The UK’s energy transition is often described in terms of momentum, says John Haw, CEO of Fidelity Energy, but the true picture is far more complex.
Renewables are expanding. Coal has all but disappeared from the system. Offshore wind continues to scale. On the surface, the direction of travel looks clear.
But the latest UK Energy Trends data reveals a more complicated and uncomfortable reality.
Renewable electricity generation reached record levels in the third quarter of 2025, supplying the largest share of power on the UK grid. At the same time, overall fossil fuel dependency across the energy system increased to 72.6 per cent, up from 72.1 per cent a year earlier.
That tension sits at the heart of the energy debate. Clean generation is rising, yet fossil fuels are still carrying more of the system than many people realise.
Understanding why matters, because it explains why volatility, pricing shocks and uncertainty continue to affect households, businesses and public services even as renewable capacity grows.
One reason is that electricity generation does not exist in isolation. When nuclear output fell to a record quarterly low due to refuelling schedules and outages, gas stepped in to fill the gap.
Gas use for electricity generation rose by nearly 10 per cent year on year, offsetting gains elsewhere in the system.
This is not a failure of renewables. It is a reminder that energy systems are built around balancing and resilience, not just capacity. When low-carbon sources fluctuate or go offline, flexible fossil generation is still doing the heavy lifting.
Until storage, demand management and system flexibility scale alongside renewables, gas will continue to act as the shock absorber.
In other words, the system is getting cleaner, but not yet calmer.
At the same time, overall energy consumption is falling. Total primary energy use declined by more than three per cent year on year, and final energy consumption fell even further.
In theory, lower demand should ease pressure on prices. In practice, volatility persists.
That is because volatility is not driven solely by how much energy is used. It is driven by how the system responds under stress.
Electricity imports remain historically high. Gas supply chains remain exposed to infrastructure outages and global market dynamics. Pricing mechanisms continue to pass short-term movements through to end users, even when underlying demand is weak.
For organisations that rely on energy every day, this creates a disconnect. Costs do not simply track consumption. They track exposure. And exposure is shaped by contract structures, pricing models, peak demand and system design.
This is where the conversation about clean energy often loses focus. Megawatts installed matter.
But so do the rules that govern how energy is bought, sold and priced once it enters the system. Without reform, clean power risks inheriting the same volatility that characterised the fossil-fuel era.
That risk is compounded when success is measured by installation rather than performance.
Public money is increasingly tied to clean energy upgrades, Haw adds, but accountability for outcomes remains weak.
Too often, progress is judged by what is installed, rather than by whether those interventions actually reduce volatility, lower costs or improve resilience once buildings are in operation.
Without granular monitoring and ongoing visibility, he says, it becomes difficult to know whether energy upgrades are delivering the stability and savings they promise, or whether volatility is simply being shifted elsewhere in the system.
The data points to a system that is cleaner, but not yet secure. Renewables now supply the majority of electricity, yet fossil fuels still dominate total energy use.
Demand is falling, yet risk remains high. Gas continues to play a critical stabilising role, even as the UK seeks to reduce reliance on it.
If the goal of the transition is genuine energy security, he says, success should be measured not only by carbon intensity, but by predictability and resilience.
That means long-term pricing frameworks, better demand management, and clearer accountability for outcomes — particularly for those least able to absorb shocks.
The next phase of the transition is not just about building more clean power, it is about building a system that translates that power into stability.
Until pricing and system design catch up with generation, volatility will continue to sit beneath the surface, regardless of how green the grid becomes.
