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Publications

Publications by CPES

2022

Renewable Energy Community Pairing Methodology Using Statistical Learning Applied to Georeferenced Energy Profiles

Authors
Lucas, A; Carvalhosa, S;

Publication
ENERGIES

Abstract
Renewable energy communities (REC) are bound to play a crucial role in the energy transition, as their role, activities, and legal forms become clearer, and their dissemination becomes larger. Even though their mass grid integration, is regarded with high expectations, their diffusion, however, has not been an easy task. Its legal form and success, entail responsibilities, prospects, trust, and synergies to be explored between its members, whose collective dynamics should aim for optimal operation. In this regard, the pairing methodology of potential participants ahead of asset dimensioning seems to have been overlooked. This article presents a methodology for pairing consumers, based on their georeferenced load consumptions. A case study in an area of Porto (Asprela) was used to test the methodology. QGIS is used as a geo-representation tool and its PlanHeat plugin for district characterization support. A supervised statistical learning approach is used to identify the feature importance of an overall district energy consumption profile. With the main variables identified, the methodology applies standard K-means and Dynamic Time Warping clustering, from which, users from different clusters should be paired to explore PV as the main generation asset. To validate the assumption that this complementarity of load diagrams could decrease the total surplus of a typical PV generation, 18 pairings were tested. Results show that, even though it is not true that all pairings from different clusters lead to lower surplus, on average, this seems to be the trend. From the sample analyzed a maximum of 36% and an average of 12% less PV surplus generation is observed.

2022

Demand Response Impact Evaluation: A Review of Methods for Estimating the Customer Baseline Load

Authors
Valentini, O; Andreadou, N; Bertoldi, P; Lucas, A; Saviuc, I; Kotsakis, E;

Publication
ENERGIES

Abstract
Climate neutrality is one of the greatest challenges of our century, and a decarbonised energy system is a key step towards this goal. To this end, the electricity system is expected to become more interconnected, digitalised, and flexible by engaging consumers both through microgeneration and through demand side flexibility. A successful use of these flexibility tools depends widely on the evaluation of their effects, hence the definition of methods to assess and evaluate them is essential for their implementation. In order to enable a reliable assessment of the benefits from participating in demand response, it is necessary to define a reference value (baseline) to allow for a fair comparison. Different methodologies have been investigated, developed, and adopted for estimating the customer baseline load. The article presents a structured overview of methods for the estimating the customer baseline load, based on a review of academic literature, existing standardisation efforts, and lessons from use cases. In particular, the article describes and focuses on the different baseline methods applied in some European H2020 projects, showing the results achieved in terms of measurement accuracy and costs in real test cases. The most suitable methodology choice among the several available depends on many factors. Some of them can be the function of the Demand Response (DR) service in the system, the broader regulatory framework for DR participation in wholesale markets, or the DR providers characteristics, and this list is not exclusive. The evaluation shows that the baseline methodology choice presents a trade-off among complexity, accuracy, and cost.

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.

2022

Tweet2Story: A Web App to Extract Narratives from Twitter

Authors
Campos, V; Campos, R; Mota, P; Jorge, A;

Publication
ADVANCES IN INFORMATION RETRIEVAL, PT II

Abstract
Social media platforms are used to discuss current events with very complex narratives that become difficult to understand. In this work, we introduce Tweet2Story, a web app to automatically extract narratives from small texts such as tweets and describe them through annotations. By doing this, we aim to mitigate the difficulties existing on creating narratives and give a step towards deeply understanding the actors and their corresponding relations found in a text. We build the web app to be modular and easy-to-use, which allows it to easily incorporate new techniques as they keep getting developed.

2022

Ester-based Dielectric Fluid for Power Transformers: Design and Test Experience under the GreenEst Project

Authors
Carvalhosa, S; Leite, H; Soares, M; Branco, F; Sá, CA; Lopes, RC; Santo, JE;

Publication
Journal of Physics: Conference Series

Abstract
Ester-based dielectric fluids have now been on the market for several decades, providing fire-safe and environmentally friendly alternatives to mineral oils, which have traditionally been used in transformers and other electrical equipment. This opens the door to innovation in power transformers. However, the use of esters-based dielectrics in power transformers is still very limited, especially for the higher voltage levels. The usage of these esters-based dielectrics in higher voltage power transformers is not yet consensual. this work present results with the use of natural esters in power distribution transformers. Tests carried out on mineral oil and natural ester oil found that the ester-based dielectric can withstand higher voltage thresholds for AC and Impulses tests, mainly within the specs of destructive tests, e.g., the natural ester was able to withstand a 185kV impulse without registering dielectric rupture while the natural oil registered a dielectric rupture with a 160kV impulse. Heating and mechanical tests demonstrated that ester-based dielectric oils for power transformers lead to a flow reduction between 16,8% and 18,2% in the cooling system that was design for mineral oils but they achieve a higher heat transfer coefficient, between 0,5% to 5% depending on the location of measurement. © Published under licence by IOP Publishing Ltd.

2022

A systematic review of environmental intervention studies in offices with beneficial effects on workers? health, well-being and productivity

Authors
Felgueiras, F; Cunha, L; Mourao, Z; Moreira, A; Gabriel, MF;

Publication
ATMOSPHERIC POLLUTION RESEARCH

Abstract
An increased risk of developing stress, musculoskeletal and cardiovascular diseases, rhinitis, skin and eye irri-tations and headaches has been particularly reported among office workers. Some of these complaints have been linked to the existence of poor indoor environmental quality (IEQ) in the workplaces. In this context, inter-vention studies can offer new insights to tackle poor IEQ issues and to identify effective measures to reduce IEQ-related risks. This review summarizes the main characteristics of environmental intervention studies that have been performed in office settings and the respective findings on the beneficial effects on the promotion of health, well-being, comfort, and productivity among office workers. The study design followed PRISMA guidelines and the search for peer-review articles was conducted in Scopus, Web of Science, PubMed, and Cochrane Library databases. Firstly, 513 records were identified, resulting in 23 articles included in the review after the application of the study eligibility criteria and identification of additional important works within the subject. The revised experimental studies were mainly focused on changes in ventilation systems via replacement of air filters and modifications in the rate of outdoor air supplied or temperature set-points. Some studies also included in-terventions based on the implementation of air cleaning and biophilic strategies. Both objective (e.g., physio-logical examinations) and subjective (e.g., questionnaires) measures have been used to assess the effects on office workers' outcomes. Overall, the findings presented here confirm that interventions aiming at improving IEQ in offices can be effective in improving health, well-being and productivity among office workers.

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