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- Optimizing the performance of renewable sources using virtual renewable power plantsPublication . Rodrigues, L.; Estanqueiro, AnaThe concept of “Virtual Renewable Power Plants - VRPP” enables several positive factors for the electric integration of Renewable Energy Sources (RES) and enables the optimization of its technical and economic performance by using the natural complementary of renewable resources availability. Moreover, the establishment of synergies between different RES contributes for the smoothing of time based fluctuation of the power delivered by the RES. The present work aims to identify the synergies between wind and photovoltaic (PV) plants, regarding their daily profiles complementarity and resource availability; as well as the technical and economic added value of a VRPP. Results show an increase of 5.3% in the capacity factor and 25% in the revenue when 2 MWp of PV are added to an 8 MW wind farm, and a potential benefit of 48% when adding a storage system of 2 MW (8 MWh), considering all infrastructural capacity limits. Moreover, the combined VRPP daily production profiles have a significantly higher correlation with the average daily load profile (0.82) than WTG (0.41) or PV (0.54) alone.
- Report 2023 : PortugalPublication . Couto, António; Simões, Teresa; Costa, Paula Silva; Estanqueiro, AnaABSTRACT: In 2023, the new installed wind power capacity amounted to 159 MW. This capacity refers to overcapacity procedures, building on existing sites. Important milestones were attained by the ministerial working group created by the Portuguese government to accelerate the offshore wind market, expecting a total installed capacity of 10 GW.
- Cooperação entre o consumidor final e o agregador na gestão do consumoPublication . Osório, José; Assis, M.; Estanqueiro, AnaRESUMO: Esta interação agregador/consumidor final, baseada em escolhas racionais vantajosas para ambos, leva o consumidor a valorizar (e ver valorizada) a flexibilidade que é capaz de oferecer. O consumidor agenda o consumo como prefere, bem como alternativas que aceita, e se quiser, o ganho diferencial mínimo que exige, na sua fatura de eletricidade, para alguma(s) dessas colocações alternativas. Deve também definir a prioridade que atribui a cada consumo sob a forma do preço máximo que está disposto a por ele pagar. Com estes dados pode-se otimizar a fatura, sendo importante visar-se o ganho líquido, i.e., deduzido dos ganhos diferenciais que o consumidor possa ter exigido. A agenda de consumos é então ajustada à produção renovável local e ao preço horário do mercado. A complexidade da procura exige heurísticas e as simulações em MATLAB encorajam um apuramento das metodologias usadas e até alguma sofisticação adicional em termos das alternativas de escolha disponibilizáveis ao consumidor e ao agregador. Esta ferramenta pode ajudar o agregador a conciliar interesses em pequenos mercados e em comunidades de energia.
- Caraterização do recurso renovável offshore para o planeamento da instalação de sistemas de energias renováveis marinhas na costa portuguesaPublication . Simões, Teresa; Couto, António; Justino, Paulo Alexandre; Estanqueiro, AnaRESUMO: As energias renováveis marinhas (Offshore) apresentam um grande potencial de exploração em Portugal, por um lado devido à situação geográfica do país, com a sua área extensa de costa e uma das maiores zonas económicas exclusivas – e por outro, pelos indicadores de existência de elevado recurso energético, cujo estudo tem vindo a ser efetuado nos últimos anos. Não obstante esses estudos, persistem várias barreiras a ultrapassar para a disseminação das tecnologias de energias renováveis com maior aplicabilidade em Portugal – eólica offshore e ondas. Neste contexto, surgiu o projeto OffshorePlan - Planeamento da instalação de energias renováveis offshore em Portugal, no qual se desenvolveu uma metodologia de planeamento da instalação de sistemas de energias renováveis offshore – eólica offshore e ondas – onde se inclui o refinamento e a validação dos mapeamentos do potencial eólico e das ondas existentes. Neste trabalho apresentam-se as metodologias desenvolvidas para o mapeamento do recurso eólico offshore e das ondas, e a sua validação com dados experimentais obtidos com base em sensores LiDAR e bóias hidrográficas. Os resultados constituem atualmente os Atlas do potencial eólico offshore e de energia das ondas em Portugal.
- Impacts of large amounts of wind power on design and operation of power systems, results of IEA collaborationPublication . Holttinen, Hannele; Meibom, Peter; Orths, Antje; Lange, Bernhard; O'Malley, Mark; Tande, John O.; Estanqueiro, Ana; Gomez, Emilio; Soder, Lennart; Strabac, Goran; Smith, J. Charles; Van Hulle, FransThere are dozens of studies made and ongoing related to wind integration. However, the results are not easy to compare. IEA WIND R&D Task 25 on ‘Design and Operation of Power Systems with Large Amounts of Wind Power’ collects and shares information on wind generation impacts on power systems, with analyses and guidelines on methodologies. In the state-of-the-art report (October, 2007), and the fi nal report of the 3 years period (July, 2009) the most relevant wind power grid integration studies have been analysed especially regarding methodologies and input data. Several issues that impact on the amount of wind power that can be integrated have been identifi ed. Large balancing areas and aggregation benefi ts of wide areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and functioning electricity markets at less than day-ahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefi ts, electricity markets and larger balancing areas. Best practices in wind integration studies are described. There is also benefi t when adding wind power to power systems: it reduces the total operating costs and emissions as wind replaces fossil fuels and this should be highlighted more in future studies.
