Placement progress at the Roller Compacted Concrete dam for the largest Hydropower plant in Southeast Asia (August 2008)

With an installed capacity of 2'400 MW, Son La Hydropower Plant in the North of Vietnam is the largest hydropower plant in Southeast Asia and is currently under construction (scheduled completion of the project in 2012). The project comprises an approx. 140 m high Roller-Compacted-Concrete (RCC) gravity dam with a RCC volume of ca. 3.1 Mio. m³. RCC placement commenced on January 11th, 2008, the production of total 742'000 m³ until end of June 2008 averaged at 124'000 m³ per month with a peak month of 178'000 m³ in May 2008. In June 2008 the completion of the RCC in part of the dam enabled the handing over of the first power intake sections by almost one month early.

A RCC mix design featuring 60 kg/m³ Ordinary Portland Cement and 160 kg/m³ fly ash from a Vietnamese coal fired power plant was specified in cooperation with Malcolm Dunstan & Associates from the United Kingdoms. The use of this high cementitious RCC and the addition of a highly effective set retarder (initial setting time approx. 22 h) facilitates a fast placement rate and a high quality of the horizontal lift joints with a minimum of preparation effort.

Colenco Power Engineering Ltd (since 2007 AF-Colenco Ltd) is the Sub-consultant to the Vietnamese Engineer Power Engineering Consultancy Joint Stock Company 1 (PECC1) from Hanoi and is responsible for the design of the RCC dam and design supervision during construction.

Son La construction site, June 2008

RCC compaction and finishing with 12t vibratory rollers		Upstream formwork and “first impoundment”

Marco Conrad - Hydropower Plants

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Due Diligence EOS – A Stressful Job Made Pleasant
(July 2008)

In preparation of the upcoming merger between the two Swiss Utilities Atel and EOS, AF-Colenco, along with legal advisors, accounting and financial experts, was asked by Atel to undertake an evaluation of the EOS-activities and power plants, allowing a precise determination of the share that EOS is bringing into this merger. In parallel, a similar team of experts evaluated Atel activities and assets for EOS, with the same purpose. Both, Atel and EOS put at the experts’ disposal a dataroom equipped with technical, legal and financial data, and allowed the counterparties to undertake extensive inspections of power plants which the expert teams considered relevant. Activities started in late April 2008 and ended in early June 2008. AF-Colenco’s project team was composed of highly qualified mechanical, electrical and civil engineers. Apart from more tedious tasks such as data mining and report writing in the EOS-data room in Lausanne and at the home office in Baden, AF-Colenco experts inspected several EOS-hydropower plants located in spectacular mountain landscapes in the Canton of Valais and Vaud in Southwestern Switzerland. Among the regions visited were the Simplon Pass, Zermatt, Val de Dix, Aletsch, Hongrin and the Dents-du-Midi. On each of these visits AF-Colenco’s team was accompanied by competent and very hospitable plant-maintenance and -exploitation staff, who contributed their part to making this project not only an interesting but also a very pleasant one.

Simplon – Serra Dam (Valley of Zwischenberg)		Electra Massa – Gebidem Dam (downstream of the Aletsch Glacier)
Grande-Dixence Complex – Reservoir at Ferpècle pumping station (Val de Ferpècle)		Salanfe Dam and Reservoir from the helicopter (Municipality of Salvan, surrounded by the Dents-du-Midi)

Thomas Ihly - Hydropower Plants