MURRAY AND ROBERTS POWER AND ENERGY – MAINTAINING KUSILE’S LIVE UNITS

Murray & Roberts Power & Energy (MRPE) is the main subcontractor at Eskom’s Kusile power station and was contracted to erect six super critical boilers, with a scope that included the boiler main structure, the boiler and its related pressure parts, supplementary piping, coal bunkers, fuel burners, ducting systems and the associated mechanical systems to feed coal and reticulate air.

The project has to date logged many millions of work-hours (equating to several human lifetimes) employing the local community and assisting families for many years. At peak MRPE employed over 3 500 people. The first unit, Kusile 1, or colloquially known as K1, was synchronised to the national grid late in December 2016. In the interim, Unit 2 (K2) has been synchronised, as well as K3. The fourth unit (K4) is in active mechanical commissioning. K5 is in the final stages of construction, with K6 short on its heels and destined to be mechanically complete by mid-2020. For MRPE, mechanical completion means that MRPE has completed its construction scope and will be able to hand over the last unit to the client, Mitsubishi Hitachi Power Systems Africa (MHPSA), who will commission the power station once Eskom has installed all the electrics, controls and measurement systems.

MRPE provides active support and expertise to MHPSA during the commissioning phase of each unit, where systems are energised, tested and integrated, so that the boiler unit can be effectively operated. The commissioning support requires broad application of MRPE’s skills, ranging from general labour, to boiler making and welding, basic maintenance of plant operations, often on a 24-hour or standby basis.

Any power station, no matter how well run, requires maintenance. MHPSA is obliged to provide maintenance as part of the manufacturer’s guarantee, and after a period of 18 months, that responsibility passes to Eskom. It has been of strategic importance for MRPE to be recognised as the best contractor to perform this work and to change the market perception that MRPE is primarily a constructor, and not active in the support of a live station. The maintenance of a power station is conducted under a general outage, in which the boiler unit is shut down, allowed to cool, and various systems are inspected and repaired or subjected to preventative maintenance. An outage varies in duration, but a comprehensive outage typically lasts between one and three months. The planned outage for K1 and K2 was at the end of 2018, shortly after a raft of planned national outages (load shedding), when the grid could ill afford to sacrifice generating capacity. However, this planned work had to be done to avoid a later, unexpected and unnecessary outage due to possible system failures.

After a protracted, competitive and thorough openmarket tender process, bidding against renowned local and international competitors, MRPE proved its credentials to MHPSA as the most appropriate contractor to conduct maintenance and repair works at Kusile, with an overwhelming local understanding and context. The excellent work performed in commissioning the units was a useful platform and reference to motivate MRPE’s technical bid. The scope required repairs to various systems, primary being the Gas Air Heater (GAH), two of which operate in tandem on each unit. This component is akin to an industrial air mixer, and uses hot exhaust air to pre-warm cold intake air, thus reducing the fuel burn and improving the efficiency of the boiler. It is to a boiler what a heart is to the human body. The GAH had shown excessive wear on its casing or shell, and required an upgrade due to a revision of the design, following operation experience gained at both the Kusile and Medupi power stations.

Associated to the GAH, were repairs to ducting systems and mills. The five mills per unit, designed to crush coal prior to combustion within the boiler, had been exposed to accelerated wear and needed repair and replacement of the crushing interface, which is made of hardened steel wheels that crush coal in a corresponding steel track. This required the removal of moving parts, most weighing several tonnes, and the replacement and reinstallation of various components.

MRPE sourced and employed local teams of artisans, engineers, quality inspectors, planners, human resource and safety personnel, with the correct management to successfully conduct the works, on a turnkey basis. As the work was undertaken, further systems that required maintenance were identified and additional crews were employed to repair operational damage. Despite tight deadlines, an annual December break and intense attention from both MHPSA and Eskom, the MRPE crews were able to complete the work and cement a reputation as the contractor of choice who should maintain the boilers that we built.

As a consequence, further outage and maintenance works have been awarded to MRPE, ideally positioning the company to generate ongoing and repeat revenue at Kusile and Medupi, post construction completion. MRPE is subsequently engaged on further maintenance and repair works on all three active units at Kusile, with increasing expertise in maintenance of rotating mechanical equipment. These reference projects add depth to MRPE’s service offering and support the strategy to be the first choice partner in maintaining the sub- Saharan Africa’s power generation fleet.

MURRAY & ROBERTS POWER & ENERGY ACQUIRES OPTIPOWER PROJECTS

Murray & Roberts Power & Energy recently acquired OptiPower Projects to facilitate entry into the high and medium voltage transmission, distribution and substation sector in South Africa and sub-Saharan Africa.

The next growth market for Murray & Roberts Power & Energy will be transmission. Low electrification rates and a lack of access to power and energy for citizens in large African economies, as well as vast geographies and scattered populations, will further drive this growth.

OptiPower Projects has the technical capability to deliver transmission, distribution and substation projects in the region and have access to specialised plant and equipment to offer a solution to specialised construction and refurbishment projects in this sector.

Its technical capability combined with the global relationships, balance sheet strength and engineering excellence of Murray & Roberts Power & Energy, will provide access to opportunities across the African continent.