Greenhouse Gas Emissions from LNG Infrastructure Construction: Implications for Short-Term Climate Impacts

Switching from coal to imported, low-emission liquefied natural gas (LNG) has the potential to be an effective interim measure for meeting short-term climate goals by reducing greenhouse gas (GHG) emissions from electricity generation. To make this switch on a large scale, the LNG supply chain will require significant new infrastructure. Radiative forcing from construction emissions will cause climate disbenefits until the time at which operational emission reductions due to switching fuels compensate for the construction emissions (the breakeven time). This work presents emission estimates for constructing LNG supply chains, including liquefaction facilities, transport ships, regasification facilities, pipelines, and power plants. Supply chain- and location-specific estimates of breakeven times for specific realistic fuel switching scenarios are estimated, taking the timing of construction emissions and the temporal variation of the GHG potency of methane relative to carbon dioxide into account. Breakeven times can range from 1 to 20 years or more, depending on a variety of factors, but particularly natural gas sourcing and land use changes associated with pipeline construction. Supply chains and infrastructure construction emissions both play a role in determining the short-term favorability of fuel switching.