The energy sector is experiencing a transformative shift driven by global decarbonization mandates, technological advancements, and the need for infrastructure modernization. Amid this transition, energy firms are increasingly engaging in capital expansion and corporate restructuring to enhance operational efficiency, enter new markets, and align with sustainability goals. These strategic maneuvers, however, come with substantial financial risks, making cost control an essential element of success. This explores recent advances in strategic cost control tailored to energy firms undergoing such transformative initiatives. Emphasis is placed on the integration of advanced costing methodologies, digital tools, and innovative project management practices that ensure both cost containment and value maximization. Key developments include the application of Activity-Based Costing (ABC) and Life Cycle Costing (LCC), which provide granular cost visibility across project phases and asset lifespans. Predictive analytics and artificial intelligence are increasingly utilized for dynamic cost forecasting and early identification of cost deviations. Additionally, lean management and value engineering are being adapted to energy infrastructure projects to optimize resource utilization and eliminate inefficiencies. The use of Integrated Project Delivery (IPD) models and milestone-based contracting further align cost accountability across stakeholders during capital expansion. In the context of restructuring, firms are adopting shared services, digital transformation, and portfolio optimization to streamline operations and reduce overhead. Case studies from both fossil fuel and renewable energy sectors illustrate how these cost control mechanisms contribute to improved project outcomes and financial resilience. Despite these advancements, challenges such as data integration issues, regulatory compliance, and organizational resistance remain persistent barriers. Overall, this underscores the importance of adopting a holistic and forward-looking approach to cost control, integrating technology, governance, and strategic alignment. Such advances not only support financial sustainability but also enhance competitive positioning in a rapidly evolving energy landscape.