## 2 Demand-Side Management Classifications and Their Roles in Cost Minimization
### Unpredictable Nature of DERs and the Impact on DSM  
Due to the unpredictable and uncertain nature of renewable DERs, the efficiency of the DSM scheme can be affected. While developing a DSM scheme, the unpredictability and uncertainty associated with DERs should be considered. In [87], the authors investigated a dynamic energy management system for the future smart grid by considering unpredictable renewable distributed energy resources, consumer demand, and energy storage devices. In this work, the authors considered two type of demanded load, i.e., mandatory load and flexible load, with the objective of minimizing the overall cost of the consumed energy. The cost of energy was minimized as follows:  
\[\min\lim_{T\rightarrow\infty}\frac{1}{T}\sum_{t=0}^{T-1}E\{U(t)\} \tag{7}\]  
where \(U(t)\) is a function of the energy consumed at time \(t\) and is given by \(U(t)=f(N(t))\). The variable \(N(t)\) is the amount of electricity that would be generated by the supplier to fulfill the consumer load which is calculated from \[N(t)=P(t)-R(t) \tag{8}\]  
where \(P(t)\) represents the consumer's load at time \(t\), and \(R(t)\) denotes the renewable generated power. The authors further concluded that each user should have bi-directional communication with the utility company, and each consumer has his/her own DERs and storage device. Whenever the consumer has surplus power besides his/her own usage/mandatory load, then by the bi-directional communication can be sold to the main grid which could help to fulfil the demands during peak hours of other consumers [168]. In [112], the concept of DER coordination was explored. The authors used a particle swarm optimization (PSO) technique called CPSO-R to quantify a social welfare (which is a function of cost, PAPR, net benefits, etc.) added by the DERs coordination. With this technique, firstly, each DER is scheduled independently and then all DERs are scheduled collectively in order to find the above described social welfare. Then, on the basis of this value, the consumers schedule their consumption to maximize their net benefits. In this work, the authors presented a smart home case study in which, by applying the CPSO-R, the net benefit of the consumer was maximized by scheduling the controllable DERs according to the scheduling algorithm. In this particular case, it reduced the consumers' energy bills by 16% to 25%. In [97], the authors explored a day-ahead optimization based DSM scheme for consumers with DERs and storage devices. In addition, the authors considered consumers with greater consumption than production or storage. In that scenario, the consumers of this type import energy from the main grid to fulfill their required demands which, in turn, increases the load on the main grid. The proposed scheme reduces the consumption of these users in this scenario by using a game theoretical approach. Through the integration of DERs into the main grid, there is an imbalance in the grid. The authors in [74] considered an imbalanced condition and presented an energy management based on the novel pricing scheme to balance the uncertainty caused by the integration of DERs into the main grid. The novel pricing scheme was obtained by solving a convex linear inequality matrix. In [78], the authors presented a solution for problems occurring during the integration of DERs into the main grid. In the proposed scheme, there is no need for supplier involvement. The DERs generated energy at the consumer premises is used by the consumer and the surplus energy is sold to the nearby needy consumers through by the existing distribution network. The proposed scheme is implemented in the Korean smart distribution management system and is used to minimize the losses of the distribution feeder and to maintain the system's reliability. Another DSM scheme for the displaceable residential load which uses a controller installed at the consumer premises was discussed in [114]. The controller is used for the minimization of the overall energy cost and to improve the reliability of the power system.