The global LNG industry continues to expand as natural gas plays a key role in the energy transition, serving as a bridge between carbon-intensive fuels and renewable energy sources. KBR experts have designed, built and commissioned some of the largest and most challenging LNG projects around the globe. Our LNG experience spans more than 50 years, during which time we have been responsible for over 30% of the world’s installed LNG capacity.
In this article, Sukhpal Basi, Principal Process Engineer at KBR, discusses how the LNG industry can move towards a more sustainable footing by focusing on decarbonisation of the LNG value chain via energy efficiency improvements and emissions reduction.
We know now that LNG has long been marketed as a cleaner energy alternative, but in LNG we’re now recognising that continued reliance on carbon-based fuels doesn’t provide the solution to climate change. Instead, LNG stands as a steppingstone in terms of a sustainable future.
In the short term, demand for LNG will continue to grow as part of the drive to displace more carbon intensive fuels from industrial and domestic consumption, before LNG itself is eventually replaced by renewable technology. This positions LNG as a transition fuel that bridges the gap between oil and coal, and future cleaner renewable energy sources.
The range of LNG demand forecasts shows considerable uncertainty in our rapidly evolving energy landscape. Meanwhile, pressure from activists and investors to accelerate decarbonisation of existing portfolios has led some companies to market ‘green LNG’ or ‘carbon neutral’ LNG cargoes. But what do these terms mean, and how reliable are the credentials of this cleaner LNG?
A typical LNG cargo of 70,000 tonnes equals about 200,000 tonnes of CO₂. Carbon offset credits have historically cost between $1-10 per tonne of CO₂, but with large price swings possible. More critically, buyers paying a premium for ‘Green LNG’ increasingly want verification through monitoring, reporting and verification systems.
The LNG value chain emissions challenge
LNG value chain emissions can be broadly split into downstream emissions, which typically account for about 75% of the total, and other emissions across the upstream, liquefaction and transportation segments. These figures aren’t set in stone though – actual emissions vary significantly depending on the source and quality of feed gas, liquefaction facility configuration, distance to market and regasification technology used.
Two main approaches have emerged to produce cleaner LNG cargoes:
- Carbon-neutral LNG: Offsetting greenhouse gas emissions generated across the LNG value chain through mechanisms that balance emissions against carbon removal projects (like reforestation) or GHG avoidance (such as wind farms). This approach doesn’t necessarily reduce actual emissions in the operation of the LNG value chain.
- Green LNG: Reducing LNG carbon intensity by minimising GHG emissions across the value chain. This approach doesn’t eliminate emissions but reduces them through specific measures designed to maximise thermal efficiency at each link in the value chain.
The growing demand for greener LNG stems from environmental, social and governance (ESG) requirements of both buyers and sellers. However, many lobbyists have started to label carbon offsetting as ‘greenwashing’ – seeing it as a quick fix to meet net-zero goals by buying credits instead of investing in operational efficiency, technological innovation or renewables integration.
A typical LNG cargo of 70,000 tonnes equals about 200,000 tonnes of CO₂. Carbon offset credits have historically cost between $1-10 per tonne of CO₂, but with large price swings possible. More critically, buyers paying a premium for ‘Green LNG’ increasingly want verification through monitoring, reporting and verification systems.
In a comparative study that benchmarked CO₂ emissions of nine facilities delivering LNG to North-East Asian power generation markets, the distribution of CO₂ emissions varied significantly across different segments of the value chain. Upstream carbon emissions ranged from a mere 0.1% in the best case to almost 38% of the entire chain’s emissions, while liquefaction-based emissions varied from 5% to 21%.
Given this variability, it’s crucial to identify emission sources throughout the LNG value chain to develop targeted, cost-effective mitigation strategies for each segment.
The performance of an LNG plant hinges on numerous factors – from feed gas composition and inlet conditions – to liquefaction technology selection, cooling medium and equipment design choices.
Planning for sustainability from design stage – early technical involvement is key to KBR’s approach
When approaching a new LNG facility design, incorporating sustainability principles from the earliest planning stages is key to creating a greener value chain. This is where KBR’s expert LNG team come in and can assist in the analysis and design of the highest performing facility. The performance of an LNG plant hinges on numerous factors – from feed gas composition and inlet conditions – to liquefaction technology selection, cooling medium and equipment design choices.
The technology then comes into this design stage to minimise the carbon footprint of a new LNG facility. There are various examples of technology which can be applied at this stage. As a technology led company KBR has expert understanding of the applicable technologies and supports clients in the analysis and selection of technological solutions.
Electric motors offer efficiency, reliability and operational simplicity, with fewer outages and longer maintenance intervals. Large electric motors with variable frequency drives allow refrigerant compressors to restart from settle-out conditions without depressurisation, avoiding refrigerant loss to the flare. This not only reduces emissions during restart events but improves overall plant reliability.
High-efficiency gas turbines have powered liquefaction facilities for decades. Switching to high-efficiency aeroderivative gas turbines can improve thermal efficiency by 10% compared to heavy-duty industrial gas turbines (44% vs 34%). Their wide operating speed range offers greater flexibility for turndown operations while maintaining efficiency across both the compressor and gas turbine.
