Operation scheduling of prosumer with renewable energy sources and storage devices

Abstract

The reduction or elimination of incentives for the installation of decentralized generation directly at the customers' premises, favoring self-consumption, can bring significant changes for distribution network operation. According to the new Portuguese law, injection of energy into the distribution grid is discouraged since prosumers receive only 90% of the energy cost in the Iberian Energy Market. In order to lower energy bills, the possibility of storing excess energy is being considered as a possible solution. In this paper, an optimization framework is proposed to model the operation of consumers with renewable-based Distributed Generation (DG) and storage capacity and assess their aggregated effect at the level of the MV grid using a multi-temporal Optimal Power Flow (OPF). The proposed algorithm is then tested in a real Portuguese MV network to evaluate its performance. Finally, a financial viability analysis is performed considering the installation of small PV generators and storage devices at the residential level.

A multi-temporal optimal power flow for managing storage and demand flexibility in LV networks

“…The equality constraints imposed by the power balance of each node of the network and for each period are shown in (10) and (11). Here, the indices of the hours and phases have been omitted for readability purposes only.…”

“…sin − cos As previously mentioned, the main feature of this algorithm is the integration of the storage unit(s) in the OPF algorithm, which originate the multi-period constraints related to the operation of the storage device(s) [10].…”

“…The limits for the SOC were also considered for each storage device as shown in (10) where , the upper limit, is the storage capacity of the storage device and , , the lower limit. The lower limit of the storage SOC is defined for each hour according to the required backup capacity that needs to be ensured for purposes of quality and continuity of service, namely considering the load forecasting for the next hour(s).…”

Assessing the impact of demand flexibility on distribution network operation

“…Several studies about the DER alternatives and impacts on the network operation have been conducted. Regarding storage devices (SD), in addition to analysis of the impacts on the network, there are comparison between diverse technologies [2], different formulations to determine the optimal operation depending on the entity owning the resources [3] and even studies about the aggregation between SD and distributed generation (DG) [4]. For electric vehicles (EV), not only exists frameworks to successfully integrate electric vehicles into electric power systems [5], but also studies about the potential economic implications of using vehicle batteries to grid storage devices [6].…”

“…The evaluation of the DER flexibility impact on the MV grid operation was performed using a multi-temporal Optimal Power Flow (OPF), described in section II. The algorithm, adapted from [4], was developed using an approach to minimize the distribution network operation cost, taking advantage of the DER flexibility, and maximize at the same time the integration of renewable energy. The implemented method seeks for an optimal solution through the resource utilization resulting on a lower cost over the selected periods, in a way that voltage and branches limits are always respected.…”