Farnam Dehghani, Mohammad Agha Shafiyi, Mohammad Reza Arabshahi
• Proposed a stochastic optimization framework for renewable integration in multi-carrier energy systems under uncertainty. • Introduced novel cost-reduction measures such as oxygen extraction, heat recovery, and green desalination. • Showed that combining efficiency gains with complementarity leads to significant additional savings. • Compared zero curtailment scenarios with penalty-based curtailment for private renewable power plants. • Addressed the overlooked role of complementarity in RES permitting, highlighting its potential to lower costs. Economic challenges are a major barrier to achieving a low-carbon energy system with high penetration of renewable energy sources (RESs). Because RESs are variable and unpredictable, addressing these challenges often increases costs. Therefore, this paper proposes novel techniques to reduce the costs of integrating RESs into the energy system. Several strategies, such as oxygen extraction, heat recovery, and green water desalination, are introduced to improve system efficiency, whereas the economic complementarity of hybrid renewable sources is used as a means to manage integration costs more effectively. A mixed-integer nonlinear programming (MINLP) model is developed and solved using stochastic programming in the GAMS environment. To establish a baseline for comparison, various scenarios are analyzed. These include zero-energy curtailment and penalty-cost curtailment under different RES penetration levels, and the impacts of economic complementarity and energy efficiency strategies. The combined effect of economic complementarity with existing methods such as load tracking and Pearson correlation is also examined. The optimization results show that using penalty-cost curtailment reduces costs more effectively than zero-energy curtailment. Energy efficiency improvements lower costs by up to $19 million, and economic complementarity achieves savings of up to $50 million. Overall, economic complementarity outperforms traditional methods, reducing costs by $9–28 million per year under different RES penetration levels. In addition, C O 2 emissions decrease by 1.73 million tons compared to a system without RES integration. The social acceptance rate of the system also improves, which reflects both environmental and economic benefits.