## 1 Introduction  
In recent years, peer-to-peer (P2P) energy trading has emerged as a game-changing option in the energy industry, which provides prosumers (producers + consumers) with a dynamic way to actively engage in the market. Previously, prosumers, who are not only consuming but also producing energy, used to be limited to buying energy from utilities or conducting transactions within microgrid networks. However, the development of P2P trading has changed this environment by giving power to prosumers to trade their surplus energy directly with fellow participants, therefore increasing their benefits and simultaneously improving consumer advantages [1, 2]. These paradigm modifications are supported by technological innovations like blockchain and smart metering, which enable safe and transparent energy transactions between parties. By using these technologies, P2P trading goes beyond traditional centralized energy distribution methods and allows a decentralized energy ecosystem with improved efficiency, resilience, and sustainability. In microgrid systems, prosumers can choose to connect with a utility company and buy power or transact energy from other prosumers as shown in Figure 1. This model assumes that the prosumers know the required information through the broadcasting of signaling messages, which is possible due to the cooperative approaches of community-based controllers. The problem solved is really single medium access control in disguise. For instance, when prosumers are unable to meet their own energy needs with their small-scale production capacities, they can purchase or loan energy from other producers. Additionally, prosumers have the option of selling or lending any excess electricity to other prosumers [3]. This leads to the establishment of a dynamic environment, where not only centralized entities but also actions undertaken by individuals determine how energy flows through the grid, leading to its resilience and sustainability. Piclo in the United Kingdom, Sonnen Community in Germany, and Yeloha (in Boston) in the USA are examples of global P2P energy trading platforms. By showing several business models, as well as innovative solutions for P2P electricity exchange, these platforms reveal how much change this technology can bring to the existing world's energy balance, illustrate the potential for P2P trading to reduce grid congestion, enhance energy security, and create new revenue streams for participants by adjusting energy prices dynamically in response to local supply and demand conditions [4]. In South Korea, on the other hand, there was no progress toward the diversification of business models among P2P businesses since the Korea Electric Power Corporation (KEPCO) monopolizes all P2P electricity transactions. But since second half of 2024, KEPCO has started to consider the recent trend of allowing P2P energy trading in specific regions. In addition, taxation in Korea is based on a tiered pricing system, unlike the United States, which implements a Time Of Use (TOU)-type residential electricity cost system that takes peak load times into account. In order to overcome these issues, this work suggests a framework for P2P energy trading within South Korea's tiered pricing system. The system model is designed to develop a plan for the reactivation of P2P electricity trading in Korea through the development of a tiered pricing model. This paper also presents the average prosumer benefit as a time series, identifies factors affecting the transaction utility for the exact price model, and indicates the level of customer bill reduction before and after P2P energy trading in South Korea. However, while this study is applied specifically to South Korea's tiered electricity pricing system, the framework has potential adaptability to and relevance in other global markets. This study aims to obtain the Pareto curve through a multi-objective optimization technique using a Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D) [5,6].