- Modelling machine interaction in a wind park with regard to stability and regulation: present status of NATO SfS Po-MISTRALPublication . Castro, Rui; Estanqueiro, Ana; Saraiva, J. A. Gil; Gomes, Luís; Jesus, J.M. Ferreira
- Energy storage for wind integration: hydropower and other contributionsPublication . Estanqueiro, Ana; Ardal, Atle Rygg; O'Dwyer, Ciara; Flynn, Damian; Huertas-Hernando, Daniel; Lew, Debra; Gomez-Lázaro, E.; Ela, Erik; Revuelta, Javier; Kiviluoma, Juha; Rodrigues, L.; Amelin, Mikael; Holttinen, HanneleThe amount of wind power and other timevariable non-dispatchable renewable energy sources (RES) is rapidly increasing in the world. A few power systems are already facing very high penetrations from variable renewables which can surpass the systems’ consumption during no-load periods, requiring the energy excess to be curtailed, exported or stored. The limitations of electric energy storage naturally lead to the selection of the well-known form of storing potential energy in reservoirs of reversible hydropower stations, although other technologies such as heat storage are also being used successfully. This paper reviews the storage technologies that are available and may be used on a power system scale and compares their advantages and disadvantages for the integration of fast-growing renewables, such as wind power, with a special focus on the role of pumped hydro storage.
- A multistage stochastic approach for the optimal bidding of variable renewable energy in the day-ahead, intraday and balancing marketsPublication . Silva, Ana Rita; Pousinho, H. M. I.; Estanqueiro, AnaABSTRACT: Market agents with renewable resources face amplified uncertainty when forecasting energy production to securely place bids in electricity markets. To deal with uncertainties, stochastic modelling has been applied to optimize the bidding strategy of these market agents. However, studies found in the literature usually focus on day-ahead and balancing markets, leaving aside intraday markets that could be used to correct bidding positions as uncertainty gets resolved. This paper proposes a multistage stochastic decision-aid algorithm based on linear programming to optimize the bidding strategy of market agents in three different electricity markets -day-ahead, intraday, and balance markets. The market agent represents a Virtual Power Plant with wind, solar PV, and storage technologies, and its participation in three electricity markets was compared to the participation in DA and BM markets only. Results show that participating in all three markets increased the profit achieved by the VPP agent by 10.1% while also decreasing the incurred imbalances by 63.8%. The results demonstrate that having accurate tools to deal with the multi-settlement framework of electricity markets while considering the uncertainties of daily operations is key to a successful integration of renewable energy resources into electricity markets and power systems.
- PV systems linked to the grid: parameter identification with a heuristic procedurePublication . Fialho, L.; Melício, R.; Mendes, V. M. F.; Estanqueiro, Ana; Pereira, Manuel CollaresThis paper focuses on a PV system linked to the electric grid by power electronic converters, identification of the five parameters modeling for photovoltaic systems and the assessment of the shading effect. Normally, the technical information for photovoltaic panels is too restricted to identify the five parameters. An undemanding heuristic method is used to find the five parameters for photovoltaic systems, requiring only the open circuit, maximum power, and short circuit data. The I–V and the P–V curves for a monocrystalline, polycrystalline and amorphous photovoltaic systems are computed from the parameters identification and validated by comparison with experimental ones. Also, the I–V and the P–V curves under the effect of partial shading are obtained from those parameters. The modeling for the converters emulates the association of a DC–DC boost with a two-level power inverter in order to follow the performance of a testing commercial inverter employed on an experimental system.
- Impact of weather conditions on the windows of opportunity for operation of offshore wind farms in portugalPublication . Silva, N.; Estanqueiro, AnaThe deployment of offshore wind parks face several challenges. Among them are the difficulties introduced by the atmospheric and sea conditions in accessing those wind parks. A window of opportunity is a timeframe when weather and sea conditions are acceptable and enable to perform specific tasks in the installation and operation/maintenance of the offshore wind park. This study identifies typical time periods of windows of opportunity to access three offshore Portuguese maritime regions. The accessibility conditions also take into account the system type transportation method for local access, namely, rubber boat, boat with OAS or helicopter. It was concluded that Portugal has adequate conditions for offshore site maintenance strategies, with a large number of windows of opportunity, but they are relatively short, therefore the installation of offshore wind parks must be carefully planned. This is an important factor in favor of the offshore wind farm deployments on the country.