Development of a Model, Guidelines, and Cost Analysis for Balancing Pipeline Safety and Efficiency with Hydrogen Blending

Blending hydrogen into existing natural gas pipelines introduces a unique trade-off between energy delivery efficiency and material integrity. On one hand, hydrogen embrittlement of steels increases the risk of fracture and fatigue failures in high-pressure pipelines. On the other hand, the lower energy density of hydrogen results in a higher pressure required to maintain a sufficient energy throughput. This work aims to identify design and operating condition ranges that can be used to minimize both risk and energy loss, as well as the expected maintenance/repair costs and revenues associated with those ranges. To achieve this, a pipeline fatigue failure model was developed using a combination of fracture mechanics approaches with laboratory data, and this model was combined with an energy flow prediction based on fluid properties determined using the REFPROP software. Both models were then evaluated under a wide range of input combinations to determine the optimal ranges for operating conditions and expected costs and revenues for those ranges.

Keywords: Hydrogen, energy flow, fracture, fatigue, risk modeling, cost analysis.