Saudi Electricity Company (SEC) has again extended the commercial bid submission dates for its planned 550MW Duba 1 integrated solar combined-cycle (ISCC) plant.

Contractors now have until the final week in June to submit commercial proposals for the ISCC plant.

This is the third time the submission date for commercial bids has been extended. The original deadline for prices was 2 April. The extension is due to contractors requesting more time to work on proposals. In November, MEED reported that SEC had received technical bids for the contract to build the Duba 1 plant on 16 November.

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 40MW to 50MW output from the solar system. The planned commissioning date of the plant is 2017.

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.