50 years that have changed Britain’s energy

The transformation of the electricity system from 1974 to today has been defined by the move away from coal and the decarbonisation of the grid. Between 2010 and 2020, the carbon intensity of the UK's electricity dropped 58%, from 450 grams per kilowatt hour (g/kWh) to 195 g/kWh.

"Government action has been a key driving force in the whole decarbonisation process," says Dr Staffell. "The long-term stability of the Climate Change Committee and their carbon budgets setting targets many years into the future, mean that even if there's short term variations in policies, there's always an overarching target for the future."

Coal power plants had been closing consistently following market privatisation, sometimes due to the plants reaching the end of their life span, but also because some had become uneconomical and uncompetitive as an electricity source. Legislation like the Large Combustion Plant Directive (LCPD), aimed at reducing carbon emissions throughout Europe, and new sulphur dioxide filtering system requirements also had an impact. For many older plants, it became more economical to close than bear the cost of these upgrades. Emissions trading schemes (ETS) and carbon pricing made coal power stations ever more expensive for the grid to buy electricity from compared to other sources.

Between 1990 and 2000, coal as a proportion of the UK's electricity production fell by more than half to 30%. In that same period, gas jumped from just 1.5% to 38% and by 2010 had become dominant, representing 46% of the country's energy production. It highlights how the market quickly shifted to gas as coal was gradually phased out. But over the coming decade, just as coal made way for gas, so renewable sources would come to make up more and more of our electricity mix.

In November 2012, the UK Energy Bill introduced "Contracts for Difference" - providing long-term contracts and a stable revenue stream for low-carbon-generating technologies. By guaranteeing revenue, this made wind and solar installations much more financially viable for companies to deliver.

It was the government's set Renewable Obligation (RO) scheme that underpinned the full conversion of Drax Power Station's first generating unit from coal to biomass in April 2013, following Drax's £20 million investment and 10 years of research and development. The second unit was then converted under the same RO scheme in 2014. Contracts for Difference (CfD) then enabled the power station to convert a third unit in 2016, while the final unit was then also converted through the RO scheme, but under a station cap in 2018.

The landmark Paris Agreement of 2015 committed countries around the world to reducing emissions and tackling climate change. This was followed by the UK's 2019 commitment to bring all greenhouse gas emissions to Net Zero by 2050.

The power of these legislations and incentives is clearest seen through the rise of wind as a major source of Britain's electricity. In Q1 2017, gas accounted for 40.9% of the electricity mix, while wind made up 13%, according to Electric Insights. By Q1 2024, this had shifted to 33.3% of the electricity mix coming from wind and 28.8% from gas. Coal, meanwhile, had dropped to just 1.4% in Q1 2024.

Balancing supply and demand in a renewable system

The increased level of intermittent renewables on the electricity system means balancing demand and supply is more complex today. Rather than several large power stations, the national grid operator now has to balance hundreds of different points of generation that are connected to the grid. Wind and solar power's dependence on weather also creates new challenges. If wind or sunlight levels suddenly drop, there's a need for what's known as dispatchable forms of power; ones that aren't dependent on weather conditions. While once that task would have fallen to fossil fuels like gas, today low carbon flexible forms of generation like biomass and energy storage come into play.

The country's electricity demand has also changed. It's no longer guaranteed that there will be high demand during the day and low demand at night. Now peaks and troughs in demand are less pronounced and can occur throughout 24 hours, as factors like remote working and new technologies shift electricity consumption. The challenge comes in matching periods of high demand with supply from intermittent renewables, while continuing to balance the grid.

Ancillary services, such as frequency control and inertia, were once taken for granted when most of the grid ran on large, spinning turbines, which provided these services automatically. Now, as wind and solar power becomes more prominent, electricity sources, like biomass or hydropower that still deliver stabilisation, have become increasingly important in balancing the system.

When Cruachan Power Station was built in the 1960s, it was designed to absorb excess power from nuclear plants to help balance the grid. Today it remains one of just four pumped storage hydro stations in the UK and continues to help stabilise electricity supply and deliver ancillary services to the grid. It does so by using its reversible turbines to absorb power from the grid, pumping water from Loch Awe up the mountainside to a reservoir. The water then acts like a battery and if the grid suddenly needs power, it can quickly generate as much as 440MW of electricity.

