Comprehensive 4E (energy, exergy, economic, and environmental) assessment of a repowered natural gas-fired combined power plant

Abstract Natural gas-fired combined power plants (NGFCPP) stand out as a promising technology for electricity generation, boasting high conversion efficiency and relatively low carbon dioxide emissions. Numerous researchers have explored diverse strategies to further optimize the performances of these systems. The main aims of this work are to model the 4E (energy, exergy, economic, and environmental) performances of a new design of an NGFCPP and compare them to those of an operating conventional plant (Hadjret Enouss plant). The obtained results show that the plant operating with the new design achieved a higher energy efficiency of 63.77%, compared to the Hadjret Enouss plant’s 58.87%. Moreover, its exergy efficiency of 56.58% also surpassed the Hadjret Enouss plant’s 55.54%. Although the NPV of the new design was slightly lower at 764.57 M€ compared to the Hadjret Enouss plant’s 776 M€, the developed plant demonstrated superior sustainability with the lowest CO 2 emissions at 40.77 kg/s and the least cooling water consumption at 5.984 m³/s. In conclusion, this new design offers significant long-term benefits, with the potential to save a considerable amount of fuel and reduce environmental impact over its lifetime. For example, over 35 years of operation, the developed plant can save 154.526 million kg of natural gas compared to conventional NGFCPPs, leading to an annual reduction in CO 2 emissions of approximately 24.28 million kg.