Mechanical Technology September 2015

⎪ Sustainable energy and energy management ⎪

Selecting the optimum generator set

Bradley van der Spreng, project engineer and Craig Bouwer, sales engineer at Zest WEG Group’s Generator Set Division talk about the importance of carefully considering the company’s overall power requirements before deciding on a backup power solution to accommodate a shortfall.

understanding of the many issues sur‑ rounding standby power. “Companies are generally unaware of how to assess the standby power requirements of a facility or building. By implication, this suggests that companies are also often unaware of what the optimal solution for a given application should be.” A standby power solution is an im‑ portant capex decision that needs to be considered carefully in terms of the com‑ pany’s overall requirements. Moreover, the supplier needs to have the necessary technical expertise and relevant experi‑ ence to offer a customised solution. A key consideration for a standby power solu‑ tion is to understand the environment in which the generator set has to function. Original equipment manufacturer Zest WEG Group’s Generator Set Division has a dedicated facility in Cape Town and offers generator sets ranging from 20 kVA units up to 250 kVA as off-the- shelf products and 300 to 2 000 kVA individual customised units as well as multiple sets are available to achieve turnkey solutions in excess of 12 MVA for large-scale applications or projects. The company has supplied a large number of bespoke generator set solutions based on the specific application and environment in which they operate. “A couple of recent examples include

A view inside a containerised generator set from Zest WEG Group’s Generator Set Division. the containerised three-generator unit we designed and manufactured for DRA Minerals’ Liqhobong Diamond Mine in Lesotho and a turnkey power station for AVI Group’s Indigo Brands. At Liqhobong, we designed a generator set container with a collapsible snow roof. When the roof is collapsed it facilitates easy transportation and, once deployed on site, prevents the build-up of snow on top of the container and the subsequent blocking of the louvres,” says Bradley van der Spreng, project engineer, Zest WEG Group’s Generator Set Division. The scope of supply on the Indigo Brands project comprises three 1 000 kVA generator sets and three 1 000 kVA transformers. “What makes this project unique is that Zest WEG Group’s Generator Set Division is design‑ ing a custom built distribution system and electrical panel for synchronisation. The company is also supplying a 23 000 litre bulk fuel storage system to support this installation,” adds van der Spreng. The successful implementation of these projects hinges on the company’s ability to determine potential solutions for the customer. Amongst these are consid‑ erations for sound restructuring methods, fuel systems, electrical reticulation and interfacing, the load and the duration that this load is required to be powered. “The type of load and the total power drawn should be measured by a qualified team from the generator supplier prior to recommending a particular diesel generator set. Following this, accurate load calculations can be carried out and a suitable system recommended. We look at the entire electrical infrastructure and

Bradley van der Spreng, project engineer and Craig Bouwer, sales engineer at Zest WEG Group’s Generator Set Division.

T he current power constraints facing South Africa and Africa have resulted in companies being requested to cut their power consumption by at least 10% in order to alleviate the pressure on the overburdened transmission and distribu‑ tion infrastructure. This appeal will, of necessity, result in companies seeking alternative power sources to accommo‑ date their energy requirements shortfall. However, cautions Craig Bouwer, sales engineer at Zest WEG Group’s Generator Set Division, there is an apparent lack of

The containerised generator sets for Liqhobong Diamond Mine in Lesotho incorporate a collapsible snow roof which, when deployed on site, prevents the build-up of snow and subsequent blocking of louvres.

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Mechanical Technology — September 2015