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Publications

Publications by Alexandre Lucas

2021

Blockchain Technology Applied to Energy Demand Response Service Tracking and Data Sharing

Authors
Lucas, A; Geneiatakis, D; Soupionis, Y; Nai-Fovino, I; Kotsakis, E;

Publication
Energies

Abstract
Demand response (DR) services have the potential to enable large penetration of renewable energy by adjusting load consumption, thus providing balancing support to the grid. The success of such load flexibility provided by industry, communities, or prosumers and its integration in electricity markets, will depend on a redesign and adaptation of the current interactions between participants. New challenges are, however, bound to appear with the large scale contribution of smaller assets to flexibility, including, among others, the dispatch coordination, the validation of delivery of the DR provision, and the corresponding settlement of contracts, while assuring secured data access among interested parties. In this study we applied distributed ledger (DLT)/blockchain technology to securely track DR provision, focusing on the validation aspect, assuring data integrity, origin, fast registry, and sharing within a permissioned system, between all relevant parties (including transmission system operators (TSOs), aggregators, distribution system operators (DSOs), balance responsible parties (BRP), and prosumers). We propose a framework for DR registry and implemented it as a proof of concept on Hyperledger Fabric, using real assets in a laboratory environment, in order to study its feasibility and performance. The lab set up includes a 450 kW energy storage system, scheduled to provide DR services, upon a system operator request and the corresponding validations and verifications are done, followed by the publication on a blockchain. Results show the end to end execution time remained below 1 s, when below 32 requests/sec. The smart contract memory utilization did not surpass 1% for both active and passive nodes and the peer CPU utilization, remained below 5% in all cases simulated (3, 10, and 28 nodes). Smart Contract CPU utilization remained stable, below 1% in all cases. The performance of the implementation showed scalable results, which enables real world adoption of DLT in supporting the development of flexibility markets, with the advantages of blockchain technology.

2022

CROSS-BORDER FLEXIBILITY PREQUALIFICATION OF DER AND EVS BASED ON DECENTRALISED COMMUNICATION MECHANISMS FOR THE DISTRIBUTION SYSTEM OPERATION

Authors
Cruz, J; Silva, C; Louro, M; Cardoso, S; Gomes, E; Lucas, A; Silva, F; Alonso, B; Pestana, R; Glória, G; Saragoça, J; Egorov, A;

Publication
IET Conference Proceedings

Abstract
The adoption of battery-powered electric vehicles in the EU is expected to grow to 30-40 million by 2030. This, together with the large adoption of other Distributed Energy Resources (DERs), represents a great challenge for Distribution System Operators (DSOs) in multiple perspectives, such as providing the needed charging infrastructure and ensuring that everyone is served with the expected Quality of Service (QoS), by having a secure and reliable system operation capable of mitigating grid congestion and voltage violation events. One of the mechanisms to mitigate these events can be the usage of these DER, such as Electric Vehicles (EVs), as flexibility sources for the improvement of the planning and operation of power distribution systems. This paper proposes harmonising the coordination of the prequalification process for flexibility provision (product and grid prequalification) among System and Market Operators from Portugal, Spain and France, enabling the participation of flexibility providers in multiple markets from cross-border countries through a harmonised and non-redundant prequalification process. © 2022 CIRED workshop on E-mobility and power distribution systems. All rights reserved.

2012

Life cycle analysis of energy supply infrastructure for conventional and electric vehicles

Authors
Lucas, A; Silva, CA; Costa Neto, RC;

Publication
ENERGY POLICY

Abstract
Electric drive vehicle technologies are being considered as possible solutions to mitigate environmental problems and fossil fuels dependence. Several studies have used life cycle analysis technique, to assess energy use and CO2 emissions, addressing fuels Well-to-Wheel life cycle or vehicle's materials Cradle-to-Grave. However, none has considered the required infrastructures for fuel supply. This study presents a methodology to evaluate energy use and CO2 emissions from construction, maintenance and decommissioning of support infrastructures for electricity and fossil fuel supply of vehicles applied to Portugal case study. Using Global Warming Potential and Cumulative Energy Demand, three light-duty vehicle technologies were considered: Gasoline, Diesel and Electric. For fossil fuels, the extraction well, platform, refinery and refuelling stations were considered. For the Electric Vehicle, the Portuguese 2010 electric mix, grid and the foreseen charging point's network were studied. Obtained values were 0.6-1.5 gCO(2eq)/km and 0.03-0.07 MJ(eq)/km for gasoline, 0.6-1.6 gCO(2eq)/km and 0.02-0.06 MJ(eq)/km for diesel, 3.7-8.5 gCO(2eq)/km and 0.06-0.17 MJ(eq)/km for EV. Monte Carlo technique was used for uncertainty analysis. We concluded that EV supply infrastructures are more carbon and energetic intensive. Contribution in overall vehicle LCA does not exceed 8%.

