Rades C Combined-Cycle Power Plant

Rades C combined-cycle power plant is a 450MW natural gas-fired plant under construction at Rades, approximately 10km east of Tunis, the capital city of Tunisia.

The power plant is owned by the Tunisian state-owned electric and natural gas utility company Société Tunisienne de l’Electricité et du Gaz (STEG).

The $345m combined-cycle power project broke ground in February 2018. It is being developed with the help of Japanese Official Development Assistance (ODA) loan. Scheduled to commence full operations in 2020, it will contribute approximately 10 % of Tunisia power production capacity.

The power project is expected to generate 150 permanent and 2,000 temporary jobs.

Rades C power project development details

The Government of Tunisia (GOT) approached the Japan International Cooperation Agency (JICA) for a Japanese ODA loan for the Rades C combined-cycle power plant in August 2012, after a series of preliminary discussions.

STEG submitted the environmental impact assessment (EIA) of the project to Tunisia’s National Agency for the Protection of the Environment (ANPE) in December 2013 and received no objection letter for the same in February 2014.

JICA approved the ODA loan for Rades C project in July 2014.

STEG awarded the engineering, procurement and construction (EPC) contract for the project in June 2017.

Construction works started in early-2018 with the start of plant’s partial operations expected in 2019.

Rades C power project site details

Rades C combined-cycle power plant is being built in 13.3-acre government-owned land in the same site where STEG-owned 340MW Rades A and 360MW Rades B thermal power plants are located. Rades A and Rades B plants have been operational since 1985 and 1998 respectively.

The project site, located adjacent to the Port of La Goulette, also houses Carthage Power’s 471MW Rades II combined-cycle plant, Tunisia’s first Independent Power Project (IPP), which commenced operations in 2002.

Rades C combined-cycle power plant make-up

The 450MW combined-cycle power plant comprises a 380MW Mitsubishi Hitachi Power Systems (MHPS) F-class M701F gas turbine, a heat recovery steam generator (HRSG) and a steam turbine from Mitsubishi.

Other facilities of the power plant include a gas fuel system, a secondary diesel fuel system, water-cooled condensers, and a cooling tower.

The power plant will use water from the adjacent d’Ammenee canal for cooling.

Water treatment facilities for the Rades C project include a desalination and a demineralisation water plant.

Rades C gas turbine details

Designed for 50Hz power generation, the M701F gas turbine offers a net combined-cycle efficiency of more than 62%.

The air-cooled M701F gas turbine comes with a 17-stage compressor with variable inlet guide vanes (VIGVs), low NOx cannular combustor, two-bearing supported rotor and a four-stage reaction turbine.  The ramping capacity of the gas turbine is 38MW a minute.

Gas supply for Rades C plant

Rades C plant will receive gas supply via a 16in-diameter new pipeline connected with the existing gas station being used by Rades A and B and Rades II power plants.

STEG has gas supply agreements with Tunisia’s state-owned oil and gas company Entreprise Tunisienne d’Activité Pétrolière (ETAP) and the Algerian state-owned petroleum company Sonatrach.

Electricity transmission

Rades C electricity output will be distributed from the nearby Rades III switchyard to the 225kV Rades II substation via a 0.4km single-circuit transmission line and to the 225kV Kram substation via a 9km double-circuit transmission line.

The entire transmission infrastructure for Rades C plant including the switchyard and transmission lines are being built as part of a separate project financed by European Investment Bank (EIB).

Financing for the Rades power plant

The annual interest rate for the $345m Japanese ODA loan for the Rades C project is 0.6%. The loan is repayable in 40 years with a grace period of ten years.

Contractors involved

A joint venture of Mitsubishi Hitachi Power Systems (MHPS) and Sumitomo Corporation was awarded the EPC contract for the Rades C combined-cycle power plant in June 2017.

MHPS provides the gas turbine, heat recovery steam generator and the steam turbine for the plant.

Sumitomo offers balance of plant and will undertake all civil and installation works of the project.

GAMA Power System was subcontracted by Sumitomo in July 2017 to provide infrastructure design as well as supply equipment including gas compressor, auxiliary boiler, desalination system, water treatment plant, transformer, fire-fighting, liquid fuel system and so on.