MechChem Africa May-June 2023

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.

“H istorically, power plants of above 10 MW have not been that common, but recently we have noted more requests,” says Bernard Mitton, Busi ness 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

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

implement projects in phases. These power plants allow for future expansion, or redun dancy 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

Each modular generator consists of an engine with a cooler and an alternator, all mounted onto the base frame. Systems will usually generate power at 400 V, with a step-up transformer to up to 11 kV, but power can be generated using an alternator that can directly deliver up to 11 kV.