Greenhouse gas emission (GHG) associated with LNG have come under increased scrutiny from governments and market participants in recent years. Global LNG trade has more than tripled since the beginning of the century, while GHG emissions from LNG supply and end use had reached an estimated 1.25 Gt CO2-eq (~17% of emissions from natural gas) by 2020.
Expectations
of tightening future regulations and emission standards are set to drive investment
in GHG emissions reduction measures over the medium term. Meanwhile, emission intensity
is emerging as a critical differentiator among LNG projects, as lower emission profiles
are seen as a natural hedge against regulatory uncertainties.
LNG Value Chain Emissions
Emissions throughout the LNG value chain consist primarily
of methane, carbon dioxide and nitrous oxide – three greenhouse gases. Emissions
occur along the whole value chain and product lifecycle. GHG emissions associated
with LNG can generally be categorised into five types: combustion-related, vented
emissions, fugitive emissions, transportation-related and non-routine emissions.
Emissions can also be segmented operationally along the
LNG value chain: upstream supply, liquefaction and production, shipping, regasification
and downstream use.

The biggest share of emissions comes from the actual use
and combustion of natural gas, accounting for at least two-thirds of total lifecycle
emissions. Transportation distances also impact the level of potential fugitive
methane emissions. This could be the distance from upstream field to LNG plant,
from LNG loading port to destination port or from receiving terminal to end-user.
Upstream
Production Emissions Focus
As
far as most LNG suppliers are concerned, the emissions within their control are
up to LNG delivery point, which could potentially account for one-third of total
lifecycle emissions. Assuming the LNG supplier is also the LNG producer, the largest
area to tackle with regard to emissions reduction is upstream gas production and
the liquefaction process.
Carbon
capture and storage (CCS) technology can help address emissions from the upstream
and production portion of the LNG value chain. Some LNG production plants currently
have CCS projects associated with it, but many projects are trying to tag on a CCS
unit to projects in order to make them more sustainable.
Key Operational LNG CCS Facilities
Currently
only Snøhvit LNG in Norway and Gorgon LNG in Australia are using CCS in association
with their upstream operations.
Qatar
announced in October 2019 the commissioning of a CO2 recovery and sequestration
facility in Ras Laffan with a capacity of 2.1Mtpa. The North Field East LNG project
is set to be developed in association with a CCS facility, integrated into the wider
CCS scheme in Ras Laffan. Qatar Petroleum’s
sustainability strategy states that the company aims to capture more than 7Mtpa
of CO2 emissions by 2030.
Russia’s
Novatek is currently investigating the potential to develop CCS-based solutions
to reduce the carbon intensity of its operations associated with LNG production.
The company is targeting a final investment decision (FID) by 2022.
BP
is considering the development of the Ubadari field in Indonesia in association
with a CCS project to supply Tangguh LNG. Besides CCS, the emission intensity of
feed gas supply can be reduced through the mitigation of methane leaks/venting and
the electrification of compressor stations along the transmission system.
Norway
In Norway, Equinor’s Snøhvit CO2 Storage facilities form
part of the development of gas fields in the Barents Sea, offshore Norway. The Snøhvit
field supplies gas to the world’s first LNG plant with CO2 capture and
storage. Snøhvit LNG Project consists of nine wells, eight for production and one
for injecting carbon dioxide. CO2
is captured at the Hammerfest LNG Terminal on the island of Melkøya, northern Norway,
where the offshore sourced gas stream is processed.
CO2
is returned to the gas fields by pipeline for injection into the Stø reservoir at
a depth of 2,600m. The facility is designed to capture 0.7Mtpa. More than 4Mt of CO2 has been stored to date since
2008.

Australia
Chevron’s Gorgon CO2 injection facility is part of the
wider Gorgon LNG project offshore Western Australia (WA). The
CO2 Injection Project is the largest of its kind in the world, and represents the
largest greenhouse gas abatement project undertaken by industry. Reservoir CO2 is separated and compressed at the facilities
located on Barrow Island and then piped a short distance to CO2 injection wells
on the Island where the CO2 is injected into the Dupuy Formation beneath Barrow
Island.
The CO2 injection started in August 2019. The CO2 capture
capacity is at 3.4 – 4.0Mtpa and this will reduce greenhouse
gas emissions from the Gorgon Project by approximately 40%. It is expected that 100Mt of CO2 will be injected
into the Dupuy Formation over the life of the Gorgon Project.
Some
22 months after this CCS system start up, about 4Mt of CO2 has been sequestered. The system has however never reached capacity
due to problems with the pressure management system which Chevron expect to be operational
this year.

Qatar
Qatargas currently separates CO2 in the Ras Laffan LNG
production facility from its North Field. CO2 injection started in 2019. Ras
Laffan has become the largest CO2 recovery and sequestration facility in the Middle
East and North Africa region. The CO2 capture and storage capacity are approximately
2.1Mtpa. Qatar
is growing its CCS projects with a plan to store more than 5Mtpa of CO2 by 2025.
The move is closely linked to the country's target of growing its LNG volume.
The
North Field LNG Expansion Project will increase Qatar's LNG production capacity
from 77Mtpa to 110 Mtpa, which accounts for an LNG production capacity increase
of approximately 43%. Production of first
gas from the expansion project is expected by the end of 2023.