Browsing by Author "Rodriguez, Rafael"

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    Flexible load management using flexibility bands
    (2022) Saavedra, Aldo; Negrete-Pincetic, Matias; Rodriguez, Rafael; Salgado, Marcelo; Lorca, Alvaro
    The large integration of variable renewable energy sources brings new challenges to system operations due to their volatile nature. In this context, demand response programs appear as an important alternative to match the instantaneous supply and demand of energy by changing the electric use of end-users. The traditional load control schemes of demand response are the direct and indirect control. While the direct schemes assure coordination and fail in scalability, the indirect schemes assure scalability, but they could fail in coordination. To face some of the challenges, this paper defines a framework and mathematical formulation for the interactions between a demand aggregator and its end-users, based on flexibility bands. It allows the aggregator to communicate and control a higher number of end-users at the same time that the end-users can make local decisions regarding their consumption. The flexibility band is a control signal, composed of an upper and a lower consumption bound, so that end consumers can consume electricity in the way they want as long as they stay within these bounds. The band features can be linked to contractual arrangements allowing the creation of new products for electricity markets. The simulations consider an aggregator interacting with 10000 end-users. The end-users present different types of flexible loads, such as thermal, deferrable, and non interruptible loads. The results indicate that this scheme is capable of achieving scalability and coordination, and it has the potential to provide new services such as adjusting the flexibility bands after the first response from end-users.
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    The value of aggregators in local electricity markets: A game theory based comparative analysis
    (2021) Rodriguez, Rafael; Negrete-Pincetic, Matias; Figueroa, Nicolas; Lorca, Alvaro; Olivares, Daniel
    Demand aggregators are expected to have a key role in future electricity systems. More specifically, aggregators can facilitate the harnessing of consumers' flexibility. This paper focuses on understanding the value of the aggregator in terms of aggregation of both flexibility and information. We consider the aggregation of flexibility as the ability to exercise a direct control over loads, while the aggregation of information refers to knowledge of the flexibility characteristics of the consumers. Several game theory formulations are used to model the interaction between the energy provider, consumers and the aggregator, each with a different information structure. We develop a potential game to obtain the Nash equilibrium of the non-cooperative game with complete information and we analyze the system dynamics of consumers using the adaptive expectations method in an incomplete information scenario. Several key insights about the value of aggregators are found. In particular, the value of the aggregator is mainly related to the aggregation of information rather than flexibility, and flexibility is valuable only when it can be coordinated. In this sense, prices are not enough to guarantee an effective coordination. (C) 2021 Elsevier Ltd. All rights reserved.