Dra. Matamala-Aguayo, Yolanda

Determining a fair trading price is challenging, and this complexity is further heightened in power systems as the price must consider network constraints, fluctuating and endogenous electricity prices, and generation cost. This paper proposes a novel Nash-in-Stackelberg model designed to coordinate a collection of independently operated microgrids. Within this framework, the microgrids engage in a bargaining game to collectively decide a fair trading price as well as other operational decisions. We use the Nash bargaining solution (NBS) to model this interaction. Microgrids’ trading decisions impact the locational marginal prices of the main power grid. Hence, a Stackelberg game is used to determine these prices. The Stackelberg model considers microgrids as leaders (upper-level problem) and the independent system operator as follower (lower-level problem). The NBS guarantees a fair allocation of the generated profit based on individual characteristics of the microgrids. In specific, in scenarios of higher generation, we achieve a cost reduction of $ 884 and $ 904 per microgrid compared with a grand coalition where only one microgrid receives the total cost reduction ( $ 1788). Also we noticed that increasing the amount of solar-generated electricity reduces the nodal price in 1.53% and consequently the trading price in 1.27%.

Technologies providing flexibility options to power systems, such as Power-To-X (PtX) technologies, have become more important with the increasing deployment of distributed energy resources, particularly microgrids. However, uncertainty in renewable resources creates ambiguity regarding the necessary PtX capacity to install. This paper proposes a two-stage stochastic Stackelberg approach for multi-energy microgrids, focusing on long-term investment decisions in PtX technologies and hourly operational strategies. The Stackelberg problem considers microgrids as leaders (upper level) and the independent system operator as a follower (lower level). In the first stage, investment levels for various PtX technologies are determined as one-time decisions. The second stage focuses on hourly operational decisions, including the integration of microgrids with the independent system operator with marginal endogenous prices. The results provide insights into how uncertainty in renewable generation and electric battery levels affect investment levels. Larger hydrogen and thermal storage volumes lead to more flexible and self-sufficient microgrid systems. In scenarios with higher flexibility, microgrids can: (1) satisfy up to 10% of the independent system operator demand using renewable electricity and (2) regulate supply variability by storing excess generation during peak periods and releasing it during low generation periods.

In order to reduce greenhouse gas emissions, countries worldwide are transforming their energy systems with higher shares of renewable energy and smart technologies for demand response. Microgrids play an essential role in the transformation of electric grids to smart grids. However, renewable sources present new challenges, particularly those of high variability, which creates uncertainties in the supply side that can affect the security of electricity access at affordable prices. This paper proposes a novel Stackelberg stochastic model to account for different sources of uncertainty. The Stackelberg model considers microgrids as leaders (upper-level problem) with uncertainty regarding the availability of wind and solar sources and electricity prices. Availability of renewable sources is modeled via chance constraints, which allows assessing the risk of microgrids over-committing supply levels. Uncertainty in electricity prices is modeled via a set of demand scenarios with a given probability distribution. The lower-level problem of the Stackelberg problem considers an electricity dispatch problem for each demand scenario. The proposed model allows measuring the strategic actions of microgrids when facing different types of uncertainties and how the smart grid should adapt to guarantee that demand levels are supplied. The results show the effectiveness of the proposed method. We find that microgrids risk levels above 30% do not correlate with further benefits, such as reduced electricity prices. We also identified that in average, depending on the social cost of carbon and demand level, microgrids can cover their own demand and supply 15% of the electricity demand in the grid.