2012

Impact of energy supply infrastructure in life cycle analysis of hydrogen and electric systems applied to the Portuguese transportation sector

Authors
Lucas, A; Costa Neto, RC; Silva, CA;

Publication
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

Abstract
Hydrogen and electric vehicle technologies are being considered as possible solutions to mitigate environmental burdens and fossil fuel dependency. Life cycle analysis (LCA) of energy use and emissions has been used with alternative vehicle technologies to assess the Well-to-Wheel (WTW) fuel cycle or the Cradle-to-Grave (CTG) cycle of a vehicle's materials. Fuel infrastructures, however, have thus far been neglected. This study presents an approach to evaluate energy use and CO2 emissions associated with the construction, maintenance and decommissioning of energy supply infrastructures using the Portuguese transportation system as a case study. Five light-duty vehicle technologies are considered: conventional gasoline and diesel (ICE), pure electric (EV), fuel cell hybrid (FCHEV) and fuel cell plug-in hybrid (FC-PHEV). With regard to hydrogen supply, two pathways are analysed: centralised steam methane reforming (SMR) and on-site electrolysis conversion. Fast, normal and home options are considered for electric chargers. We conclude that energy supply infrastructures for FC vehicles are the most intensive with 0.03-0.53 MJ(eq)/MJ emitting 0.7-27.3 g CO2eq/MJ of final fuel. While fossil fuel infrastructures may be considered negligible (presenting values below 2.5%), alternative technologies are not negligible when their overall LCA contribution is considered. EV and FCHEV using electrolysis report the highest infrastructure impact from emissions with approximately 8.4% and 8.3%, respectively. Overall contributions including uncertainty do not go beyond 12%. Copyright

2013

Vehicle to Grid Decentralized Dispatch Control Using Consensus Algorithm with Constraints

Authors
Lucas, A; Chang, S;

Publication
Smart Grid and Renewable Energy

Abstract

2015

Grid harmonic impact of multiple electric vehicle fast charging

Authors
Lucas A.; Bonavitacola F.; Kotsakis E.; Fulli G.;

Publication
Electric Power Systems Research

Abstract
Fast charging is perceived by users as a preferred method for extending the average daily mobility of electric vehicles (EV). The rated power of fast chargers, their expected operation during peak hours, and clustering in designated stations, raise significant concerns. On one hand it raises concerns about standard requirements for power quality, especially harmonic distortion due to the use of power electronics connecting to high loads, typically ranging from 18 to 24 kW h. On the other hand, infrastructure dimensioning and design limitations for those investing in such facilities need to be considered. Four sets of measurements were performed during the complete charging cycle of an EV, and individual harmonic's amplitude and phase angles behaviour were analysed. In addition, the voltage and current total harmonic distortion (THD) and Total Demand Distortion (TDD) were calculated and the results compared with the IEEE519, IEC 61000/EN50160 standards. Additionally, two vehicles being fast charged while connected to the same feeder were simulated and an analysis was carried out on how the harmonic phase angles would relate. The study concluded that the use of TDD was a better indicator than THD, since the former uses the maximum current (IL) and the latter uses the fundamental current, sometimes misleading conclusions, hence it is suggested it should be included in IEC/EN standard updates. Voltage THD and TDD for the charger analysed, were within the standard's limits of 1.2% and 12% respectively, however individual harmonics (11th and 13th) failed to comply with the 5.5% limit in IEEE 519 (5% and 3% respectively in IEC61000). Phase angles tended to have preferential range differences from the fundamental wave. It was found that the average difference between the same harmonic order phase angles was lower than 90°, meaning that when more than one vehicle is connected to the same feeder the amplitudes will add. Since the limits are dependable on the upstream short circuit current (ISC), if the number of vehicles increases (i.e. IL), the standard limits will decrease and eventually be exceeded. The harmonic limitation is hence the primary binding condition, certainly before the power limitation. The initial limit to the number of chargers is not the power capacity of the upstream power circuit but the harmonic limits for electricity pollution.

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