Several European and Asian engineering companies submitted bids to construct gas booster compressor stations at Saudi Aramco’s Haradh and Hawiyah gas plants, sources told Reuters.

Hyundai Development Co Engineering & Construction (HDEC), GS Engineering and Construction, Tecnicas Reunidas, Saipem, Shandong Electric Power Construction Corp (SEPCO), Larsen and Toubro (L&T), CTCI, and Petrofac all submitted bids for the project.

This project is part of a $4 billion plan to increase capacity at the plants. At present, gas accounts for 50% of Saudi Arabia’s energy production, but officials hope to increase it to 70%, according to Reuters.

Saudi Aramco is also nearing completion of the first phase of its expansion of Saudi Arabia’s primary gas pipeline and expects to finish phase one of the project by the end of the year.

As part of its Vision 2030 plan, Saudi Arabia is seeking to diversify its energy sources and lessen its dependence upon crude oil. Its cabinet of ministers recently approved a proposal to develop a national plan for the use of atomic energy.