Economic and environmental assessment of natural gas-ammonia co-firing

초록

Ammonia has emerged as a sustainable energy source. It can be co-fired with natural gas in gas turbines, which reduces carbon dioxide emissions and is recognized as a next-generation energy solution; its economic and environmental viability depends on its production method. However, systematic comparisons regarding the influence of the source and characteristics of NH3 on techno-economics and environmental performance are limited. Therefore, we comprehensively evaluated the techno-economic analysis (TEA) and life cycle assessment (LCA) for the natural gas-ammonia co-firing power generation. The optimal alternative was determined using the multicriteria decision-making method's analytic hierarchy process (AHP). The levelized cost of electricity (LCOE) increased with higher co-firing ratios for blue and green ammonia, whereas it decreased for grey ammonia. Further, an increase in the co-firing ratio resulted in LCOE variation primarily influenced by NH3 fuel costs, with fuel-price sensitivity being highest for green, followed by blue, and lowest for grey. Uncertainty analysis demonstrated that grey NH3 is currently cost-competitive. By 2040, overall cost distributions will be shifted leftward, enabling blue and green NH3 to achieve cost-competitiveness at high co-firing ratios. The LCA indicated that green NH3 consistently achieved the lowest global warming potential (GWP), fossil resource scarcity (FRS), and relatively low ozone formation potential. In contrast, blue NH3 presented unfavorable trade-offs in ozone formation and FRS due to upstream supply chain factors. Consequently, AHP ranked natural gas combined cycle (NGCC) as the top choice in the short-term, while high co-firing with green NH3 (80-100 %) emerged as the optimal long-term strategy.

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