Green Ammonia’s Long-Term Outlook in Bio-Bunkering

When we last looked at ammonia’s potential in low-carbon shipping in the blog, it was more of a vision than a deployed solution: trials, studies, and engines in development. Some further progress has been made with a big announcement on green ammonia’s adoption.

A breakthrough from Japan Engine Corporation (J-ENG) confirms this shift. In late August, J-ENG completed tests of what is being reported as the world’s first full-scale commercial dual-fuel ammonia engine, which can run on ammonia or heavy fuel oil.

This blog will cover what we know and what it means in both the short- and long-term bio-bunkering market

Key Milestones in Green Ammonia

• Successful Performance and Safety Tests: The J-ENG engine underwent rigorous trials under both ammonia and heavy fuel oil modes under supervision by major stakeholders. ClassNK has now certified its environmental performance and operational safety.
• Significant Emissions Reductions: The engine achieved more than 90% reduction in greenhouse gas emissions versus conventional heavy fuel oil. NOₓ emissions were about half of those from similar heavy fuel oil engines. Unburned ammonia “slip” was effectively managed to near zero via selective catalytic reduction (SCR) systems.
• Thermal Efficiency Maintained: Importantly, the engine doesn’t trade off efficiency for emissions. In ammonia operation, it showed thermal efficiency comparable to heavy fuel oil mode.

Scaling Technology to Operation

Ammonia in ocean shipping has largely remained in the domain of lab-scale or small prototype projects. Many questions persisted around emissions trade-offs, especially with NOₓ and ammonia slip, safety of storage and bunkering, and fuel infrastructure.

What makes this J-ENG development so compelling is that it addresses a number of those pain points in one package:

• Dual-fuel flexibility lets vessels run ammonia where feasible, or switch back to heavy fuel oil as backup, easing operational risk
• Certified safety and environmental performance help reduce regulator and stakeholder hesitation
• Comparable efficiency means lower penalties in fuel cost or power output

While highly promising, it’s important to emphasize the preliminary nature of this emerging technology. Factors like bunkering infrastructure, green ammonia supply, cost competitiveness, toxicity, and safety protocols all remain real issues. Nevertheless, the gap between what was theoretical/pilot and what is commercially proven has narrowed substantially.

What This Means for the Market

1. Ammonia is moving from “emerging” to “early commercial”
   The proof of a commercial engine being built, certified, and slated for real-world deployment makes ammonia a credible contender now, not just a future option.
2. Regulatory momentum and safety standards will matter
   Certification bodies (like ClassNK) and governments will need to align on bunkering safety, emissions standards (NOₓ, ammonia slip), and operational guidelines. Successful projects like this will help shape those norms.
3. Cost curves will be under pressure
   Early adopters may accept higher costs for the sake of first-mover advantage or regulatory positioning, but wider adoption depends on bringing costs (fuel, engines, operations, maintenance) closer to conventional fuels. Efficiency gains, economies of scale in production, and regulatory credits/incentives will play central roles.

Understanding Ammonia in Current Market Conditions

The horizon for ammonia in renewables-oriented marine application is looking much sharper. There is now a deployable engine, performance data that backs up emissions reductions without huge efficiency penalties, and a shipping company readying a vessel to go operational.

For companies considering bio-bunkering strategies, ammonia has considerable potential in long-term market outlooks. The pathway is visible: build the infrastructure, ensure green supply, align regulation, and manage safety.

The Road Ahead: Promise Versus Present Reality

Ammonia’s progress in shipping is remarkable. However, the industry isn’t there yet. Infrastructure, green ammonia supply chains, and regulatory alignment remain works in progress.

For companies operating today, this means balancing future potential with current realities. Decisions still hinge on the existing market for renewable feedstocks, established credit systems, and competing low-carbon pathways. And in a sector where upstream visibility is often scarce, that balance can be difficult to strike.

That’s where Prima CarbonZero comes in. Our platform provides the upstream perspective that the maritime industry typically lacks, with key pricing data, feedstock analytics, and expert commentary across the supply chain. From UCOME to UCO and beyond, Prima’s insights help you make informed choices today while positioning for tomorrow’s shifts into fuels like ammonia.

Learn more about how Prima CarbonZero can deliver the visibility, confidence, and clarity you need to navigate the transition.