Optimal energy storage management for self-consumption groups

We study the optimal management of a photovoltaic system's battery owned by a self-consumption group that aims to minimize energy consumption costs. We assume that the photovoltaic system is composed of a photovoltaic panel and a battery, where the photovoltaic panel produces energy according to a certain stochastic process. The management of the battery is the responsibility of a group administrator, who makes the joint decision to either store part of the photovoltaic energy production and sell the remaining energy at the electricity spot price, or discharge part of the energy stored in the battery and sell it in the electricity market. Inspired by European Union and Italian legislation, which promote incentives for energy transition and renewable energy production, we assume that the group receives a monetary incentive for the virtual self-consumed energy, defined as the minimum between the power bought from the grid to satisfy the group's power demand and the energy sold to the market. In this case, the energy sold by the group is a mix of part of the photovoltaic production that is not stored and part of the energy discharged from the battery. We model the problem as a stochastic optimal control problem, where the optimal strategy is the joint charge-discharge decision that minimizes the group's energy consumption costs. We find the solution numerically by applying a finite difference scheme to solve the Hamilton-Jacobi-Bellman equation associated with the value function of the optimal control problem.