João Carlos Agrela

Abstract
The increasing integration of renewable energy sources and decentralized generation requires demand-side flexibility to improve grid stability and balance local energy flows. Local Flexibility Markets (LFMs) provide a framework for optimizing flexibility transactions within energy communities. This paper presents a model for quantifying and pricing residential resources flexibility, enabling prosumers to submit bids in an LFM managed by the Community Manager. The methodology relies on a linear optimization problem, where a Home Energy Management System first determines optimal consumption baselines. Then an iterative sensitivity analysis estimates upward, and downward flexibility bands and sets offer prices per resource. The market operates as two asymmetric voluntary pools, clearing flexibility offers and requests. Results show that Battery Energy Storage Systems and Electric Vehicles provide the most effective flexibility, significantly reducing energy costs. Future research should improve pricing mechanisms and scalability to support LFM adoption in different residential settings.

Abstract
Grid scale Battery Energy Storage Systems (BESS) have a key role for future power systems operation and stability. However, cyclic degradation, intensified by multi-service operation, remains a major challenge, directly affecting battery lifespan and profitability. This study examines BESS participation in energy markets and in automatic frequency restoration reserve (aFRR) markets, assessing the impact of cyclic degradation costs on BESS planning and operation. The methodology involved modelling the daily dispatch of an 8.1 MW lithium-ion battery for participation in day-ahead, intraday and reserve markets, incorporating a degradation cost minimization model. The simulations were conducted using the historical data from Iberian electricity and Portuguese ancillary services market, such as energy prices, historical reserve requirements and AGC forecasts. The results show that reserve market participation is highly profitable and can be successfully complemented with day-ahead and intraday market participation. Also, incorporating cyclic degradation cost into planning extends BESS lifespan in all cases. However, this approach is beneficial only in arbitrage scenarios, while in reserve market participation, it reduces profits. The findings highlight the importance of balancing BESS degradation minimization with profitability, particularly in reserve market participation. Future research could apply this model to different battery technologies and real-world systems to validate the simulated results.

Abstract
This work presents an approach to the flexibility of energy consumption in Renewable Energy Communities (RECs). A two-stage model for quantifying the flexibility provided by the domestic energy resources operation and its negotiation in a market platform is proposed. In stage 1, the optimal consumption of each prosumer is determined, as well as the respective technical flexibility of their resources, namely the maximum and minimum resource operation limits. In stage 2, this technical flexibility is offered in a local flexibility-only market structure, in which both the DSO and the prosumers can present their flexibility needs and requirements. The flexibility selling and buying bids of the prosumers participating in the market are priced based on their base tariff, which is the energy cost of the prosumers corresponding to their optimal schedule of the first stage when no flexibility is provided. Therefore, providing flexibility is an incentive to reduce their energy bill or increase their utility, encouraging their participation in the local flexibility market.

Abstract
This work performs a comparative analysis of battery energy storage system (BESS) participation in the multi-services electricity market, considering the optimal operating cost and better profitability for the BESS portfolios. A comparison of the application of these portfolios in different market conditions is proposed: (i) energy-only market, (ii) reserve-only market, (iii) sequential energy and reserve market, and (vi) joint energy and reserve market. For each BESS portfolio, hourly strategies for buying and selling offers are proposed, to maximize the revenue, accounting for the expected load and generation variations in the grid. The analysis of the BESS strategies is carried out through a case study based on actual generation data, where operating costs and BESS flexibility are assessed. One conclusion is that, even though, BESS makes a profit by participating in single markets, the best strategy is to participate in both energy and reserve markets, especially in the presence of a joint energy and reserve market model.