CH₄ Methane Slip

Unburned methane passing through LNG-fuelled engines. Methane has ~28× the 100-year warming potential of CO₂, so slip can erode the climate advantage of LNG substantially.

PollutantsLNG

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

m_{\text{CH}_4} = \frac{P \cdot h \cdot S_\text{cycle}}{10^6}

Symbol	Meaning	Unit
$m_{\text{CH}_4}$	Annual methane mass	t
$P$	Average engine power	kW
$h$	Annual operating hours	h
$S_\text{cycle}$	Slip rate by engine cycle	g/kWh
$GWP$	28 (100 yr) or 82.5 (20 yr)

Source: Fourth IMO GHG Study 2020; IPCC AR6 - methane GWP

In short

Estimate methane slip from LNG-fuelled marine engines and convert to CO₂-equivalent using GWP100 and GWP20.

Learn the theory Engine Performance Monitoring: PMI Systems