Achieving net zero places a heavy emphasis on electrification, whether for heating, transport or power generation. To support the decarbonisation of domestic heat, the UK government aims to install 600,000 heat pumps per year by 2028.

Since the Boiler Upgrade Scheme was increased from £5,000 to £7,500 to encourage households to replace fossil fuel heating systems, the number of heat pumps installed has risen significantly. With this inevitable increase in electricity consumption, we must ask ourselves: How will Britain’s power grid withstand the additional strain, while supplying enough renewable power to meet demand?

UK is dependent on fossil fuels 
As a nation, the UK remains heavily dependent on natural gas for electricity production and heating. As inconvenient grid constraints and renewable storage technology still remain relatively new, the combined efforts of wind, solar and hydropower, for now, cannot provide enough reliable, on-demand access to power for the country. Although the UK needs to phase out fossil fuels – such as, coal, natural gas and oil – a zero-carbon form of gas has a critical role to play in the energy transition as a power source. A robust future system that provides reliable, affordable and sustainable energy must take an integrated approach by combining renewables, gas and nuclear.

Should ministers decide to introduce low-carbon gases like hydrogen or biomethane into the future mix, the current gas supply network cannot continue running unchanged. The replacement of natural gas would need to spark changes to production, distribution, storage and legislation to enable energy systems to function as required. Most importantly, we need to protect those who cannot financially afford to replace their heating system and are most at risk from energy transition tipping points.

Boosting production of low-carbon gas 
Biomethane made from biogas with organic matter, such as food and agricultural waste, is a carbon-neutral fuel. It is also indistinguishable from natural gas and, therefore, can provide a direct substitute. While hydrogen is the most abundant chemical element in the universe, it has limitations as a gas – being less than one part per million by volume. With modern technology, it can be made from a variety of sources. For example, ‘green hydrogen’ is produced using electricity generated from renewable sources, such as wind or solar, and therefore emits zero carbon. Both biomethane and hydrogen have the potential to play key roles in the decarbonisation of the UK’s energy system.

The government has set an ambitious target of 10 GW of low-carbon hydrogen by 2030, half of which will be green hydrogen generated from renewables. That level of production remains some way into the future; only about 5 MW of green hydrogen projects are currently operational in the UK. The government announced 11 new projects as part of the first round of the Hydrogen Production Business Model in December 2022. These projects, alongside future successful applications, will be essential to kick-start a baseline of production which could potentially help place the UK at the forefront of the hydrogen industry.

Alongside £2mn in hydrogen funding, the government also announced its support for blending up to 20% hydrogen into the gas networks, a decision which sparked optimism about the future of a hydrogen economy when it was announced in December 2023. However, optimism was swiftly followed by disappointment with the decision to cancel the hydrogen village trials due to difficulties in sourcing hydrogen and local opposition to the scheme. This demonstrates the need for a robust hydrogen economy, as well as an opportunity to start producing green hydrogen to meet government targets.

Changes to existing gas pipelines and data systems 
Hydrogen gas, H₂, is a very different molecule from methane, CH₄, which makes up the majority of natural gas. Hydrogen molecules are three times smaller than natural gas. When hydrogen is blended into the natural gas supply, at ratios of up to 20%, there is no need to modify existing gas pipelines or appliances. But if the long-term goal of the government is a full conversion of the current gas network to 100% hydrogen, to do so would require retrofits and replacements of some existing pipelines to manage the flow of gas. Alongside that, Xoserve would also need to adjust or even overhaul the current methodology for balancing, metering and billing hydrogen.

Furthermore, gas-powered appliances used for domestic or commercial purposes would need to be replaced to handle 100% hydrogen.

Xoserve is aware of the desperate need to upgrade the power grid to relieve the bottleneck effect on transmission. While that solution is potentially decades and billions of pounds away, repurposing existing gas pipelines may alleviate congestion in the meantime, and at a lower cost. To determine the extent of these challenges and the level of change required to overcome them, rigorous testing and trials of 100% hydrogen and hydrogen blending must be conducted.

By contrast, a major benefit of biomethane is that it can be fed directly into the existing gas infrastructure now, because it has the same chemical structure as natural gas. This approach offers the least resistance and cost to decarbonising natural gas, with little or no need to replace domestic appliances or gas networks. However, the biomethane value chain is less developed than renewable sources in the energy sector, so production is currently very low. The Anaerobic Digestion and Bioresources Association states that less than 1% of UK gas supply currently comes from biomethane.

Whatever the mix of the decarbonised energy system – biomethane, hydrogen or both gases – investment plans for the long-term operation of the renewable gas industry are crucial. This is to ensure the scale of production is available to meet national demand.

Storing renewable energy  
Over the past decade, coal-fired power has declined significantly in the UK, and wind power has taken its place. Despite this impressive and much-needed rise in renewables, natural gas produced 32% of the country’s electricity (from December 2022 to December 2023), a figure that has remained largely unchanged for almost 30 years. It is an inconvenient truth, but natural gas provides a consistent level of power generation compared to wind and solar, whose Achilles heel is the combination of environmental factors known as ‘dunkelflaute’ – a period with low winds and little sunlight.

Natural gas produced 32% of the UK’s electricity in 2023, a figure that has remained largely unchanged for almost 30 years. It’s an inconvenient truth, but natural gas provides a consistent level of power generation compared to wind and solar.

As well as for power generation, gas is also used for energy storage. Seasonal storage is vital in winter months, when heating demand can nearly double. Electric battery storage technology is making significant progress in combination with renewable power, but is nowhere near ready to support the entire nation’s energy consumption – and likely won’t be for the foreseeable future.

Hydrogen can be produced by surplus renewable electricity – which is hard to store – by diverting the surplus to power electrolysis, which splits water molecules into oxygen and hydrogen. The latter can be stored for future energy needs, rather than go to waste. A total of 6.5 TWh of wind power has been lost to curtailment since 2021. Since the start of 2023, wind curtailment payments have cost £590mn, adding £40 to the average consumer bill, according to Carbon Tracker.

Green gas policy and legislation  
The phasing out of fossil fuels is certainly necessary to meet net zero targets, but the final energy mix remains up for debate. Although natural gas is the primary gas used today to supply 23 million homes in the UK with heating and hot water, that network also offers low-carbon and zero emission alternatives to support the rise of renewables and an advanced power grid.

Before any decisions are made to decarbonise or decommission gas, energy leaders and policymakers must start to ask the difficult questions that come with moving away from natural gas. While we need to start taking action on building a new zero emission energy system, we also must ensure existing infrastructure is in place until the very last person has moved off natural gas.

• Further reading: ‘Repurposing infrastructure for the energy transition.’ Repurposing existing infrastructure such as pipelines to transport alternative fuels such as CO₂ or hydrogen can help accelerate the transition while reducing cost and waste. However, this is not without its challenges, explain the EI’s Technical Manager, CCUS, Eva Leinwather and Technical Officer, Energy Transition, Chimwemwe Kamwela.
• Find out how biogas could help Europe’s energy revolution.