Comparison of different hydrogen-ammonia energy conversion pathways for renewable energy supply

Hydrogen and ammonia are considered promising energy carriers for renewable energy due to their environmental friendliness and medium- and long-term storage cost advantages. However, a single hydrogen or ammonia energy strategy generally cannot meet the demand, limiting widespread application. Here we consider the whole process of renewable energy generation-transmission-storage-consumption, and propose a hydrogen-ammonia combined operation strategy. Assuming a rated power of 40 MW for generation and 10 MW for demand, we compare five energy conversion pathways: hydrogen or ammonia pipeline transmission, high-voltage alternating current (HVAC) transmission with hydrogen or ammonia storage, and HVAC transmission with hydrogen-ammonia hybrid energy storage. Results indicate that for a transmission distance of 100 km, the most economical pathway is HVAC transmission with hydrogen-ammonia hybrid energy storage, with a net present value (NPV) of 39.31 M$ and a levelized cost of electricity (LCOE) of 0.081 $/kWh. Sensitivity analyses reveal that a 0.01 $/kWh increase in electricity price leads to NPV growths of 11.75-16.02 M$. This pathway achieves zero carbon footprint and saves 4.7M$ annually in carbon taxes. Compared to traditional production methods, this pathway is equivalent to reducing emissions by 94,189 tons.