Seven companies were prequalified to bid for the power plant in May. They are: France's Alstom, Italy's Franco Tosi, Germany's Voith-Siemens Hydro Power Generation, Austria's VA Tech, the UK's Scott Wilson Kirkpatrick, the London office of the US' GEand the Energy Ministry affiliate Farab. The client is Iran Water Power Development Company (IWPDC), a wholly-owned subsidiary of the Energy Ministry power company Tavanir. The consultant is Moshanir Power Engineering Consultants, also state-owned.

Siah-Bisheh is the largest hydro-electric plant now being planned in Iran. It will comprise two earth-filled dams and an underground power plant. The dams will each contain two turbines of 250 MW each. Construction will take 54 months. The power plant package is expected to be worth around $350 million-400 million.

The civils contract was signed in August for the dam and is now waiting to be approved by the Tavanir board. The successful consortium was led by Kayson and also includes Scott Wilson and the local Soil Engineering. The contract is worth $110 million.

Hydropower is a growth area for Iran, which plans to increase its hydro-electric generation capacity to 7,000 MW from 2,000 MW over the next three years. There are several plants already under construction including Karoon phases 3 and 4, Karkeh and Godvand. Another two phases of Karoon are under study and are expected to be tendered in the coming six months.