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Publications

Publications by José Villar

2013

Spanish coal royal decree: An energy security measure

Authors
Diaz, CA; Villar, J; Campos, FA; Gonzalez, P; Webster, M;

Publication
International Conference on the European Energy Market, EEM

Abstract
National governments sometimes introduce policies that modify energy markets to achieve other social and political goals. These policies, created with the best of intentions, often have unintended consequences. Here we present a case study of one such policy, the Royal Decree in Spain that mandates the use of the Spanish-Indigenous Coal (IC). © 2013 IEEE.

2016

Combined penetration of wind and solar generation with plug-in electric vehicles

Authors
Villar, J; Salas, E; Alberto Campos, A;

Publication
ENERGY ECONOMICS IBERIAN CONFERENCE, EEIC 2016

Abstract
Combining large penetration of wind and solar generation with Plug-in Electric Vehicles (PEVs) seems a promising solution for energy cost saving and emissions reduction. PEVs connected to the grid with smart charging strategies can be an effective way to integrate non-dispatchable renewable generation, smoothing the load curve, contributing to the system stability by providing regulation services, and moving unhealthy emissions away from city centers. This paper analyzes the combined penetration of PEVs, and wind and solar generation using a Unit Commitment model for the Spanish power system, providing some insight on how the penetration of these technologies affects relevant variables such as energy and reserve, thermal plants behavior (such as starts-up and shut-downs, technological energy share, generation costs or emissions) and systems costs. Results show that PEV increase total demand, but its optimal charging smooths the net demand (to be supplied by thermal units) and the final electricity prices. In addition, solar generation penetration leads to a larger net demand with more variability but with lower production costs than wind generation penetration, due to their different hourly profiles. Finally neither solar nor wind generation penetrations are totally profitable for the system with the assumptions made, since their investments costs do not compensate the production cost decrement, but grid parity is almost reached for both technologies. (C) 2016 The Authors. Published by Elsevier Ltd.

2015

Bi-level optimization of electricity tariffs and PV distributed generation investments

Authors
Cervilla, C; Villar, J; Campos, FA;

Publication
International Conference on the European Energy Market, EEM

Abstract
Distributed Generation (DG) is providing end consumers the possibility to satisfy part of their electricity consumption by using their own small-scale power generators. To regulate DG, new regulation schemes are needed, being net metering one of the most used. However, regulators appreciate that net metering could jeopardize the incomes to cover the regulated activities' cost. This paper proposes a mathematical bi-level model to obtain the evolution of the access tariffs and their corresponding incomes needed to cover the regulated costs, as well as the optimal DG investment of the consumers under a net metering regulation, in a simplified framework. © 2015 IEEE.

2017

Endogenous secondary reserves requirements in long-term electricity generation models

Authors
Campos, FA; Domenech, S; Villar, J;

Publication
International Conference on the European Energy Market, EEM

Abstract
Secondary Reserve Requirements (SRR) are usually estimated based upon unit failure rates, and demand and intermittent productions forecasting errors. These requirements are very often inputs to energy and reserve generation dispatch models. However, for the long term, the fact that renewable generation investments must also be computed, affects these requirements. This paper proposes a new Unit Commitment (UC) to represent the SRR in long-term electricity generation models as a function of the renewable investment decisions. Specifically, SRRs are computed as a function of the forecasting errors of renewable productions, and of the unavailability rates of the generation units, which are also outputs of the UC. The case studies show that, when SRRs are endogenous, investments in renewable generation can be lower than expected due to the additional reserve costs these technologies involve. © 2017 IEEE.

2015

Optimal planning and operation of distributed energy resources considering uncertainty on EVs

Authors
Martin, F; Sanchez Miralles, A; Villar, J; Calvillo, CF; Soder, L;

Publication
2015 IEEE 1st International Smart Cities Conference, ISC2 2015

Abstract
Operation of distributed energy resources is taking importance nowadays. This paper proposes an optimal planning and operation model of distributed energy resources in a district taking into account the mobility of consumers using conventional fuel vehicles (FV) or electric vehicles (EV). The stochastic model considers the uncertainty of the type of vehicle, availability and distance traveled, and then it manages the available resources to obtain the maximum benefit from the grid. Results show that the EVs assist to achieve greater benefits of the distributed resources. Moreover, the costs per driven km are mainly independent of the type of vehicle considered. © 2015 IEEE.

2018

Advanced scoring method of eco-efficiency in European cities

Authors
Moutinho, V; Madaleno, M; Robaina, M; Villar, J;

Publication
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

Abstract
This paper analyzes a set of selected German and French cities' performance in terms of the relative behavior of their eco-efficiencies, computed as the ratio of their gross domestic product (GDP) over their CO2 emissions. For this analysis, eco-efficiency scores of the selected cities are computed using the data envelopment analysis (DEA) technique, taking the eco-efficiencies as outputs, and the inputs being the energy consumption, the population density, the labor productivity, the resource productivity, and the patents per inhabitant. Once DEA results are analyzed, the Malmquist productivity indexes (MPI) are used to assess the time evolution of the technical efficiency, technological efficiency, and productivity of the cities over the window periods 2000 to 2005 and 2005 to 2008. Some of the main conclusions are that (1) most of the analyzed cities seem to have suboptimal scales, being one of the causes of their inefficiency; (2) there is evidence that high GDP over CO2 emissions does not imply high eco-efficiency scores, meaning that DEA like approaches are useful to complement more simplistic ranking procedures, pointing out potential inefficiencies at the input levels; (3) efficiencies performed worse during the period 2000-2005 than during the period 2005-2008, suggesting the possibility of corrective actions taken during or at the end of the first period but impacting only on the second period, probably due to an increasing environmental awareness of policymakers and governors; and (4) MPI analysis shows a positive technological evolution of all cities, according to the general technological evolution of the reference cities, reflecting a generalized convergence of most cities to their technological frontier and therefore an evolution in the right direction.

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