Hydrogen supply for ammonia manufacture (Indian context):\nWhich route is generally the costliest per unit hydrogen among the options listed?

Introduction / Context:
Large-scale ammonia manufacture requires a reliable and economical hydrogen source. In India, as elsewhere, hydrogen production economics depend on feedstock and energy prices. This item asks you to identify the generally costliest option among common industrial choices when evaluated on a levelized cost basis absent special subsidies for electricity.

Given Data / Assumptions:

• Conventional plant scales; grid or typical industrial power tariffs.
• Standard process configurations as used in fertilizer sectors.
• No extraordinary low-cost renewable power assumed for electrolysis.

Concept / Approach:
Steam reforming of natural gas (or naphtha where applicable) has historically delivered the lowest-cost hydrogen at scale. By-product recovery from coke oven gas can be attractive in integrated steel complexes. Electrolysis of water, while attractive for decarbonization, consumes large amounts of electricity; without very cheap power, its cost per kilogram H2 is higher than reforming-based routes, making it the costliest among the options under typical Indian industrial conditions.

Step-by-Step Solution:

Verification / Alternative check:
Sectoral reports consistently show electrolysis hydrogen costs exceeding SMR-based hydrogen unless power is available at very low tariffs and high capacity factors.

Why Other Options Are Wrong:

• COG recovery: leverages by-product gases; often economical.
• Naphtha and natural gas reforming: established lower-cost baselines.
• Fuel oil partial oxidation: typically cheaper than electrolysis on an energy basis.

Common Pitfalls:
Equating environmental preference with current cost; green does not always mean cheaper today, though trends are changing as renewable electricity costs decline.

Final Answer:
Electrolysis of water.