Techno-economic analysis of a multi-energy complementary distributed low-carbon energy supply system for island natural gas processing station

Island natural gas processing stations on remote islands commonly face the triple challenges of low energy efficiency, high energy consumption, and significant carbon emissions. To address these issues, this study innovatively proposes and designs a distributed multi-energy complementary low-carbon energy supply system that deeply integrates natural gas power generation, photovoltaic green electricity, and cascade utilization of waste heat, aiming to replace the traditional separated energy supply model of "coal for electricity and gas for heat." The core innovation lies in constructing a "source-grid-load-storage" collaborative architecture precisely matched with the processing technology, achieving a paradigm shift in energy utilization from "fuel combustion" to "combined heat and power generation with green electricity quality enhancement." Evaluation of two proposed Schemes demonstrates that both achieve significant performance improvements while ensuring a stable energy supply: Scheme 1 reduces energy consumption by 21.6 % and carbon emissions by 35.5 %, whereas Scheme 2 achieves 15.3 % energy savings and 27.5 % emission reductions. Economically, both models yield annual energy cost savings on the scale of millions of CN¥. Scheme 1, in particular, shows a payback period of 7.17 years and an internal rate of return (IRR) of 13.1 %, indicating sound economic viability. The capacity sensitivity analysis conclusively shows a trade-off for Scheme 1: lower operating costs adversely impact investment metrics, including payback period, IRR, and net present value. This research provides a replicable pathway for the low-carbon transformation of energy-intensive facilities in remote island areas, highlighting the considerable potential of integrated multi-energy systems in achieving synergistic energy optimization.