Abstract
In order to reduce the curtailment of renewable generation in periods of low load, operators can limit the import net transfer capacity (NTC) of interconnections. This paper presents a probabilistic approach to support the operator in setting the maximum import NTC value in a way that the risk of curtailment remains below a pre-specified threshold. Main inputs are the probabilistic forecasts of wind power and solar PV generation, and special care is taken regarding the tails of the global margin distribution (all generation all loads and pumping), since the accepted thresholds are generally very low. Two techniques are used for this purpose: interpolation with exponential functions and nonparametric estimation of extreme conditional quantiles using extreme value theory. The methodology is applied to five representative days, where situations ranging from high maximum NTC values to NTC=0 are addressed. Comparison of the two techniques for modeling tails is also comprised.

Abstract
This paper addresses the problem of decision making in Unit Commitment in systems with a significant penetration of wind power. Traditional approaches to Unit Commitment are inadequate to fully deal with the uncertainties associated to wind, represented by scenarios of forecasted wind power qualified by probabilities. Departing from a critique of planning paradigms, the paper argues that a stochastic programming approach, while a step in the good direction, is insufficient to model all aspects of the decision process and therefore proposes the adoption of models based on a Risk Analysis paradigm. A case study is worked out reinforcing this perspective. In a multi-objective context, the properties of the cost vs. risk Pareto-optimal fronts are analyzed, where risk may be represented by aversion to a worst scenario or a worst event. It is shown that the Pareto-optimal front may not be convex, which precludes a simplistic use of tradeoff concepts. It is also shown that decisions based on stochastic programming may in fact put the system at risk. An evaluation of risk levels and cost of hedging against undesired events is proposed as the paradigm to be followed in Unit Commitment decision making. (C) 2016 Published by Elsevier Ltd.

Abstract
The increase of demand side participation in reserve service (RS) requires the extension of the markets' activity to the millions of consumers present in the residential sector. This paper proposes a method that performs a bottom-up aggregation of residential demand-side flexibility associated with domestic appliances, namely Thermostatically Controlled Loads (TCL). The flexibility profiles provided by each residential consumer are transformed into aggregated reserve bids to be offered in the day ahead tertiary reserve markets. A case study involving 1500 end-users associated with an aggregator bidding in the Portuguese tertiary reserve market will be used to illustrate the method. (C) 2016 Published by Elsevier B.V.

Abstract
The integration of wind power in electricity generation brings new challenges to the unit commitment problem, as a result of the random nature of the wind speed. The scheduling of thermal generation units at the day-ahead stage is usually based on wind power forecasts. Due to technical limitations of thermal units, deviations from those forecasts during intra-day operations may lead to unwanted consequences, such as load shedding and increased operating costs. Wind power forecasting uncertainty has been handled in practice by means of conservative stochastic scenario-based optimization models, or through additional operating reserve settings. However, generation companies may have different attitudes towards the risks associated to wind power variability. In this paper, operating costs and load shedding are modeled by non-linear utility functions aggregated into a single additive utility function of a multi-objective model. Computational experiments have been done to validate the approach: firstly we test our model for the wind-thermal unit commitment problem and, in a second stage, pumped storage hydro units are added, leading to a model with wind-hydro-thermal coordination. Results have shown that the proposed methodology is able to correctly reflect different risk profiles of decision makers for both models.

Abstract
This paper evaluates the flexibility provided by distributed energy resources (DER) in a real electricity distribution network in Germany. Using the Interval Constrained Power Flow (ICPF) tool, the maximum range of flexibility available at the primary substation was obtained for different operation scenarios. Three test cases were simulated, differing mainly in the considered level of renewable energy sources (RES) production. For each test case, the obtained results enabled the construction of flexibility areas that define, for a given operating point, the limits of feasible values for the active and reactive power that can be exchanged between the TSO and the DSO. Furthermore, the tool can also be used to evaluate the contribution from each type of DER to the overall distribution network flexibility.

Abstract
The emergence of the smart grid concept led to different proposals for the organization of distributed energy resources (DER), control processes, and management functionalities, instantiated in distinct architectures. Besides the usual scientific publications about the theme, a number of projects, namely, in the Framework Programs FP6 and FP7 and Horizon 2020 (H2020) of the European Union, have been developed in the recent years, addressing this theme directly and indirectly. Commercial solutions are already available for total or partial implementation of smart grids, namely, regarding network automation and enhanced network operation smart appliances. On the other hand, some pilots and demonstration projects that field-tested architectures and functionalities and assessed the impact of the changes in the electric power systems derived from the implementation of smart grid concepts have been deployed throughout the world. This chapter reviews the most relevant elements of this kind, compares the main options for the overall architectures, and details the analysis of some specific functionalities, indispensable for the real implementation of the smart grid paradigm. © 2016 John Wiley & Sons, Ltd. All rights reserved.