The Saudi Electricity Company (SEC) has received commercial bids for the solar component for the Duba integrated solar combined-cycle (ISCC) power plant.

Spain’s Initec Energia submitted the lowest bid for the solar component on 9 July, according to sources close to the project, and is now the low bidder for the overall project, having recently submitted the second lowest price for the combined-cycle.

MEED reported in June that six groups had submitted bids for the main combined-cycle engineering, procurement and construction (EPC) component of the proposed Duba plant. Spain’s Abener submitted the lowest bid of SR2.05bn ($547m) for the combined-cycle package.

Abener’s bid was 6.8 per cent lower than the SR2.2bn price submitted Initec Energia, the second lowest bidder. However, when combined with the solar component, Initec has now emerged as the lowest bidder for the overall scheme according to sources within the kingdom’s power sector.

Other bidders for the project include the local Alfanar Construction, Turkey’s Gama, and the local Al-Toukhi and National Contracting Company (NCC).

The client received technical bids for the EPC deal in November. The commercial bid deadline was extended a number of times to allow contractors more time to work on submissions.

The Duba 1 ISCC is planned to run on a mix of natural gas and solar energy, and will have a total development cost of $600m. The Duba plant will have a guaranteed total output of 485-550MW, which will include 40-50MW output from the solar system. The planned commissioning date of the plant is 2017.

SEC has tendered the project as a combination of EPC and equipment packages.

In January, SEC awarded the US’ GE the original equipment manufacturer (OEM) contract for the Duba 1 project. GE’s order includes two F-class gas turbines, a steam turbine, generators, heat recovery steam generators, condenser, control system and long-term service agreements.

The Duba project is one of two ISCC schemes that SEC is planning to develop. Contractors are currently working on proposals for the 1,050MW ISCC power plant at the Waad al-Shamal industrial development in the north of Saudi Arabia. The proposed plant will have combined-cycle capacity of 1,000MW and a solar component of 50MW. The plant will use concentrated solar power (CSP) technology, with the client allowing the bidder to select whether to use parabolic trough, power tower or linear fresnel technology.