Spain’s Abener has submitted the lowest bid of SR2.05bn ($547m) for the main engineering, procurement and construction (EPC) contract for the Duba integrated solar combined-cycle (ISCC) power plant.

The Spanish firm submitted the lowest bid on 25 June for the construction contract for the main combined-cycle component of the proposed Duba plant.

Abener’s bid was 6.8 per cent lower than the SR2.2bn price submitted by Spain’s Initec Energia, the second lowest bidder.

The local Alfanar Construction submitted the third lowest price of SR2.3bn, which was followed by a bid of SR2.6bn from Turkey’s Gama.

Al-Toukhi and National Contracting Company (NCC), both local, submitted bids of SR2.7bn and SR2.9bn respectively.

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.

Bidders are due to submit commercial proposals for the solar element in early July. 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.