# Virtual Power Plant Optimization in Smart Grids: A Narrative Review
## 4 VPP Applications in Smart Grids
### Energy Services Delivery
Some of the services it provides to customers are efficient system automation, energy backups in case of emergencies, permanent monitoring, and stability [71]. It also offers services where the customer can design a VPP. Battery energy raised a lot of interest among multiple companies such as PG&E, OhmConnect, SPACs, Portland General Electric (PGE), and Vermont. All of them have pilot projects that create renewable energy using batteries. The architectures and maturity of the projects differ, but all these companies provide services for residents that will offer stability and backup energy in case of special events and a decrease in the cost [72]. Figure 4: VPP coordination for energy service delivery. The impact of the VPP services and the benefits brought by this type of architecture for energy management has been studied in the literature [75]. In [57], a framework for the coordinated management of VPPs is described, considering correlated demand response. The VPP operating costs are minimized while assuring the power system stability and power quality. The optimization problem is addressed using a low-risk two-stage stochastic strategy considering renewable generation and energy price uncertainty. With the aid of the extensive advanced simulations conducted, the benefits of the proposed model in minimizing the VPP costs and improving the power quality have been illustrated. The authors of [60] give attention to a hierarchical model proposed for simultaneous modeling of scheduling and VPP energy management problems. As the stochastic nature of the scheduling inputs is given, power production and load demand waving are modeled method. As a result, the final model is presented as a stochastic mixed-integer linear programming model. By using demand response, it is possible to cover the fluctuations at the minimum cost [76]. Moreover, the possibility of power transactions between the adjacent microgrids is investigated in the scheduling model, preventing unreal power exchanges. From the simulation result, it is possible to reduce the supply costs, thus leading to a significant increase in profit of the VPP. Making a transition towards renewable energy gives small, distributed generators a huge impact, thus leadig to the use of actively stabilized distribution grids [4]. The need for coordinating the distributed generation in VPPs forces their schedules to be managed as a single plant [77]. This problem can be addressed by using agents and flexible control methods [78]. The key for coordinating such systems is the underlying communication infrastructure. In [53], the authors provide a direction where energy assets and batteries are integrated into a VPP that serves as a service layer for the market by analyzing the technical and economic possibilities. They study the economic efficiency of the model, and the influence of energy price and renewables, showing that positive net value can be reached in several years. The authors of [55] highlight the necessity to create alternative electricity management systems and a solution would be the use of VPP services that can provide energy to places where the resources are limited. It may be necessary to combine several distributed renewable energy generation units, and electrical vehicle charging stations. They are coordinated by considering the prediction of consumed power and of the power produced, allowing the management of the volume of energy in a balanced way. The prophet model is implemented for energy prediction and technical analysis purposes. In [62], we have defined a fog computing solution for the creation and management of VPPs to provide ancillary services. Energy meters are used for prosumers' monitoring while a fog layer manages the local energy systems through cooperative models. The energy services are integrated through a cloud layer considering frequency reserves, local constraints, and profit maximization. The energy markets allow for efficient and flexible energy trading, in a competitive environment.