UK storage’s role in the National Grid pathways

The rubber is finally hitting the road as far as the UK’s energy transition is concerned. That much is evident from the closure of Britain’s last coal plant, the planned shutdown of the Grangemouth oil refinery in 2025 and progress towards delivering 10% of the country’s 2030 low-carbon hydrogen target at Teesside.

Such measures are in the nick of time, according to the latest Future Energy Scenarios study published by National Grid ESO, the electricity system operator for Great Britain.

“We’re less than 30 years away from the net zero deadline, which isn’t long when you consider investment cycles for gas networks, electricity transmission lines and domestic heating systems,” says the operator.

But more importantly, says Claire Dykta, National Grid ESO’s director of strategy and policy, in a foreword to the report: “The evolving dynamics of the energy system call for decisive action within the next two years to deliver the fundamental changes required to achieve a fair, affordable, sustainable and secure clean energy system.”

In a sign of this growing need for action, the Future Energy Scenarios study, which has been published roughly every two years since 2011, no longer looks at ‘scenarios’ in 2024. Instead, it outlines three potential pathways to achieve net zero, plus a ‘counterfactual’ pathway that misses the UK’s decarbonisation target.

The three pathways that National Grid ESO contemplates in its report are:

• A ‘holistic transition’ where net zero is met through a mix of electrification and low-carbon hydrogen, plus strong consumer engagement around smart devices, electric vehicles and demand shifting. 
• An ‘electric engagement’ pathway where most of demand is electrified and efficiencies are achieved through technologies such as heat pumps and electric vehicles. 
• A ‘hydrogen evolution’ pathway where clean hydrogen gets used widely for industry, heavy goods transport and heat, for example replacing gas boilers. 

All three pathways require carbon dioxide to be captured and stored for the UK to meet its net zero target. This could be achieved through a mix of direct air capture plus bioenergy with carbon capture and storage, the Future Energy Scenarios report says.

The pathways—and the counterfactual, which does not include carbon drawdowns through direct air capture—also all require the bulk of energy generation to come from renewable sources such as wind and solar. The exact amount varies from less than three fifths in the counterfactual to about four fifths in holistic transition.

Relying so much on intermittent renewable energy sources means a lot of flexibility needs to be built into the system. In the counterfactual, much of this comes from natural gas. In the hydrogen evolution pathway, flexibility is provided by hydrogen-powered gas plants. 

Yet all pathways also imply a major buildout of batteries, with the holistic transition—arguably the most likely pathway since it does not require potentially unrealistic commitments to either hydrogen or nuclear-based electrification—having the greatest dependence on electrical energy storage. 

The numbers involved are staggering compared to the 4.7 GW of battery capacity installed across the UK in 2023, even ignoring the storage potential of vehicle-to-grid technology. The holistic transition would demand 35.6 GW of battery storage by 2050. 

Another eye-catching feature of the pathways is that most of the battery storage capacity needs to be installed by the end of this decade. “The holistic transition pathway requires 27 GW of battery energy storage by the end of 2029,” notes the energy storage data provider Modo Energy. 

“This would require 23 GW of battery energy storage to come online in the next five years.”

In rough numbers, this translates to around a gigawatt of installations every quarter—which is an order of magnitude higher than what is happening on the ground. 

The target is also 5 GW more than the ESO predicts in its five-year forecast, Modo Energy adds, “which falls short of both the holistic transition and electric engagement pathways.” 

Essentially, says Modo Energy, the only one of National Grid ESO’s proposed net zero pathways that could be met with the current rate of battery installations is the hydrogen evolution pathway—but that will require 2.7 GW of hydrogen-powered energy generation to be installed by 2031, from none whatsoever today. 

Furthermore, says Modo Energy, the rate of battery plant installations has slowed in recent months rather than speeding up. “The first half of 2024 saw the lowest new operational capacity since 2022, totaling 370 MW, due to delayed projects,” Modo Energy says. 

“Battery providers have attributed some recent delays to connection delays at the DNO [distribution network operator] level, commissioning testing issues and equipment issues. Factoring these delays into Modo Energy’s five-year forecast for battery buildout means battery capacity in 2029 would be 20 GW.” 

This would miss all National Grid ESO’s net zero pathways, Modo Energy says. And it is not just battery storage that is off course. Based on National Grid ESO’s own five-year forecast, the UK is not on track to meet any of the net zero pathway greenhouse gas emissions reduction curves either.

“This is why the next couple of years are so important,” says Dane Wilkins, Pacific Green’s managing director for Europe. 

“Without serious work to unblock connection queues after the National Energy System Operator finalises its grid reform, rapid modernisation and digitisation of National Grid’s Balancing Mechanism, and a streamlined planning process, the UK’s battery buildout will fall too far behind to ever let the country achieve its climate goals.”

The good news is that there is still just about enough time to get things right—and the new government has got off to a strong start in terms of prioritising electricity infrastructure planning among its top commitments. But for targets to stay in sight, all stakeholders in the UK energy transition must play to their strengths. 

One of the eight keys for success outlined by Claire Dykta in a Modo Energy podcast is to have the supply chain and skills for the UK to achieve its energy transition goals. 

This is an area where Pacific Green has demonstrated capabilities after developing the Richborough Energy Park project at speed and on budget despite the lingering threat of COVID in China. 

Based on this, we can confidently say that if government can deliver the right investment signals then we—and other developers—will be willing and able to scale rapidly. 

National Grid ESO’s pathways provide a credible yet sobering assessment of what it will take to get to net zero—now we need an equally credible route for commercial delivery.