DNV EU Guideline for Reporting and Verifying Methane Slip: What Ship Operators Need to Know

The European Union is tightening its climate regulations for maritime transport, and one of the most critical areas of focus is methane slip—unburned methane released during LNG engine combustion. To support compliance, DNV has introduced a guideline for reporting and verifying actual methane slip under FuelEU Maritime, EU MRV, and the EU Emissions Trading System (ETS). This marks a significant shift from default emission factors to verified data, offering both challenges and opportunities for shipowners.

Why Methane Slip Matters

Methane is a potent greenhouse gas with a global warming potential 25 times higher than CO₂. While LNG is often promoted as a cleaner alternative to heavy fuel oil, methane slip can undermine its environmental benefits. Accurate measurement and reporting are therefore essential to meet EU climate targets and avoid penalties.

From 2025, methane slip will be included in FuelEU Maritime compliance calculations. By 2026, allowances for methane and nitrous oxide will be required under ETS, making precise reporting a financial necessity.

Key Features of the DNV Guideline

The guideline enables shipowners to move beyond default emission factors by using actual certified values, provided they are verified through approved procedures. This approach can significantly reduce reported emissions and compliance costs.

Verification Methods

• Test-bed and onboard measurements following IMO MEPC.402(83) principles.
• Engine load monitoring, averaged over 30-minute intervals.
• Continuous Emissions Monitoring Systems (CEMS) for real-time data.

These methods ensure transparency and accuracy, aligning with EU and IMO standards.

Financial and Operational Impact

Using verified methane slip values can deliver substantial savings. For example, reducing slip from 1.7% to 0.7% could save €1 million annually for a large container ship under ETS. This creates a strong incentive for shipowners to invest in measurement systems and engine upgrades.

Strategic Implications for Shipowners

• Compliance Advantage: Verified data reduces penalties and improves competitiveness.
• Technical Upgrades: Engine manufacturers offer retrofit kits to minimise methane slip, making verification even more valuable.
• Regulatory Alignment: The guideline complements IMO efforts and sets the stage for stricter EU climate targets in shipping.

Next Steps for Operators

1. Assess Current LNG Engine Performance and methane slip levels.
2. Implement Measurement Solutions such as CEMS or certified onboard testing.
3. Engage with Classification Societies like DNV for verification and certification.
4. Plan for ETS Costs by modelling potential savings from accurate reporting.

Conclusion

The DNV EU guideline is more than a compliance tool—it’s a strategic opportunity. By adopting verified methane slip reporting, shipowners can reduce costs, enhance sustainability credentials, and stay ahead of regulatory changes. As the EU accelerates its decarbonisation agenda, proactive action today will define competitive advantage tomorrow.