Life cycle assessment of hydrogen production, storage, and utilization toward sustainability

In the pursuit of sustainable energy solutions, hydrogen emerges as a promising candidate for decarbonization. The United States has the potential to sell wind energy at a record-low price of 2.5 cents/kWh, making hydrogen production electricity up to four times cheaper than natural gas. Hydrogen's appeal stems from its highly exothermic reaction with oxygen, producing only water as a byproduct. With an energy content equivalent to 2.4 kg of methane or 2.8 kg of gasoline per kilogram, hydrogen boasts a superior energy-to-weight ratio compared to fossil fuels. However, its energy-to-volume ratio, exemplified by liquid hydrogen's 8.5 MJ.L⁻¹ versus gasoline's 32.6 MJ.L⁻¹, presents a challenge, requiring a larger volume for equivalent energy. In addition, this review employs life cycle assessment (LCA) to evaluate hydrogen's full life cycle, including production, storage, and utilization. Through an examination of LCA methodologies and principles, the review underscores its importance in measuring hydrogen's environmental sustainability and energy consumption. Key findings reveal diverse hydrogen production pathways, such as blue, green, and purple hydrogen, offering a nuanced understanding of their life cycle inventories. The impact assessment of hydrogen production is explored, supported by case studies illustrating environmental implications. Comparative LCA analysis across different pathways provides crucial insights for decision-making, shaping environmental and sustainability considerations. Ultimately, the review emphasizes LCA's pivotal role in guiding the hydrogen economy toward a low-carbon future, positioning hydrogen as a versatile energy carrier with significant potential.