Transforming the supergrid of the 1950s to a network built on an electrified future for generations to come

It was a privilege to be invited to speak at the annual Aurora Forum in Oxford this week, known for assembling the brightest and most creative minds in the UK energy industry, who’ve been instrumental in positioning the UK as a global leader in the transition to a green economy. I was hugely encouraged by the knowledge that all attendees were unified behind a common vision – to decarbonise our energy system, decrease our bills, and bolster our energy security.

And I’m really proud of the great progress we’ve made over the last decade. For example - we’ve reduced coal’s annual contribution to generation from 40% in 2013, to just 1% in 2023. In fact, just over half of the electricity used last year was from zero-carbon sources, of which almost 30% came from wind. And on a single day in December, wind accounted for a record 22GW of generation. So, it’s heartening to see just how far we’ve come, but I’m in no doubt, about the distance still to go to deliver the energy transition. And in no doubt about why it matters. The energy transition will reduce consumer bills in the long-term, it will increase our country’s energy security and resilience, and it will enable the decarbonisation of our economy and all the benefits that will bring.

Decarbonisation is not just good for the planet, it’s good for the economy too, delivering green jobs, and unlocking future economic growth in areas such as AI capability, data centres and gigafactories, to name but a few. And, of course, delivering the energy transition is critical to achieving the government’s net zero targets. And targets matter. They provide ambition and collective responsibility to achieve a goal. They highlight urgency and scale. But they can rarely be achieved without deep collaboration and a shared belief in the outcome. And we’ve seen this in action, as we come together to do what it takes to achieve 50GW of offshore wind by 2030, to decarbonise the power system by 2035, and ultimately to achieve net zero as a country by 2050. And there are many examples of how this collaboration and determination has led to new and better ways of delivery. 

Take the new Accelerated Strategic Transmission Investment (ASTI) framework for instance, made possible through collaboration with Government and Ofgem. Through this framework, National Grid is delivering 17 major infrastructure projects to help meet that offshore wind target. These projects, which we’re calling “The Great Grid Upgrade”, will connect more renewable energy to the system, more quickly than ever before. They are creating real green jobs right now, and will drive significant economic growth, whilst also decreasing consumers’ bills in the long-term and bolstering security of supply. And of course, just last week, the Electricity System Operator published its ‘Beyond 2030’ report, which sets out investment recommendations, to connect significant additional generation, and is an important step towards achieving that decarbonised power system.  

None of this will be easy to deliver - the scale and pace of delivery is at an unprecedented level. But we’re all united in our determination to achieve those targets. So, it would perhaps be understandable if those targets became our sole focus. If we saw 2050 as the ultimate goal. But, of course, time doesn’t stand still. And, just as today we’re looking to the future, so will the next generation tomorrow, and the one after that.  

The unprecedented investment in networks that we’re seeing today is very welcome and much needed. The grid is evolving incrementally, with significant upgrades already underway to deliver against the current expectations of the nation and indeed the planet. But what happens when those expectations change? When tomorrow’s needs are no longer the ones we identified today, and when the generations of tomorrow start looking to their future? Expanding the network incrementally inevitably means there will be limits on how much can be built, how quickly it can be built and where.

So, what are the ambitious, alternative options for the network beyond 2050 – for a future-ready, capacity-rich, net zero grid? For a grid that’s built not with the next 20 years in mind, but the next 60? These are some of the questions that we, at National Grid, have been asking. And the answers, in part at least, can be found in our history books. Because our engineering predecessors tackled a very similar problem back in the 1950s when Britain’s so-called ‘supergrid’ was born.  

By 1950, Britain’s original grid was at capacity. The National Grid had been formed in 1935 and had been designed as seven distinct networks serving different regions, not as a country-wide network for bulk electricity transmission. But demand for electricity was growing rapidly. British industry was driving significant demand, whilst domestic households were also turning to electricity as a cleaner alternative to gas for lighting and cooking. So just 15 years later, demand for electricity had risen ninefold, and major investment and expansion was needed. In particular, there was a need to transmit electricity from new coal power stations – mainly in the East Midlands and Yorkshire – to London and the southern counties, Manchester, Merseyside and Tyneside, where energy demand was increasing.  