"Doing that has kept the grid in perfect balance over the last 60 years," says Kinnaird, FlexGen Assets Director at Drax.

In the 1970s, Cruachan operated a regular pattern of generating power to meet demand during the day and then absorbing excess power from nuclear stations at night. Today, it is excess levels of renewable wind power that the plant absorbs from the grid to keep electricity stable, storing it for when demand peaks. This capability allows Cruachan to support the UK's energy system as it increasingly switches to intermittent renewable power sources, and as the times of demand shift from the more predictable patterns of the past.

Today the UK is working towards a completely Net Zero electricity system by 2050, where there is no carbon released from power generation at all. This makes carbon neutral electricity, as well as increasing levels of energy storage, crucial to maintaining a secure, balanced system.

Building a secure, stable, Net Zero energy future

"Without doubt the biggest driver of change is the push to carbon neutrality. It's going to require a completely different way of looking at how plants operate and what kind of plants we have on the system," says Heppenstall. "It's going to involve tens of billions of pounds of investment. That will create huge opportunities, but it's also going to feel like a lot of change very quickly."

Carbon removals - technologies that can take CO₂ out of the atmosphere - will be crucial to achieving Net Zero in the power sector, as well as the wider economy. Building on systems like ETS (Emissions Trading System) and COP (Conference of the Parties) climate agreements, the carbon removals market could reach $100 billion globally per year between 2030 and 2035 and is widely seen as an essential factor in meeting the Paris Agreement goals and Net Zero ambitions.

In May 2018, Drax announced its plans to pilot the first (BECCS) project of its kind in Europe. BECCS technology combines power generation from sustainably sourced, renewable biomass with carbon capture, utilisation and storage (CCUS). It's a form of dispatchable power, which can support greater levels of wind and solar on the grid while capturing carbon emissions produced in the process and then storing it, permanently and safely, deep underground in geological formations specifically selected for this purposeIn the UK's case, carbon storage chiefly includes depleted oil and gas reservoirs in the North Sea, which are extensively mapped and have been used for CCS by Norwegian companies since the 1990s.

National Grid ESO's Future Energy Scenario's report makes it clear that deploying BECCS is There is no scenario under which BECCS is not required. It's another example of engineering and innovation designed to meet the needs of Britain's power system.

"Engineers have always solved the problems that the changing market has demanded of these plants," says Heppenstall. "And I'm confident they'll do the same with carbon capture."

Britain's energy system has almost completely transformed in the last 50 years, and whilst history doesn't repeat itself, it often rhymes. The same challenges of moving away from a coal-based system apply today as the transmissions system prepares for a renewable-focused future. The Russian invasion of Ukraine prompted a European-wide gas emergency evocative of the '70s oil crisis. New technology, like AI and electric vehicles, as well as global affairs, will also affect both how the grid operates and the demand upon it.

The Government's Clean Power 2030 Action Plan outlines how the UK will aim to achieve a clean power system by the end of the decade, whilst maintaining a secure and affordable energy supply.

The action plan envisions an electricity mix dominated by renewables such as wind and solar, which, following a rapid and widescale deployment of these sources, will provide the bulk of the UK's electricity generation. Since these sources are weather-dependent there will also be a critical role for low-carbon flexible and dispatchable generation such as batteries, long-duration electricity storage, carbon capture and storage, and biomass to ensure the safe, secure and reliable operation of the power system.

Alongside these actions the government also expects to see the creation of new industries and investments around the country, as well as the delivery of new electricity infrastructure.

It's a continuation of an electricity system that's always evolving. Through challenges and uncertain times, such as the COVID pandemic, Britain's energy system has proven secure and reliable, while continuing to decarbonise like few other countries.

Drax is still the UK's biggest power station. It has remained a crucial asset for over 50 years and has transitioned to meet changing needs and goals. Today, it is a bastion of energy security and stability. By pioneering BECCS, Drax is in position to accelerate the UK towards a secure, affordable zero-carbon future.

The cooling towers and chimneys that once signified the mighty coal power stations of the Trent Valley have been replaced by wind turbines on ocean horizons and solar panels in fields. But as the world strives towards a Net Zero future, the fundamental aim of delivering secure, affordable electricity endures.

To learn more about BECCS at Drax, click here.