IGEM response to DESNZ: Gas system in transition, security of supply consultation

Feb 2026

IGEM response to DESNZ: Gas system in transition, security of supply consultation

IGEM welcomes the opportunity to respond to the Department for Energy Security and Net Zero’s (DESNZ) consultation, Gas system in transition: security of supply, on behalf of our members. We support the Government’s recognition of the continuing importance of gas during the energy transition and its commitment to work with industry to ensure that energy security, resilience and infrastructure capacity is maintained through the 2030s and beyond.

IGEM is the UK’s professional engineering institution for gas, representing more than 150 years of continuous technical leadership in gas engineering, safety, standards and workforce competence. Our work underpins the safe, resilient and efficient operation of the gas system today while supporting the transition to a net zero energy system in the decades ahead.

IGEM develops and maintains the UK’s core gas engineering standards and works closely with policymakers across DESNZ, HSE, Ofgem and the National Energy System Operator (NESO) to ensure that engineering evidence and whole-systems understanding inform the development of future energy policy.

The continuing importance of gas to system resilience

We agree with the consultation’s assessment that gas will continue to play a crucial role in providing dispatchable, flexible generation during periods of low renewable output, particularly during extended cold and still conditions.

Recent evidence illustrates this risk: in November 2024, prolonged calm and cloudy weather across the UK led to a sustained reduction in wind generation for much of the month¹. Longer-term analysis supports this pattern – multi-day low-wind events lasting at least 14 consecutive days occur approximately every five years², with longer events also recorded. For example, a 35-day low-wind period occurred between mid-August and mid-September 2022, and a further 19-day event took place in April 2022 during an extended heating season³. Together, these observations clearly demonstrate the continuing requirement for gas-based resilience within the electricity system.

National energy system discussions often focus on large-scale generation and transmission-level balancing, yet a significant portion of resilience sits within the distribution network itself. The gas-fired generation fleet connected at distribution level provides rapid, local flexibility that supports voltage stability, reduces network congestion and can defer reinforcement of both transmission and distribution assets.

Alongside this, combined heat and power (CHP) installations in commercial and industrial buildings supply on-site electricity while meeting thermal demand, providing highly efficient systems for their heat and power needs. Although these sites aren’t reliant on, or add stress to, the electricity supply system, they offer a flexibility opportunity to import electricity during low price periods and export when prices are high. These assets offer a major contribution to adequacy, operability and whole-system cost optimisation, particularly during periods of low renewable output.

Given this, maintaining adequate gas infrastructure capacity is essential. We support the Government’s intention to ensure that peak day demand can be met under low-probability, high-stress scenarios.

Value of domestic supply and the role of the UK Continental Shelf

Domestic sources of gas supply are critical for UK energy security and limit the exposure to imports, geopolitical risks and global price shocks. Although production from the UK Continental Shelf (UKCS) is in long-term decline, evidence suggests that the North Sea could still deliver almost twice the volume of oil and gas currently assumed in government forecasts⁴.

DNV’s latest UK Energy Transition Outlook report, concludes that significant amounts of oil and gas will still be required across the coming decade to balance energy demand and ensure security of supply⁵. Targeted extraction of remaining recoverable volumes should be considered as a route to strengthen security of supply for peak-day stress events.

Technical assessments also indicate that imported LNG has almost four times the carbon intensity of UK gas production⁶, reinforcing the environmental as well as practical case for maximising efficient domestic production.

Biomethane as a strategic asset

We strongly support the Government’s acknowledgement of biomethane’s role but are concerned that its exclusion from the consultation’s scope may inadvertently lead to siloed analysis.

Biomethane should be recognised and treated as a:

strategic, home-grown source of carbon-neutral gas, with the potential to become carbon negative
contributor to reduced import dependency, with the potential for up to 120TWh of UK production by 2050⁷
enabler of lower supply-margin risk on days of peak demand

In its Holistic Transition pathway, NESO positions biomethane as a practical whole-system solution that can be deployed now⁸. It describes biomethane scale-up as “a route to decarbonise gas supplies”, cutting emissions from residual gas use without waiting for full fuel-switching, while also improving “security of supply, using domestic feedstocks”. NESO notes that an independent assessment for FES 2025 found sufficient sustainable feedstock beyond levels required in its pathways, and points to European experience, particularly Denmark, as evidence that biomethane can scale rapidly with the right policies and supply chains. NESO also highlights biomethane’s role as a flexible low-carbon fuel for maintaining resilience during periods of system stress, such as low wind conditions.

