and Utilization of the water resources of the Komati rivers (1992). Its main purposes are to regulate the flows for downstream agricultural uses, supply domestic water to the town of Piggs Peak, provide water resource from the Komati to industrial and agricultural users within Eswatini and South Africa, ensure environmental flows and develop the site’s hydropower potential.
The works for the construction of the power facility extension shall include all works for the seamless integration of the new generating unit and relevant step-up transformer bay into the existing station.
The electro-mechanical supply under this contract includes a single horizontal shaft Francis turbine, rated 10.6 MW, one butterfly type main inlet valve (MIV), one frequency governor and one hydraulic power unit for governor and MIV, one horizontal axis synchronous generator, rated 12.2 MVA, a static excitation system and switchgears, one 66 kV air insulated switchyard bay for the new step-up transformer and one three-phase 11/66 kV, a 12.2 MVA ONAN/ONAF step-up transformer. It also includes mechanical Balance of Plant, control, protection, telecommunication and metering systems, powerhouse auxiliary electrical equipment including excitation and unit auxiliary transformers and one 400 V, 150 kVA emergency diesel generating unit and an Uninterruptable Power Supply (UPS) system.
The scope of work covers all control equipment for communication with the national dispatching centre, and includes a gateway to dispatching centre, Automatic Generator Control Devices, SCADA, and point-to-point testing of data communication. The main hydraulic steel structures for the bottom outlet include two butterfly valves DN 1800, two steel pipes DN1800 each 32m long including a transition DN1800-DN1200; two fixed cone valves DN1200 and two ecological flow release systems (each consisting of butterfly valve DN600, steel pipe l=22m and fixed cone valve DN400), and one 15 ton overhead travelling gantry crane. For the powerhouse it includes two steel pipes DN 1200 each 30 m long, one bifurcation, one steel pipe DN1800 10 m long from bifurcation up to MIV, one draft tube stoplog (2.6 m x 2.6m) and one draft tube monorail crane (10 ton).
The civil engineering works include an outdoor powerhouse, designed for accommodating one horizontal Francis turbine and generator, step-up transformers and switchgear; a bottom outlet structure, including the two penstocks and all valves. In addition the contract entails geological and geotechnical investigations as required; topographic survey and setting out works, site environmental mitigation works; construction of any temporary roads; slope protection works, where necessary; and supply and construction of complete substation with the annexed foundation structures.
Bidders may be a private entity, a state-owned enterprise or any combination of such entities in the form of a joint venture under an existing agreement, or with the intent to enter into such an agreement.
The base reference documents for the design to be performed by the contractor are the employer’s requirements and a basic design prepared in 2024 by Studio Ing. G. Pietrangeli of Italy. The full tender documentation can be viewed at: www.eec.co.sz/tenders
Bidders must send an original of the proposal, as well as three copies by 11.00 hours local time on 23 August to Eswatini Electricity Company, P.O. Box 258, Eluvatsini House, Mhlambanyatsi Road, Mbabane, H100, Kingdom of Eswatini. For clarification and further information contact: Bongani Chauke, Eswatini Electricity Company, Tel: +268 2409 4165; Email: bongani.chauke@eec.co.sz; www.esppra.co.sz.
