The UK is increasingly seeing renewable energy generate a larger share of our electricity needs – that begs the question of when we could see the first gas-free day on the grid?
On April 1, the solar industry in the UK achieved a new milestone – generating 12.2 GW of our electricity needs. That was a record high as we began the new month with clear skies and plenty of sun. Coinciding with this, the UK’s grid recorded close to a record low output for gas-fired power stations.
In 2012, coal-fired generation provided almost 40% of the UK’s electricity needs, and yet in 2017, its share had fallen to just 7%. That was also the first year that the UK’s national grid recorded its first coal-free day – which coincidentally, also occurred in April. Little did we know that just seven years later, the UK would see a permanent removal of coal from its grid, as the final coal power station closed in September 2024.
That has led many to ask the question on whether natural gas is set to follow the same trajectory.
Could we see gas-free days in our near future?
While it had been the fossil fuel that helped us replace coal, natural gas is no longer the number one source of the UK’s electricity. It had held that title since 2015, and yet, in 2025, it was overtaken for the first time by wind power – which represented 29% of the country’s generation mix last year.
Natural gas’ days are unlikely to be numbered anytime soon, however. During the year it lost the title as the number one source of electricity, it still generated 26% of the UK’s electricity – and while renewables are making up a bigger share of electricity generation, we also can’t forget that by their very nature, they are still intermittent.
When natural gas hit its record low on April 1, it did so at around 2pm. That was buoyed by 10.6 GW of solar generation from the bright sunshine and nearly 8 GW of wind power. When the sun was fully set at 9pm, however, the need for gas generation came back. That’s because while wind power increased to 13.7 GW, there was no more solar on the grid, meaning we needed 3.4 GW of gas and 3.86 GW of nuclear power.
That brings us to the crux of the issue – to achieve a gas-free day, we would need a source of electricity that was consistent throughout all hours of the day, whether that’s enough wind power to cover all our electricity needs, or ample storage to collect excess renewable generation during periods of lower demand on the grid.
Would this be enough to achieve a gas-free day on the UK grid?
Take a scenario where renewables and energy storage can provide enough power for 24 hours, would we then be able to achieve a gas-free day? Well, no. That’s because CCGT power stations aren’t purely there to generate electricity for the grid, as for some stations, that’s simply a byproduct.
Phil Hewitt, Director at Montel Analytics – which is part of the Montel Group, explains, “Gas is likely to be a part of the GB fuel mix for a very long time. The reason for this is that there are CCGT plants whose economics are not driven by power prices and system services that are provided by CCGT stations.
“When there are a lot of renewables on the system, CCGT power stations are pushed out of the merit order because they are more expensive. This means that they switch off. However, there are two reasons why gas will be a feature of the mix going forwards:
- Some stations are not driven wholly by gas and carbon input prices and output power prices. These stations provide steam for industrial processes too so they generate power as a by-product of steam generation. In fact, in NESO’s plans for ‘clean power by 2030’ these stations are excluded from the modelling because they provide steam for industrial processes. Ultimately, these steam-raising operations can be replaced by other methods in the long term.
- Nuclear, biomass and gas stations provide inertia services to the system when they operate. Inertia can be provided by, among other things, synchronous condensers and synthetic inertia from batteries. These are not in at scale at the moment so gas will still need to be run to provide inertia.
“All of this means that we won’t get ‘gas free days’ any time soon because gas plants will be needed to provide steam and inertia. In two-three years’ time we could have a situation where no gas is being burned for inertia services but it will still be burned to generate steam.”
What does this all mean for our quest for a gas-free day?
National Grid ESO has previously said that it hopes to have enough measures in place this year to confidently run short periods with 100% inverter-based resources to help us lean on gas power plants for inertia for short periods – but this still won’t get us to a 24 hour period. Additionally, trials are already ongoing where for a few hours, only renewables, nuclear, and storage feed the grid, to test these systems.
It’s going to be a bigger issue long-term to deal with combined heat and power plants, as it’s currently a slow process to decarbonise heat. A major hospital that is currently receiving heat from a CHP plant isn’t going to switch to a low-carbon heating solution overnight, and therefore there will still be a little bit of gas generation on our grid as a byproduct.
Of course, long-term we’ll see many CHP plants converted to run on biogas or hydrogen to reduce their carbon emissions, or more buildings to leverage electric heat pumps as the decarbonisation of heat continues. But we shouldn’t forget our overall goal – to work towards net zero by 2050.
If we’re going to see a gas-free day, it’s likely to happen in the summer when there’s less demand for CHP. Just don’t expect it to happen in the next year or two as we don’t yet have the energy storage or renewable capacity for a 24-hour gas-free day.
Looking further ahead, with more offshore wind, solar, and batteries coming online, gas needed less for inertia, and significant progress being made on the decarbonisation of heat, then we might start to see 24 hour periods without gas. This likely won’t occur until around 2030, then after that date, expect it to become more frequent, just as we saw with coal.
But for now, don’t let perfect become the enemy of good. The fact we’re making progress and reducing the need for gas on the grid is a great sign. It means the carbon intensity of our grid is lowering every single year – in fact, since 2021, the carbon intensity of the electricity we’ve generated has decreased by 34%. Imperial College has even estimated that the UK will lead G7 nations when it comes to clean electricity generation. That’s a great position to be in, even if it means we won’t see a gas-free day for at least another five years.
