ELC Electroconsult S.p.A. - Projects

Nationwide Construction Project - Timor Leste


The Project aims to supervise the construction works for the new national transmission network and new generation power plants. Two new power plants, based on diesel engines, have been installed to provide the country with about 250 MW. About 700 km of 150 kV transmission lines and eleven HV substations have been erected to make the power available all over the country. The feasibility study for some additional systems have also been developed, such as a submarine cable connection with Atauro island, and a separate 20 MW power plant for the enclave of Oecussi.

Works assigned to ELC consist of assistance in the EPC Contract negotiations, design review, factory inspections and site supervision during installation of mechanical & electrical equipment.






Ethiopia - Power Transmission

Design and construction of first 400 kV transmission lines and substations connecting the new Gilgel Gibe II 420 MW HPP to the Ethiopian grid:

- New 400 kV OHTL connecting Gilgel Gibe II HPP-Sabeta (230 km long)

- New 400 kV OHTL connecting Gilgel Gibe II HPP – Gilgel Gibe I HPP (45 km long)

- About 20 km of 230 kV Double circuit OHTL Connecting the substations Sebeta (old) with Sebeta (New)

- Construction of New 400/230 kV substations of Gilgel Gibe I HPP (new) and Sabeta (new)

- Extension of existing 230 kV substations Sebeta (old) and GG I HPP (old).



ITAIPU hydroelectric project


ltaipù is at present the largest hydroelectric project in the world, in terms of installed capacity and energy production. Despite its huge reservoir, the large river discharge makes it essentially a run-ofriver plant, with the powerhouse operating round the clock to supply base energy to the systems of South and South-East Brazil and Paraguay. Studies started in 1971 with the reconnaissance of the binational stretch of the river, and construction commenced in 1976, being essentially completed in 1983, when the reservoir was filled. The installation of the 18 generating units, at an average rate of three units per year, was complete in 1990. Among the different peculiar aspects of the project, the following are especially significant from the technical point of view:

- Difficult hydraulic problems were faced for the planning of the river diversion, particularly for the design of the cofferdams, two rockf ill structures about 70 m high, built almost completely underwater. - The structural design of the dam required extensive studies, including mathematical, structural and geomechanical models.

- The size of the generating units was pushed to the limit to minimise the cost of the equipment and the length of the powerhouse, taking into account the reduced space available in the riverbed. The design of the equipment had also to solve difficult technical problems raised by the binational character of the project, as the frequencies of the Brazilian and Paraguayan networks are different. - As the financial charges represent a huge part of the total investment, the strict respect of the construction planning was a paramount condition, often requiring the updating of the design to specific construction needs in order to minimise difficulties and keep the implementation schedule.

Beles Multipurpose Project

The Beles Multipurpose Project is located in the south-western bank of Lake Tana, some 350 km north-west of Addis Ababa and 70 km west of Bahar Dar, and is aimed to increase energy and power supply to the national grid.

The Project foresees the construction of a single stage power scheme with a total installed capacity of 468 MW, given by four Francis turbines to be installed in an underground powerhouse under a total gross head of about 335 m.  The average annual generation capability is 2050 GWh/y.  The hydropower plant can be excluded for irrigation purposes by the means of an underground by-pass.

Apart from a 820 m long approach channel, the project develops completely underground for a total length of about 20 km. A pressure headrace tunnel approx. 12 km long conveys water, up to 160 m3/s, from Lake Tana into the underground powerhouse, accomodating the four Francis turbine – generator units. The restitution into the Jehana River, a small tributary of the Beles River, is assured by a tailrace tunnel 7.3 km long, running free-flow.

The underground works consist of 1) a powerhouse cavern 105 m long x 19 m wide x 40 m high, 2) a transformers cavern 60 m long x 16 m wide x 13 m high, 3) two TBM excavated tunnels (headrace and tailrace respectively) characterized by an inner circular section of 7.2 m diameter, 4) an underground penstock approx. 340m long, 6m to 2.8m internal diameter, including steel lined pressure shaft 274m high, high pressure tunnel and manifold, 5) a surge shaft with a diameter of 18 m and a depth of 91 m, 6) a ventilation and cable shaft, 7) an access tunnel to the powerhouse, 1.2 km long and 8) an irrigation by-pass diverting up to 77 m3/s flow. The outdoor works are characterized by 400kV switchyard, concrete intake and outlet structures, river diversion works and regulating weirs along the Jehana River and more than 40 km access roads.


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