7.3.2. Deterministic

The deterministic techniques examine various electrical configurations, system components being altered, and how they need to be optimized based on preset principles. A deterministic technique is a direct approach to cost [130] and capacity [131,132] alongside the optimization process investigated by some other analysis.

#### 7.3.3. Rule-Based Optimization

The rule-based optimization (RBO) method defines an expected solution, such as fuzzy logic. In accordance with the following literature [131,133–136], optimization of BESS sizing is realized using fuzzy logic. Based on the research, a fuzzy-based method was adopted to reduce both the RES and the cost of BESS [137]. According to the data, an ideal BESS reduces microgrid costs by 3.2 percent, and battery longevity significantly affects MG costs. The primary advantage of utilizing a fuzzy optimizer is that either the total number of parameters is unknown or the scale of the optimization issue is unaffected by any change [138].

#### 7.3.4. Mathematical-Based Optimization

The most comprehensive method is mathematical modeling when it comes to finding the solution to the BESS sizing-related problem. This approach for determining the optimal size of the BESS is categorized as linear programming (LP), nonlinear, or mixed-integer programming (MILP). Mathematical optimization is approached in three different ways, namely DP, convex programming (CP), and second-order cone programming (SOCP). Since the DP model separates this process into several different time slots, and the solutions are recognized at each level, it is both possible and advantageous to combine time-varying elements. In some literature, this model was used to maximize BESS size [111,139–141]. The CP technique also has the advantage of discretionary independence. Furthermore, its optimization strategy is employed in [142,143], to achieve the best possible results in minimizing the linear objective function. It is necessary to intersect the affine linear manifold with the product of second-order cones. Based on the literature published by [144,145], SOCP is used to size BESS.

#### 7.3.5. Heuristics

Heuristic strategies allow suitable, non-ideal arrangements to be applied in real time. There is no mathematical foundation that is effective in obtaining optimal solutions, instead, approaches such as nature-inspired algorithms are used. These include GA [146], PSO [147], bat algorithm [148], and taboo search [149]. The key benefits of using heuristic approaches are flexibility, high accuracy, and computation timelessness.
