What is Liquified Natural Gas? – DW – 07/14/2025

DW

5 hours ago

Louisiana is the latest US state to label LNG as "green" energy. But how can a fossil fuel that emits many planet-heating greenhouse gases be clean?
The Gulf Coast state of Louisiana, home to the largest liquified natural gas (LNG) export facility in the US, has recently rebranded the fossil fuel as "green" energy.
It is the fourth Republican majority state after Indiana, Ohio and Tennessee to have taken this step and comes as US President Donald Trump rolls back renewable energy subsidies and incentives in favor of oil and gas.
The US is the world's biggest exporter of LNG, much of which has been shipped to Europe since 2022, when Russian gas supply was slashed following the invasion of Ukraine.
That hasn't stopped the European Union from also classifying natural gas-powered electricity, now sourced largely from imported LNG, as green energy in some contexts. The reasoning is that it is a more sustainable way to transition to renewables like solar and wind since it has a lower carbon footprint than coal.
But critics point to a leaky and energy-intensive supply chain that releases a lot of planet-heating methane into the atmosphere.
Though it also contains small amounts of ethane, propane, butane and nitrogen, Liquid Natural Gas is more than 90% methane.
Methane accumulates in the atmosphere for only around 12 years, as opposed to CO2 that persists for centuries, but it has an outsized impact on the climate.
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For one thing, LNG is around 85 times more powerful than CO2 over a 20-year period.
Scientists estimate that while methane only accounts for 3% of greenhouse gas emissions since 1750 — the beginning of industrialization — it is responsible for 25-30% of the subsequent global warming.
One 2024 study concludes that LNG has a 33% larger greenhouse gas footprint than coal over 20 years, due in part to methane leakages in the supply chain and energy-intensive processing and shipping. "Natural gas and shale gas are all bad for the climate. Liquefied natural gas (LNG) is worse," said Robert Howarth, lead author of the study and professor of ecology and environmental biology at Cornell University.
In the United States, LNG is made up of gas that is mined from underground shale using a method called hydraulic fracturing, or fracking. This in itself is a controversial process, which critics say pollutes water supplies and air, as well as devastating habitat and biodiversity. Once it has been pulled from underground, the gas is piped to coastal processing plants and supercooled to around -161 degrees Celsius (-258 degrees Fahrenheit) to create a clear, colorless liquid.
This liquified gas is much more compact, having been reduced to around 1/600th of its original volume. As such, it can be stored and transported long distances on "cryogenic" LNG tankers that keep the gas very cold, including to locations not accessible by pipelines.
When the LNG arrives at purpose-built terminals, it is regasified and piped into the existing gas network.
So while European countries once received most of their gas directly from Russia via land and sea pipelines, many have been building LNG terminals to ship gas primarily from the US, but also Qatar and Algeria.Imports from the US dropped by 19% in 2024 from the highs of the previous year. However, Russian supplies entring the bloc in 2024 went up by 18%. That is despite a commitment to phase-out imports from the country by 2027.
Natural gas has long been touted as a "bridge" fuel to a fossil-free energy system because it has around half the carbon emissions of coal.
This premise has helped governments claim that LNG is a relatively clean energy source.
But beyond the potent methane emissions associated with shale gas fracking in the US — the source of most LNG in the country — supercooling, shipping and regasification require a lot of emission-intensive energy.
Designating LNG as a green component of a climate-neutral energy future will be difficult as coal plants close and methane becomes the biggest greenhouse gas polluter.
Methane is likely responsible for as much as 50% of temperature rise in the last decade, said Howarth at a Climate Change Conference in Bonn, Germany in June 2025.
LNG is also expensive. Experts claim that energy produced using LNG costs up to five times more than renewables like solar and wind.
So, where does this leave the decision by US states like Louisiana to relabel LNG as green and climate-friendly?
As the window rapidly closes on keeping temperature rise below 2 degrees and avoiding "irreversible climate catastrophe" — already becoming evident in more extreme heatwaves and wildfires globally — Howarth cautions that Liquified Natural Gas has no place in a clean energy future.
"LNG has the largest greenhouse gas footprint of any fossil fuel," he said. "There's simply no room for that."
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