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Publications

Publications by José Villar

2022

Integrating flexibility and energy local markets with wholesale balancing responsibilities in the context of renewable energy communities

Authors
Mello, J; Villar, J;

Publication
TECHNOLOGIES, MARKETS AND POLICIES: BRINGING TOGETHER ECONOMICS AND ENGINEERING

Abstract
Final consumers can be organized in collective self-consumption structures and energy communities to share and trade among them the energy they produce locally and can also be potential providers of flexibility services to the grid. However, the integration of local and wholesale electricity markets is still a matter of development, demanding innovative solutions that consider, among other things, the impact of the energy transfers from the activated flexibility on the balancing responsible parties' portfolio in the context of the wholesale settlement rules. This work proposes an innovative design for the integration of local energy markets and local flexibility markets based on the current collective selfconsumption regulation in Portugal. The main roles and contractual framework are defined and the energy transfer of activated flexibility between aggregators and retailers is tackled using regular LEM energy transfers.

2018

Synergies of electric urban transport systems and distributed energy resources in smart cities

Authors
Calvillo C.; Sanchez-Miralles A.; Villar J.;

Publication
IEEE Transactions on Intelligent Transportation Systems

Abstract
Transport systems and buildings are among the bigger energy users inside cities. Abundant research has been developed about these systems (facilities and transport). However, synergies among them are commonly overlooked, not taking advantage of the possible benefits of their joint coordination and management. This paper presents a linear programming model to find the optimal operation and planning of distributed energy resources (DER) in a residential district, while considering electric private and public transport systems, in particular electric vehicles and metro. Hence, the main contribution of this paper is the analysis of synergies of such an interconnected scheme. It has been assumed that part of the metro regenerative braking energy can be stored into electric vehicles' (EVs') batteries, so that it can be used later for other trains or for the EV itself. Several case studies have been proposed using data from a residential district and a metro line in Madrid. The obtained results show important cost savings in the overall system, especially a significant power cost reduction for the metro system.

2022

Concept and design of a Real Time Walrasian Local Electricity Market

Authors
Mello, J; Villar, J; Saraiva, JT;

Publication
International Conference on the European Energy Market, EEM

Abstract
This paper proposes a real time Walrasian based market design for local electricity trading, considering the roles of the different players, the settlement procedures, and the necessary balance responsibilities with the wholesale market under collective self-consumption rules. A Walrasian mechanism based on consecutive auctions for very short delivery periods is proposed, where the auctioneer defines a price for each of these delivery periods to which peers react by generating and consuming accordingly and informing if they trade with the auctioneer or with their retailer or aggregator. This market has no energy purchase contracts, and energy is billed based on each peer's generation or consumption for each delivery period with the price defined by the auctioneer. © 2022 IEEE.

2022

EUNIVERSAL'S SMART GRID SOLUTIONS FOR THE COORDINATED OPERATION & PLANNING OF MV AND LV NETWORKS WITH HIGH EV INTEGRATION

Authors
Sampaio G.; Gouveia C.; Bessa R.; Villar J.; Retorta F.; Carvalho L.; Merckx C.; Benothman F.; Promel F.; Panteli M.; Mourão R.L.; Louro M.; Águas A.; Marques P.;

Publication
IET Conference Proceedings

Abstract
EUniversal project aims to facilitate the use of flexibility services and interlink distribution system's active management with electricity markets. Implementing market-based flexibility services implies a change in distribution network monitoring and control towards a more predictive approach. However, integrating cost-effective monitoring and control tools for the LV network is still quite challenging. Within the project, a set of operation and planning tools have been developed for a coordinated quantification and activation of flexibility in HV, MV and LV distribution networks. The paper presents the tools developed for the Portuguese pilot and shows preliminary results obtained when considering network operation scenarios characterized by large scale integration of DER and EV.

2022

Grid flexibility services from local energy markets: a three-stage model

Authors
Rocha, R; Retorta, F; Mello, J; Silva, R; Gouveia, C; Villar, J;

Publication
TECHNOLOGIES, MARKETS AND POLICIES: BRINGING TOGETHER ECONOMICS AND ENGINEERING

Abstract
This paper proposes an energy community management system for local energy sharing with grid flexibility services to solve the potential grid constraints of the local distribution network. A three-stage model is proposed. Stage 1 is the individual minimization of the energy bill of each prosumer by optimizing the schedules of its battery. The second stage optimizes the energy bill of the energy community by sharing internally the prosumers energy surplus and re-dispatching their batteries, while guaranteeing that each new individual prosumer energy bill is always equal or less than its stage 1 bill. The third stage is performed by the DSO to solve the grid constraints by re-dispatching the batteries, curtailing local generation or reducing consumption. Stage 3 minimizes the impact on stage 2 by minimizing the loss of profit or utility of every prosumer which is compensated accordingly.

2022

Maximizing Green Hydrogen Production with Power Flow Tracing

Authors
Dudkina, E; Villar, J; Bessa, RJ;

Publication
International Conference on the European Energy Market, EEM

Abstract
Decarbonization of energy systems is one of the main tracks in the energy sector, and in this transition, green hydrogen assumes an important role. Considering the variability of renewable energy sources (RES), the flexibility of the hydrogen production could help dealing with imbalances. However, to truly contribute to a greener energy mix, a principle of additivity must be obeyed. In other words, to produce green hydrogen, the energy supplied to the electrolyzers must be renewable and must not entail a decrease in the RES consumed by other loads according to the energy strategic plans. This study integrates power flow tracing (PFT) technique within an optimal power flow (OPF) to determine and maximize the physical flow between the energy from RES generators and the electrolyzer through the existing grid. The proposed method was tested on both radial and meshed IEEE test grids. Simulation results showed that the electrolyzer green supply can be increased by controlling the dispatch of the distributed generators (e.g., CHP) according to the location of the electrolyzer. In addition, installing storage systems nearby load buses allows increasing the amount of green supply by using the RES-based electricity stored. © 2022 IEEE.

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