Microgrids have emerged as an alternative to alleviate increasing energy demands. However, because microgrids are primarily based on nonconventional energy sources (NCES), there is high uncertainty involved in their operation. The aim of this paper is to formulate a robust energy management system (EMS) for a microgrid that uses model predictive control theory as the mathematical framework. The robust EMS (REMS) is formulated using a fuzzy prediction interval model as the prediction model. This model allows us to represent both nonlinear dynamic behavior and uncertainty in the available energy from NCES. In particular, the uncertainty in wind-based energy sources can be represented. In this way, upper and lower boundaries for the trajectories of the available energy are obtained. These boundaries are used to derive a robust formulation of the EMS. The microgrid installed in Huatacondo was used as a test bench. The results indicated that, in comparison with a nonrobust approach, the proposed formulation adequately integrated the uncertainty into the EMS, increasing the robustness of the microgrid by using the diesel generator as spinning reserve. However, the operating costs were also slightly increased due to the additional reserves. This achievement indicates that the proposed REMS is an appropriate alternative for improving the robustness, against the wind power variations, in the operation of microgrids.

This paper summarizes the three-year technical activities of the IEEE Task Force (TF) on behind-the-meter (BTM) distributed energy resources (DERs): estimation, uncertainty quantification, and control. The potential grid services from BTM DERs are discussed in detail. The paper also reviews the state-of-the-art for BTM DERs visibility, uncertainty quantification, and, optimization and control. Furthermore, different aspects of the market structures associated with BTM DERs are covered, including emerging market and business models. Finally, needs and recommendations are provided for additional areas such as system protection, computing capabilities, algorithm development, market structure design, cyberinfrastructure and security, and hardware and software developments.

In the last few years, several investigations have been carried out in the field of optimal sizing of energy storage systems (ESSs) at both the transmission and distribution levels. Nevertheless, most of these works make important assumptions about key factors affecting ESS profitability such as efficiency and life cycles and especially about the specific costs of the ESS, without considering the uncertainty involved. In this context, this work aims to answer the question: what should be the costs of different ESS technologies in order to make a profit when considering peak shaving applications? The paper presents a comprehensive sensitivity analysis of the interaction between the profitability of an ESS project and some key parameters influencing the project performance. The proposed approach determines the break-even points for different ESSs considering a wide range of life cycles, efficiencies, energy prices, and power prices. To do this, an optimization algorithm for the sizing of ESSs is proposed from a distribution company perspective. From the results, it is possible to conclude that, depending on the values of round trip efficiency, life cycles, and power price, there are four battery energy storage systems (BESS) technologies that are already profitable when only peak shaving applications are considered: lead acid, NaS, ZnBr, and vanadium redox.

Power system stability is widely assessed based on tools that rely on the representation of voltages and currents through quasi-static phasor calculus, implying that the network itself and the synchronous machine stators are modeled by algebraic equations. Accordingly, the associated fast transients are ne-glected, assuming those decay rapidly. However, with the in-creasing penetration of converter interfaced generation in pow-er systems, the reliance on quasi-static phasor calculus is to be questioned. In this paper, the validity of quasi-static phasor calculus models is verified, and dynamic phasor calculus is considered as the alternative. A methodology to systematically compare quasi-static and dynamic phasor calculus is developed. It includes frequency response, modal, and sensitivi-ty analyses. The methodology is applied to an IEEE test net-work considering penetrations of converter interfaced genera-tion of up to 100 %. The models are implemented in MATLAB. The H-infinity norm is proposed as an indicator to identify differences in the applicability of the models. The results show that the quasi-static phasor calculus is suitable for stability analysis only if low bandwidths of converter controls are given. Dynamic phasor calculus instead is suitable and applicable to generic stability studies of integrated power electric and elec-tronic systems with high penetration of renewables.