*4.12. Backup Supply*

In UPS mode, a BESS solution can be employed as a backup energy source. There are numerous engineering production inroads in the SA market in the backup energy and energy security market [50]:


A look into the BESS market in South Africa is illustrated in Table 3.


**Table 3.** BESS in South African Market [50].

Due to the fact that networks are typically developed specifically for each application, hydrogen storage and vanadium redox flow batteries have not gained the necessary access to markets. These situations often involve substantial capital-scale applications, and the viability of the project is determined throughout its life cycle by the levelized cost of storage (LCOS). Initial analysis shows that lithium iron technology may have the most significant commercial presence. Lithium iron phosphate (LiFePO4) is currently the dominant technology, mostly because of its low production costs, established performance rankings, and evaluated effective stability. The majority of Li-ion-linked base systems are

used in off-network applications where the end-user has limited or no access to service energy or where energy security is crucial for the continuity of business operations. These outcomes often take the shape of a hybrid mini-network with integrated renewable production (mostly solar PV), diesel production, and battery storage (see this case study). Energy storage system installation has increased in high-end homes and businesses as a way to mitigate the effects of load shedding.

Some of the technical challenges can be circumvented as tabulated in Table 4 using the relevant application, control algorithm and duration, which is critical.


**Table 4.** BESS control algorithms and application.

It can be observed that by using a Li-ion battery over a Pb acid battery, the issues of power smoothing, load shaving, frequency regulation, PV plant dispatchability and energy arbitration can be circumvented.
