The growing need for 10 MW-plus power plants
There is a growing trend among large power users to install power generating capacity exceeding 10 MW, and South Africa-based Zest WEG is serving this need with a range of its in-house solutions. Bernard Mitton, Business Development Consultant at Zest WEG explains.
“Historically, power plants of above 10 MW have not been that common, but recently we have noted more requests,” says Bernard Mitton, Business Development Consultant at Zest WEG. Mitton highlights that businesses looking to sustain or increase their production need a reliable power supply. In countries like South Africa, this means ensuring production can continue during the regular spells of national loadshedding, which is taking a severe toll on output levels in many sectors.
“In other parts of Africa, the demand for these large power plant solutions is also driven by economic growth,” he says. “Users may be starting projects in areas without power, or they may want to augment supply from an unreliable national grid,” he adds.
A solution Zest WEG typically suggests is a modular system that allows the customer to implement projects in phases. These power plants allow for future expansion, or redundancy can be added as required.
“Each power plant system we develop is unique to the customer’s requirements and specific site conditions,” he explains. “A typical 10 MW system will have eight to 10 generators installed, each generator within a containerised solution or a dedicated power plant room.”
These systems will usually generate power at 400 V, with a step-up transformer to up to 11 kV. Alternatively, power can be generated directly with an alternator output at up to 11 kV. The generators connect to a power plant switchboard at a voltage of 22 kV, from where the power is distributed to power the various loads the customer requires.
“We can design and manufacture 11 kV switchboard solutions within a container, an E-house or a plant room,” says Mitton. “Each power plant also has a dedicated power plant control room with a site-specific SCADA system designed to control and monitor the power plant.”
In Zest WEG’s generator facility in Cape Town, the company has the capabilities to load test all generators – from 400 V through to 11 kV – in line with customer requirements. This includes performing a step load test and synchronising the generators to each other to ensure all setpoint, engine performance and efficiencies match design expectations.
“Our tests, modifications and site-specific setups are useful to illustrate site conditions,” he says. “For example, the user may have time constraints on how long the generators take to synchronise and apply load.”
He emphasises that arriving at an optimal power solution starts with listening carefully to customers and understanding what they require. Where the customer is looking for guidance on the best way to achieve what they need, Zest WEG’s dedicated power plant sales engineers meet with the customer’s technical team to discuss technical and commercial aspects of the project. This is usually followed by site visits and pre-engineering, so multiple solutions can be presented.
“This all helps to understand the project requirements and to develop the best proposal for the customer’s application,” says Mitton. Sizing of the generating units is a critical area that needs specific information on starting methods, operating philosophy and site-specific conditions. Where this is not readily available, Zest WEG sends a team to site to investigate. This process could range from measuring individual loads to using a power analyser on a plant. The site layout and respective loads are also noted for the sizing process.
What makes the difference to the customer, Mitton argues, is Zest WEG’s depth of in-house engineering expertise, combined with the capability to design and deliver full turnkey projects. This includes detailed design engineering and project management, along with manufacturing the solution, on-site construction, installation and commissioning.
“Our in-house capability is what makes our solutions so appealing to customers,” he says. “With multiple departments in Zest WEG – and further depth of expertise in our parent company WEG – we can run the whole project from start to completion.”
For a power plant project, for instance, Zest WEG provides custom-designed generator solutions, as well as the associated cabling, transformers and medium voltage switchgear. The containerisation and related sundries are also handled in-house.
“By taking responsibility for this wide scope, we can give customers peace of mind and reduce their risk,” he says. “They can work with a single supplier, rather than subcontracting to multiple parties and having to manage how they all interact.”
Under the Zest WEG umbrella, all the primary equipment required for such a project is manufactured in-house and carefully coordinated between the engineering, project management and site installation teams. This ensures that installation and commissioning take place on schedule and within budget. The company has conducted numerous successful projects across Africa, designing and supplying solutions that integrate with the customer’s new or existing site.
“Our strategic presence across Africa ensures that our umbrella of support reaches far across the continent to be there when the customer needs us,” he says. He concludes by highlighting that Zest WEG’s experienced teams can find solutions for the most challenging projects. The range of expertise within each in-house project team ensures that the customer’s needs are analysed in detail to best match the customer’s onsite needs.
