No Silver Bullet in Shipping: Data Will Decide the Next Fuel

The shipping industry stands at a defining crossroads. For over a century, heavy fuel oil has powered global trade, but its massive CO₂, SOx, and NOx footprint can no longer be ignored. LNG promised a cleaner bridge, yet new evidence of methane slip casts doubt on its true climate benefit. Ammonia, the carbon-free candidate, is emerging, but comes with toxicity, infrastructure, and NOx challenges. The choices made today will lock in trillions in investments and determine whether maritime becomes a climate leader or a laggard. The real question isn’t which fuel looks best on paper, it’s which pathway we can prove delivers genuine reductions. Without transparent, verifiable data, every promise risks becoming greenwash.

1. The Era of Fuel Oil

For over a century, fuel oil, specifically heavy fuel oil (HFO), has powered the backbone of maritime transport due to its energy density, availability, and cost-effectiveness. In the late 19th and early 20th centuries, ships gradually transitioned from coal to oil, as oil offered cleaner handling, easier storage, and higher energy density. By the 1920s, most new merchant and naval vessels were built with oil-fired boilers, and by the 1950s, fuel oil had almost entirely replaced coal in global shipping.

Yet the environmental toll of HFO is steep. Burning one ton of HFO emits roughly 3.1 tons of CO₂, making international shipping responsible for about 2–3% of global CO₂ emissions annually (IMO, 2020 GHG Study). In addition, HFO contains up to 3.5% sulfur by mass (before IMO 2020 regulations), producing high levels of SOx (sulfur oxides), which contribute to acid rain and respiratory illnesses.

• In the early 2010s, international shipping consumed around 178 million metric tonnes per year of HFO, and it accounted for 5–10% of global SO₂ emissions, or 7–15 million tonnes annually, equivalent to roughly 19,000 - 41,000 tonnes of SO₂ per day. (Wikipedia.org) These figures underline the staggering pollution burden from fuel oil, even before IMO’s 2020 sulfur cap took effect.

• NOx (nitrogen oxides) emissions from fuel oil combustion account for 15% of global anthropogenic NOx, contributing to smog, ozone formation, and further climate warming. (imo.org)

The IMO 2020 sulfur cap mandated a maximum sulfur content of 0.5% (down from 3.5%), reducing SOx pollution dramatically. However, the carbon footprint of fuel oil remains stubbornly high, and NOx continues to be regulated separately under IMO Tier II and Tier III standards. Fuel oil has been a workhorse, yes, but its route has led us to a crossroads: a fuel that once powered global progress is now at the center of the climate challenge.

2. Transition Into LNG – Benefits, Reality, and Rift

LNG emerged as a promising transition fuel, offering about 25–30% lower CO₂ emissions and near-elimination of SOx compared to HFO. But its Achilles heel is methane slip, which allows unburned methane, a greenhouse gas with ~84× the 20-year warming potential of CO₂,to escape. (Energy.ec.europa.eu)

The messaging journey has been troubling:

• Initially, industry giants claimed methane leak rates were “near zero,” encouraging countries to invest in LNG infrastructure and lock into long-term supply contracts.

• Later, official numbers acknowledged 1–3% methane slip, already sufficient to offset potential CO₂ savings.

• Most recently, independent research (using drone and helicopter measurements) recorded average methane slip rates of 6.4% over 18 LNG-fueled ships, double EU and IMO assumptions of ~3.1–3.5%. (theicct.org)

These findings underscore the dangers of relying on industry-reported data without independent verification. Startups like Emission‑Eye, offering real-time, transparent monitoring, aren’t nice-to-haves, they’re essential to avoid climate misdirection.

These findings underscore the dangers of relying on industry-reported data without independent verification. Startups like Emission‑Eye, offering real-time, transparent monitoring, aren’t nice-to-haves, they’re essential to avoid climate misdirection.

3. Transition Into Ammonia Engines – A Carbon-Free Fuel with Caveats

Ammonia (NH₃) is gaining traction as a truly carbon-free fuel at the point of use, no CO₂ or methane emissions when combusted (oxforgenergy.org). But the path to commercialization is strewn with hurdles:

• Toxicity and Safety: Ammonia is poisonous and corrosive, accidental leaks pose serious risks to crews and marine environments. (Reuters)

• NOx / N₂O Emissions: Combustion can produce NOx and N₂O, a potent greenhouse gas ~273× stronger than CO₂ over a 100‑year horizon. Even tiny emissions (≥0.4% of fuel nitrogen) could negate its climate advantage

(Reuters)(unece.org)(ammoniaenergy.org)

• High Production Footprint: Most current ammonia is derived from fossil-based Haber–Bosch processes. Even "green ammonia", produced via renewable hydrogen, is energy-intensive and costly. (financial times) (Reuters)

• Infrastructure Challenge: New global storage, bunkering, and handling systems must be built at massive scale, adding tremendous CAPEX before commercial deployment can scale. (climateworks.org)

While ammonia holds long-term promise, getting there will require heavy upfront investment, coupled with technical advances in emissions control and safety systems.

4. Budget Pathways – What Option Delivers More Capital Efficiency?

Here’s a strategic rundown of the three paths ahead:

A. Keep Fuel Oil + CCS

• Uses existing infrastructure, thus lower initial CAPEX.

• Retrofitting with carbon capture systems (CCS) buys time and avoids completely abandoning legacy assets.

• But it still perpetuates fossil reliance and offers limited emissions reductions compared to transitioning fuels.

B. Shift to LNG + Methane Capture

• Builds on existing LNG infrastructure but still demands new bunkering, ships, and terminals.

• Methane monitoring and capture systems are complex and costly.

• Leaves the industry exposed to the risk of stranded LNG assets if global policy shifts rapidly.

C. Shift to Ammonia + NOx/N₂O Control

• Highest short-term capital burden: requires brand-new infrastructure and advanced emissions treatment systems.

• Offers long-term climate potential: but only if ammonia is green and emissions from NOx/N₂O and toxic leaks are tightly managed.

In the short term, fuel oil + CCS is capital-efficient; LNG is the middle path; ammonia is most costly. In the long term, however, ammonia may offer the most sustainable alternative, if production, emissions, and safety challenges can be addressed.

5. The Common Denominator – Big Data, Unified Monitoring & Analytics

Regardless of the chosen path, fuel oil+CCS, LNG, or ammonia, the single truth remains:

Without accurate, real-time monitoring, we cannot truly know whether emissions are being reduced or merely shifted.

• Fuel oil + CCS demands verification of CO₂ capture efficiency.

• LNG requires stringent tracking of methane slip across supply chains.

• Ammonia needs continuous monitoring of NOx, N₂O, and toxic leaks.

Without verified data and analytics, greenwashing risks proliferating, and trillions in capital could be misallocated. Emission-Eye's unified emissions intelligence platform offers the visibility and confidence stakeholders, from regulators to financers, need to guide transitions wisely.

6. Final Thoughts

There is no silver bullet, only disciplined sequencing backed by verifiable data. In practice, many fleets will mix pilot CCS on legacy tonnage, deploy LNG where methane controls and supply are robust, and start ammonia readiness for 2030s newbuilds along emerging green corridors. What separates leaders from laggards won’t be the fuel they promise, it will be the proof they can show.

By 2030, success will not be measured by the fuel we burn, but by whether we managed the transition with accuracy, integrity, and foresight. With the right data infrastructure, the maritime sector can lead in global climate action, not lag.