The example of Denmark, with high biomethane penetration and a reversible gas system, provides valuable lessons for the UK in terms of enabling long-term system flexibility, storage utilisation and decarbonisation pathways⁹.

We therefore urge that future policy development fully integrates biomethane growth explicitly into gas security planning.

Whole-system considerations

A secure and resilient energy transition depends on the coexistence of multiple, complementary systems, rather than the displacement of any single vector or technology. Maintaining natural gas infrastructure during the transition provides essential flexibility and security of supply, while the expansion of biomethane enables immediate emissions reductions using domestic, renewable feedstocks. In parallel, the development of low-carbon hydrogen systems supports the decarbonisation of hard-to-electrify sectors and provides valuable system balancing. Underpinning all of these pathways is the consideration of CO₂ transport and storage infrastructure, which would enable carbon capture technologies to operate at scale. Together, these coexisting systems form the foundation of a secure, pragmatic and whole-system transition to net zero.

There is compelling research, including from Imperial College London¹⁰ that models the use of multiple energy vectors and technologies working together (electricity, natural gas, biomethane, hydrogen, heat networks and storage), which can deliver whole-system optimisation that materially reduces cost and creates a more resilient net zero system than relying on any single vector alone. Their findings show that flexibility across vectors is a major system value, and the adoption of hybrid systems with lower gas throughput can reduce electricity reinforcement costs, cut system-wide expenditure and strengthen overall resilience. This study, and others, consistently make the case that ‘gas system resilience is electricity system resilience’.

We encourage DESNZ to ensure that whole-systems modelling, across all gases, is embedded in future decisions.

Linepack as a major existing storage resource

The role of linepack remains under-recognised. Linepack provides one of the most important forms of short-term gas flexibility in Great Britain’s system, delivering approximately 100 TWh of annual cumulative storage across the gas networks¹¹, with theoretical capacity significantly higher¹². By varying pipeline pressures across the transmission and distribution networks, operators can store and release significant amounts of energy within a day, helping to smooth rapid changes in demand and maintain system balance without additional above-ground storage.

Linepack flexibility is essential during peak-demand periods and extreme weather events, where both the National Transmission System (NTS) and the Gas Distribution Networks (GDNs) use linepack to ensure gas reaches generators, industry and households exactly when needed.

Explicitly incorporating linepack into government security-of-supply modelling would ensure decisions fully reflect one of the system’s most effective operational tools.

Gas quality standards and the Wobbe Index

We welcome the Government’s recognition that current gas quality standards may limit system flexibility.

IGEM recognise that there is evidence to support raising the upper Wobbe Index limit to the existing emergency threshold of ≤52.85 MJ/m³, as detailed in our gas quality standard consultation document¹³. This change would:

reduce costs and emissions associated with nitrogen ballasting of LNG
facilitate a greater range of LNG supplies
remove a persistent barrier to enabling wider gas quality interoperability

Potential impacts of this change on Calorific Value (CV) and propanation of biomethane is actively being addressed through industry projects¹⁴. Changes to the CV-based billing framework will be essential to enable wider use of unpropanated biomethane and IGEM support accelerated progress in these areas to facilitate a more diverse and decarbonised gas supply.

LNG and floating storage considerations

While we recognise the role that LNG infrastructure will play as UKCS output declines over time, we encourage a cautious approach to new Floating Storage and Regasification Units (FSRUs).

Before pursuing capital-intensive LNG-based solutions, the UK can avoid import reliance by:

maximising North Sea extraction
maximising biomethane production
expanding domestic flexibility options, such as hybrid, cross-vector demand
ensuring all existing gas quality and regulatory barriers are addressed

By unlocking this potential and removing unnecessary constraints on greener gases, the requirement for new FSRUs could be materially reduced, supporting a lower-carbon, lower-cost and more resilient pathway for the gas system.

IGEM support the Government’s overarching intent to strengthen gas system resilience through the transition to net zero. However, a whole-system approach, encompassing biomethane, hydrogen, natural gas and CO₂ infrastructure, is essential.

We strongly encourage DESNZ to integrate the strategic role of biomethane, to accelerate changes to gas quality standards, and to ensure domestic system capability is maximised before expanding LNG-based solutions.

We welcome continued engagement with DESNZ to support the development of a secure, efficient and futureproof gas system.

Sources

Return to listing