**6. Deployment of Utility-Scale Battery Energy Storage**

The Eskom BESS project involves implementing outcomes at several locations in various operating units (OUs). Sizes of the results range from 1 MW to 60 MW. The standard size of an installation is 4 MW/16 MWh, which equals an estimated total of 90 installations. To optimize the usefulness of the BESS, all results will have a primary function and supporting roles that are "stacked benefits" in nature. As an illustration, a unit designed primarily for capex deferral during peak times in the winter will be available for operations such as frequency support at any time and peak clipping in the summer. The maximum discharge period will be 4 h. Figure 15 illustrates the steps used to appear in a technical investigation.

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**Figure 15.** Process flow for the BESS project.

*Step 1:*

Wherever possible, supply-delayed investment and congestion supervision were given priority because these are the most enticing applications.

#### *Step 2:*

Active OU recognized potential sites, where appropriate. Substations located in electrically distant operational units were chosen in cases where local improvements could not be immediately realized. Prioritizing areas that relieve congestion upstream and reduce failures was one endeavor. In addition to replacing peak energy (kWh) and demand, these locations will supply gains and losses (kW).

*Step 3:*

In this stage, the business benefit of installing BESS is compared to other viable options (such as adding new supply/transmission substations and feeders, installing voltage regulators, adding more peaking power generators, etc.), as well as whether the investment will be recouped within a reasonable amount of time. The case for the project is made on the basis of both direct and indirect benefits, such as lower distribution costs for bulk purchases and lower production costs overall.

#### *Step 4:*

Conducting technical due diligence on potential locations is the first stage of this cycle. This entails showcasing a number of system planning studies, such as the worst case (maximum charging and discharging) load flows, dynamic time-series training, and quality of distribution studies. Conceptual plans for efficient locations have been carried out. These are based on standard BESS yard and station yard layouts, but the winning engineering, procurement, and construction (EPC) contractor are responsible for finishing them at the detail design stage. This phase also saw the creation and approval of the following technical specifications:

BESS equipment; AC equipment; General BESS and substation yard; Protection and control; Distributed energy resources management system (DERMS); Application performance monitoring (APM) tool.

In order to ensure a smooth transition between system circumstances and BESS stationing, the DERMS will be implemented into the SCADA. A "BESS fleet" will be successfully run by it. The life management of the BESS divisions is important, since some interactions tend to diminish over time, making the technical advancements less fully implementable. Therefore, it is crucial to check the unit's longevity, especially the chemical storage unit. The APM tool is used to achieve this. Authorizing involves locating land and directing environmental impact assessments in accordance with the relevant laws.
