Publicação
Community energy microgrids: the role of energy exchange between prosumers
| Resumo: | In the European Union, the current energy paradigm promotes the deployment and integration of renewables, particularly of the distributed kind, as a way to increase the share of clean energy in the global energy mix. Investments made in this sense have simultaneously been allowing and leading towards the integration of energy produced at the local level on the distribution grid. Recent price drops in small and micro scale energy generation systems have allowed residential consumers to invest in small scale units for self-production. Due to its low maintenance requirements and modularity, photovoltaic panels are the preferred choice when it comes to small energy generation. However, as solar energy alone cannot match all daily consumption needs, only by investments in energy storage units one can further decrease the dependency on the main grid. In this dissertation a second option is suggested – energy exchange between local prosumers in a smart microgrid. The hypothesis was studied through the simulation, in AIMMS software, of an energy system intended to reproduce a typical urban neighborhood, composed by six prosumers of different activity sectors and, hence, having different daily load profiles. Considering that at least some of those will have an energy surplus during a part of the day, the idea of a local energy market for trading such surplus is introduced. For the management of this virtual energy market, two models were proposed: a centralized management model, which is intended to simulate a microgrid controlled by a single entity holding access to all data regarding production and demand of the microgrid participants, and a decentralized management model, simulating a scenario where prosumers individually manage their energy trades. Both models were optimized with mixed integer linear programming for cost minimization and simulated for four day-types, with hourly time intervals: winter week- and weekend-days and summer week- and weekend-days. A base scenario with no energy exchange between the prosumers, only with the main grid, serves as a reference for comparison. The results were quantified in terms of self-consumed power and financial balance analyses. Finally, a contextualization for the Portuguese legislation regarding self-consumption was made, in order to determine if this case-study and corresponding results could be adequate for the national legal situation. The results show that very similar outcomes of self-consumption are obtained for both management approaches, with a maximum daily divergence of 2,3%. Considering the overall average for the daily self-consumption values obtained, the difference between the two models is below 1%. When comparing with the base scenario it was verified that, on average, an overall 10% increase in self-consumption is obtained for the micro-grid as a whole. Regarding the financial outcomes, the application of a local energy market for energy exchange between microgrid prosumers resulted in an energy surplus valorization of 135%, on average for the day types simulated, compared to the value stipulated by the Portuguese legislation for self-consumption units. As a logical consequence of this result, an average of 21,6% increase in overall revenues for the prosumers was verified, compared with the revenues in the base scenario. The highest increases on the revenues are verified in the winter week-day scenario, in particular for the office. On average, the individual costs’ reduction is 1,2%, mostly due to savings during the summer. An overall economic analysis on the expected electricity bill of each prosumer and for the microgrid as a whole, revealed that the local energy market can cause a bill reduction of 3,3% for the winter week, and 5,3% for the summer. It can be concluded that, when considering the whole microgrid, the overall economic benefits in terms of economic savings are not so relevant as the results obtained in terms of self-consumed energy, for this particular case-study, although a more profound economic evaluation would be interesting to fully acknowledge the impacts of the observed financial benefits on the overall implied investment. When analyzing the results under the Portuguese legal framework it was concluded that 3 of the production units were oversized in terms of resulting connection power. |
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| Autores principais: | Ildefonso, Maria Beatriz Piedade Moreira de Moura Ildefonso |
| Assunto: | Micro rede Energia renovável Autoconsumo Prosumer Mercado local de energia Teses de mestrado - 2018 |
| Ano: | 2018 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | In the European Union, the current energy paradigm promotes the deployment and integration of renewables, particularly of the distributed kind, as a way to increase the share of clean energy in the global energy mix. Investments made in this sense have simultaneously been allowing and leading towards the integration of energy produced at the local level on the distribution grid. Recent price drops in small and micro scale energy generation systems have allowed residential consumers to invest in small scale units for self-production. Due to its low maintenance requirements and modularity, photovoltaic panels are the preferred choice when it comes to small energy generation. However, as solar energy alone cannot match all daily consumption needs, only by investments in energy storage units one can further decrease the dependency on the main grid. In this dissertation a second option is suggested – energy exchange between local prosumers in a smart microgrid. The hypothesis was studied through the simulation, in AIMMS software, of an energy system intended to reproduce a typical urban neighborhood, composed by six prosumers of different activity sectors and, hence, having different daily load profiles. Considering that at least some of those will have an energy surplus during a part of the day, the idea of a local energy market for trading such surplus is introduced. For the management of this virtual energy market, two models were proposed: a centralized management model, which is intended to simulate a microgrid controlled by a single entity holding access to all data regarding production and demand of the microgrid participants, and a decentralized management model, simulating a scenario where prosumers individually manage their energy trades. Both models were optimized with mixed integer linear programming for cost minimization and simulated for four day-types, with hourly time intervals: winter week- and weekend-days and summer week- and weekend-days. A base scenario with no energy exchange between the prosumers, only with the main grid, serves as a reference for comparison. The results were quantified in terms of self-consumed power and financial balance analyses. Finally, a contextualization for the Portuguese legislation regarding self-consumption was made, in order to determine if this case-study and corresponding results could be adequate for the national legal situation. The results show that very similar outcomes of self-consumption are obtained for both management approaches, with a maximum daily divergence of 2,3%. Considering the overall average for the daily self-consumption values obtained, the difference between the two models is below 1%. When comparing with the base scenario it was verified that, on average, an overall 10% increase in self-consumption is obtained for the micro-grid as a whole. Regarding the financial outcomes, the application of a local energy market for energy exchange between microgrid prosumers resulted in an energy surplus valorization of 135%, on average for the day types simulated, compared to the value stipulated by the Portuguese legislation for self-consumption units. As a logical consequence of this result, an average of 21,6% increase in overall revenues for the prosumers was verified, compared with the revenues in the base scenario. The highest increases on the revenues are verified in the winter week-day scenario, in particular for the office. On average, the individual costs’ reduction is 1,2%, mostly due to savings during the summer. An overall economic analysis on the expected electricity bill of each prosumer and for the microgrid as a whole, revealed that the local energy market can cause a bill reduction of 3,3% for the winter week, and 5,3% for the summer. It can be concluded that, when considering the whole microgrid, the overall economic benefits in terms of economic savings are not so relevant as the results obtained in terms of self-consumed energy, for this particular case-study, although a more profound economic evaluation would be interesting to fully acknowledge the impacts of the observed financial benefits on the overall implied investment. When analyzing the results under the Portuguese legal framework it was concluded that 3 of the production units were oversized in terms of resulting connection power. |
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