Medupi Coal-Fired Power Station, South Africa

Medupi is a dry-cooled coal-fired power station under construction in Lephalale, South Africa. Formerly known as Project Alpha and Charlie, the plant's construction began in August 2007. It is being developed by Eskom, South Africa's state-owned power corporation, at an estimated cost of R100bn.

The power plant will have six units that will together generate 4,800MW. The first unit is scheduled to be commissioned in early 2012. The remaining units will be commissioned at regular intervals of nine months, with the last due for completion in 2015. The plant will be the largest dry-cooled coal-fired power station in the world. It is expected to be operational for nearly 50 years.

Plant details

The plant will cover 883ha on a site that was previously used for sports and cattle grazing. The area is near Matimba power station and the plant will be similar to Matimba in terms of operation, design and size. Medupi's main power plant and related infrastructure will occupy nearly 700ha. The remaining land will be used for ancillary services, including ashing facilities.

The plant will be 130m high and 500m wide. The stacks will be nearly 200m high. No cooling towers will be installed if direct cooling technology is adopted. Other facilities will include a coal stockpile, an ash dump and transmission lines that will connect the power plant to the national electricity grid.

The plant will accommodate six boilers, each powered by an 800MW turbine. The units will be installed with 390 switchgears.

Medupi's boilers will be more efficient and operate at higher temperatures and pressures than previous generation boilers. For cooling, combustion and reduction of pollution, the plant will adopt a range of technologies. It will be developed as a zero-liquid effluent discharge station that continuously monitors emissions.

The plant will source coal from Exxaro's Grootegeluk coal mine, a local coalfield at the north end of the site. Coal will be delivered to the plant via a conveyor.

Construction

The plant will be constructed in a phased manner to meet the growing demand for electricity in South Africa. The first phase, which began in 2007, will include the construction of the first three units. It will also include site clearing through controlled blasting.

Project finance

The project is being financed through funds provided by the African Development Bank (AFDB). On 25 November 2009 AFDB approved a R20.7bn loan to source and install the boilers and turbo generators. The loan, thought to be the biggest AFDB-sanctioned loan in South Africa, was given directly with a sovereign guarantee from the South African Government.

Contractors

The project's two main contracts were awarded to Hitachi of Japan and Alstom (renamed ACTOM in 2009) in November 2007. Valued at R33.6bn, the contracts are the biggest commercial contracts ever awarded by Eskom. The boiler contract, which is worth R20bn, was awarded to Hitachi Power and joint venture partner Hitachi Power Europe.

Hitachi Power Europe will also oversee the offshore works of the project, including plant design and engineering and supply of vital components and high-grade materials. It will provide supervision when the plant is in its building and commissioning phase. For construction work and pressure part manufacture Hitachi Power has partnered with Murray and Roberts and DB Thermal.

Alstom was awarded the contract to supply all medium-voltage switchgear for Medupi. The contract, valued at R275m, includes 640 switchgear units of 280 x 12kV and 360 x 17.5kV. The first switchgear is scheduled for delivery in October 2010, with the final delivery due in 2013.

Other contracts related to the structural steel, mechanical, electrical, instrumentation and piping of six air-cooled condenser (ACC) units were awarded to GEA Air Cooled Systems.

Expansion

Medupi is part of Eskom's capacity expansion programme that is designed to increase Eskom's service offering to South Africa. Medupi's peak generation capacity, expected to be reached in 2016, will increase Eskom's overall capacity by more than 10%.