Summary
- Real-world data collection and analysis show that hydrogen production efficiency at refueling stations is lower than expected.
- The Hydrogen Research and Fueling Facility in California is the first U.S. station certified to sell hydrogen commercially on a per-kilogram basis.
- The study on the station’s efficiency showed a significant variance in energy performance, with values ranging from 133 kWh/kg to 83 kWh/kg over the years.
- The efficiency of hydrogen refueling stations making their own hydrogen is expected to be lower than previously assumed, with actual values falling below the 60-70% range.
- Researchers found that the efficiency of the alkaline electrolyser at the facility was double the estimates used in previous modeling, highlighting the need for more accurate data in hydrogen studies.
Article
The efficiency of producing hydrogen at refueling stations has been brought into question by a recent study on the Hydrogen Research and Fueling Facility (HRFF) at California State University, Los Angeles. This station, which has been operational since 2014, produces hydrogen on-site using an alkaline electrolyzer and serves both campus vehicles and public fuel cell electric vehicles. Unlike most stations that receive gray hydrogen deliveries, the HRFF embodies the ideal scenario of producing hydrogen close to where it’s dispensed from renewable electricity.
A study by the International Council on Clean Transportation (ICCT) highlighted the model of green hydrogen manufactured at truck stations and used in fuel cell trucks, suggesting comparable costs to electric trucks charged at the same stations. However, further scrutiny revealed numerous errors in their hydrogen transportation studies, including using hypothetical future cost assumptions for liquid hydrogen pricing. Real-world data from California’s hydrogen refueling stations also showed a higher need for operations and maintenance, contradicting the assumptions of other studies.
The efficiency of hydrogen refueling stations making their own hydrogen is often overestimated in simplistic models, assuming 60% to 70% efficiency based on proton exchange membrane (PEM) electrolysis. However, the new study on the HRFF revealed a wide variability in efficiency over the years, ranging from 15% to 40%, with electricity requirements per kilogram of hydrogen far exceeding the ICCT’s estimates. This disparity highlights the importance of real-world data collection and analysis to accurately assess the performance of hydrogen infrastructure.
The study defines station efficiency in terms of overall energy performance, comparing the energy output of dispensed hydrogen to the station’s total electricity demand. Key components such as the electrolyzer, storage compressors, booster compressors, dispensing line, and overall site energy systems were included in the assessment. Despite improvements in efficiency over time, the HRFF’s performance still falls short of common assumptions used in cost calculations for hydrogen transportation.
The discrepancies between actual efficiency data and assumed levels suggest a need for greater transparency and realistic modeling in hydrogen infrastructure assessments. Real-world studies like the one on the HRFF provide valuable insights into the challenges and limitations of hydrogen refueling stations, helping to inform future developments and policy decisions. As the cleantech revolution continues to accelerate, accurate and unbiased analysis of hydrogen technologies will be crucial in shaping the transition to a more sustainable energy future.
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