Heat recovery systems. Installing heat recovery systems on gas turbine exhausts boosts plant thermal efficiency. This can be further enhanced with Heat Recovery Steam Generation (HRSG), using steam to drive turbines and provide heating.
Vacuum insulated piping. LNG transfer lines between storage tanks and offloading facilities can use vacuum insulated piping – a pipe-in-pipe system that reduces heat gain tenfold compared to conventional insulation. This minimises boil-off gas generation and improves thermal efficiency, particularly in large complexes with extended jetties.
Hydrogen blending. Reducing carbon footprint through hydrogen blending into the fuel gas network presents another option. Current gas turbines and fired equipment can typically handle up to 20% hydrogen by volume without combustor modifications. While existing facilities face infrastructure challenges for safely managing high-purity hydrogen, new designs can incorporate this capability from the start.
Off-specification gas recycling. During start-up, considerable quantities of off-specification feed gas are typically flared until meeting required specifications. Designing systems from the outset for recycling this gas back to the inlet during start-up or other transient operations can significantly cut emissions.
Refrigerant recovery systems. Purpose-built refrigerant recovery systems can capture refrigerant to storage (for later reuse) or re-inject hydrocarbons into LNG product, avoiding flaring during maintenance or after compressor trips.
Carbon capture utilisation and storage (CCUS). The largest carbon emissions within an LNG facility come from acid gas removal units and fired equipment. Designing for pre-combustion capture of acid gas streams is economically viable and increasingly considered for new projects. Facility layouts can also be optimised during design to accommodate post-combustion CO₂ capture from gas turbine exhaust stacks.
Incorporating these technologies at the design stage enables new LNG facilities to achieve significantly lower emissions than retrofitted existing assets. For new facilities, carbon intensity analysis during pre-FEED studies helps understand the relationship between CO₂ intensity and facility cost (tCO₂/tLNG versus $/tLNG).
Improve existing assets and the economics of greener LNG – use KBR’s consulting expertise
While designing new facilities for minimum emissions offers the greatest potential for carbon reduction, improving the performance of existing assets presents a different challenge. A large part of KBR’s design work is in this field. The emissions profile of any facility stems from its equipment type, process configuration, and operational practices. When comparing LNG facilities, CO₂ intensity – serves as a common metric for energy efficiency and emissions performance.
Three key strategies can improve CO₂ intensity for existing facilities:
- Improving energy efficiency
- Increasing LNG throughput by removing bottlenecks to utilise all installed margins
- Reducing trips and restarts to minimise flaring and achieve higher annual production
Identifying efficiency improvements requires thorough understanding of facility design and operating philosophies, current practices and potential design enhancements that improve efficiency without major changes or costs.
KBR’s expert consulting teams take a systematic approach to finding and quantifying opportunities. This involves initial data gathering, joint workshops with engineering and operations experts, opportunity screening using assessment matrices, and detailed assessment of the most promising ideas. For many opportunities, simulation models of the entire LNG process help determine relative differences in power requirements, fuel gas consumption, and thermal efficiency.
Our economic assessments can assign value to CO₂ emissions and/or fuel gas based on carbon taxes, carbon credit costs, feed gas costs, or LNG prices. As buyers increasingly demand verifiable green LNG cargoes, operators who can demonstrate actual emissions reductions rather than just purchasing offsets may command premium pricing in the market. This premium creates a market-driven incentive for investing in emissions reduction technologies and operational improvements.
Forging a sustainable path for LNG – take a holistic approach through KBR’s multi stranded expertise
Achieving truly green LNG through actual emissions reduction rather than carbon offsetting demands a concerted effort to examine both the operation and design of assets. While existing facilities realistically cannot achieve the CO₂ intensity of purpose-built low-emission plants, significant improvements remain possible with the right approach.
For new facilities, incorporating sustainability principles from the earliest design stages offers the greatest potential for minimising lifecycle emissions. By carefully selecting technologies and configurations with emissions reduction in mind, operators can substantially reduce their carbon footprint while maintaining operational efficiency.
As LNG continues its role as a transition fuel in the global energy mix, demonstrating commitment to emissions reduction through both new designs and retrofits of existing assets will be crucial to maintaining the industry's social license to operate. Through methodical analysis, appropriate technological choices, and ongoing performance monitoring, the LNG industry can steadily reduce its carbon intensity while supporting the world’s journey towards a more sustainable energy future.
KBR are proud to have pioneered many LNG firsts which have since been adopted as the gold standard. Our long-standing LNG client relationships bear testimony to our unparalleled project execution performance. We are excited to partner with our clients as LNG moves into its next phase in the energy journey.
Want to develop your LNG facility to the next level? We can help. Contact us
Jared Young, KBR Snr Director, BD on jared.young@kbr.com or Juan Gomez Prado, KBR Chief Technical Advisor on juan.gomezprado@kbr.com
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