Hydrogen supply routes for nitrogenous fertilizer production: Which commercial hydrogen source is typically the costliest for large-scale ammonia (nitrogenous fertilizer) manufacture?

Introduction / Context:
Ammonia plants require large volumes of hydrogen combined with nitrogen (Haber–Bosch process). Hydrogen can be produced from fossil routes (natural gas/naptha reforming, coal gasification, coke oven gas) or via electrolysis of water. Cost structure varies with energy prices, plant scale, and capital intensity.

Given Data / Assumptions:

• Conventional, fossil-based commodity ammonia plants operating at large scale.
• Grid electricity costs are typical and not heavily subsidized by renewable power purchase agreements.
• We compare levelized cost per unit of hydrogen.

Concept / Approach:
Electrolysis splits water using electricity, which is typically more expensive per unit of hydrogen than hydrogen derived from hydrocarbons (via steam reforming of naphtha or natural gas, coal gasification, or coke oven gas recovery). While electrolysis has decarbonization advantages when paired with low-cost renewable power, it remains the costliest route under conventional grid economics and current capital costs in many regions.

Step-by-Step Solution:

Verification / Alternative check:
Industrial benchmarks consistently show SMR/naptha reforming at the low end of cost, coal gasification higher, and electrolysis highest unless very low-cost electricity is available.

Why Other Options Are Wrong:

Common Pitfalls:
Equating environmental superiority with cost; green hydrogen can be cleaner yet costlier without cheap renewables or incentives.

Final Answer:
Electrolysis of water