Medupi 6 mainframe Skeleton at night
The public Minister Lynne Brown has announced (18 February 2015) that Medupi’s Unit Six turbine is now running at optimum speed.
This is the first turbine that has been built since the last power station was built over 20 years. We have achieved 3000 rpm, which is a significant milestone in the commissioning process and it’s now to be followed by the last step, which is the electrical test on our generator, explains Roman Crookes, General Manager for Medupi Power Station.
Synchronisation will occur within the next few weeks post these electrical test, and it means the first of the 800MW will slot into the national grid, adds Crookes.
Medupi Power Station’s 6 Units set to add 4800 MW to the National Grid
Medupi Power Station, a Greenfields coal-fired plant project located on the west of Lephalale, Limpopo Province, South Africa is currently under construction as part of Eskom’s new build programme set to address the electricity demand and supply challenges facing the country.
The Greenfields coal plant project will comprise of six units with a gross nominal capacity of 800MW each, resulting in a total capacity of 4 800MW. The power plant utilises a super critical boiler and turbines, technology designed to operate at higher temperature and pressures than Eskom’s previous generation units for greater efficiency.
Medupi power station has been designed as a an environmental friendly project as it utilises supercritical technology, direct dry cooling technology, flue gas desulphurisation, pulse jet fabric filters and low NOx burners, water and air pollution, air cooled condensers, and fauna and flora.
Since the plant will utilise the supercritical technology to improve the plant efficiency, the higher efficiency of supercritical boilers as designed for significantly higher steam temperatures and pressures resulting in better use of natural resources. It will result in burning less coal per megawatt leading to emission of less carbon dioxide and other gases into the atmosphere.
The plant also make use of direct dry cooling technology which releases virtually no cooling water into the atmosphere providing a significant benefit in terms of water consumption. The power station is earmarked to use approximately 0.16 litres of water per kWh of electricity produced and this is expected to increase by 0.2 litres of water per kWh when the flue gas desulphurisation (FGD) plant is retrofitted to Medupi.
The project will also entail a Flue gas desulphurisation (FGD) as a retrofit and thus making it one of the environmental friendly coal-fired power stations. It will also include pulse jet fabric filters and low NOx burners. The low NOx burners on its boilers are designed to minimise the production of nitrogen oxides in the furnace.
The plant is designed in a manner that seeks to mitigate air as well as ground water pollution and this will be achieved through the lining of the coal stockyard and ash dumps, enclosed mill bins and fully enclosed transfer houses with dust extraction systems.
In addition, the law grade steam exhausted from the low pressure turbines and temperature is sent to the air cooled condenser and is then pumped through the feed water heaters back to the boiler to start the cycle over again. The essential part of using this system is on condensing the steam in order to pump the water back to the boiler for reuse.
Unit 6 is the first of six – 800 MW units at Medupi, and is scheduled to deliver stable commercial base-load power into the grid by mid 2015. The second unit at Medupi is currently scheduled for handover by mid/ end 2016, with the remaining four units following at six-monthly intervals thereafter, taking final completion of the 4, 800 MW Medupi power station to mid/ end 2018 at the earliest.
The synchronisation of the first Medupi power station station’s six units comes at a time when the country is facing serious electricity challenges, the collapse of a silo at Majuba power station in Mpumalanga as well as unexpected breakdowns, which result in the power grid being strained.
Since the project is constructed on an 883 hactare farm which was previously used for game and cattle grazing, a thorough nature conservation exercise had to be effected to preserve endangered species. Indigenous trees, snakes, birds, animals were relocated, and for instance trees were replanted at a special nursery at the adjacent Matimba Power Station. In preserving the fauna onsite, the project put in place measures such as animal crossovers on the overland coal conveyor system to allow for the free movement.
The project which commenced in 2007 has invested approximately R2, 3 billion in infrastructure development in the Lephalale area and has seen the construction of 995 houses and buying of 321 houses, and building of a new pre-school, supply of medical equipment to the surrounding clinics, upgrading of the electricity infrastructure, construction of the Paarl sewerage treatment plant with R11.5 million spent on upgrading of the initial 2.2 km of the D1675 road leading to the site.
Eskom has continued to invest in the community and together with Exxaro they will spend more than R150 million in upgrading and repairing Nelson Mandela road as well as tarring Kuipersbult road.
The project has improved the lives of many in the region as 17 000 people have been employed at peak with 650 set to be employed permanently upon completion of the project.
The development with an estimated budget of R98, 9 billion excluding interest during construction but including escalation and transmission integration costs is set reach R125.5 billion to complete. The first of the six units of the plant are set for synchronisation by end of 2013 with each of the remaining five units to be synchronised at approximately eight month intervals.
Once complete the project will make use of the coal that will be delivered from Grootegeluk mine through an overland conveyor system to the Medupi coal stockyard. The conveyor as the sole supply line will supply 10 000 tons of coal.