Our talented forebears, designed an ingenious solution - a new high voltage transmission system to be built over, or superimposed on, the existing grid. It was nicknamed the ‘supergrid’. And you could say that the engineers that designed the supergrid were indeed superheroes, given the tremendous foresight they had, to build infrastructure which easily facilitated future upgrades. Powered by the new supergrid, Britain saw the growth of newer industries, such as vehicle manufacturing, electrical engineering, printing and publishing. Meanwhile, domestic appliances such as refrigerators and washing machines were transforming people’s homes and lives. Electricity was enabling a whole new world of opportunity.  

And, true to the vision of those supergrid engineers, the network was upgraded to a higher voltage during the 1960s, allowing it to carry more capacity, meeting the needs of the country in the swinging sixties, the headbanging seventies and beyond. That ambitious thinking, and the network that ensued, has served us incredibly well for the last 70 years. It was a capacity-rich network that grew with the country, underpinning economic growth and enabling the UK to become the global leader in connecting clean energy it is today. Every time the UK welcomed a new industry, embraced a new technology or developed a new approach to market design, the foresight of those 1950s engineers and the early investment in the network, meant the grid had the spare capacity to accommodate it.  

But today, just like in the 1950s, we find ourselves with a network that’s constrained. Demand on the grid is growing dramatically, and forecast to double by 2050 as heat, transport and industry continue to electrify. Future growth in foundational technologies like artificial intelligence and quantum computing will mean larger scale, energy-intensive computing infrastructure. Demand from commercial data centres will increase six-fold, just in the next ten years, and in homes, there will be an increasing shift towards heat pumps and electric vehicles. And so, as we consider the increasing constraints on the current ‘supergrid’, we’re once again at a pivotal moment. A moment in time that requires innovative thinking and bold actions to create a transmission network for tomorrow’s future.  

So, the real question is, are we reaching the limit of what an incremental approach can deliver? As we look towards the strategic spatial energy plan, do we also need to take a collective step back, and consider whether there are alternative long-term approaches to build a grid that is fit not just for the next 20 years, but for the next 60. One approach we think has potential is the construction of an ultra-high voltage onshore transmission network of up to 800 thousand volts. This would be superimposed on the existing supergrid, a super-supergrid if you like. This new grid would enable bulk power transfers around the country, with strategically located ultra-high capacity substations, supporting the connection of big energy sources to big demand centres via the new network. This model consolidates infrastructure by connecting the larger capacity hubs in the places they’re most needed. It is both a strategic and proactive approach instead of today’s incremental, tactical and reactive one.  

We would transition from a network of hundreds of individual connection projects dotted around the country, all requiring their own approval and infrastructure, to major capacity hubs where investment is directed to where it’s needed. And crucially, these new high-capacity substations would have spare connection points for new customers, providing faster and more flexible connections. This new concept would build on existing infrastructure, superimposing an ultra-fast backbone on top of the current transmission network. It would allow more efficient construction and a better value solution for consumers from targeted and more co-ordinated investment, and would also bolster the system’s resilience. Not only would it allow us to meet the emerging needs of the network today, for example, moving vast volumes of offshore wind power from the North Sea to demand centres in southern England, but it would be a capacity-rich network designed for growth. 

That spare network capacity would open up opportunities for economic growth that could otherwise be constrained by a transmission network that is essentially reaching capacity. This is not instead of the infrastructure we’re delivering today and investments we’re making right now, this is in addition. It doesn’t change the need for “The Great Grid Upgrade”. It certainly doesn’t change the need for immediate, urgent reform to the connections process, which we’re working tirelessly with Ofgem, the ESO and industry to enable. All of these, and so much more, remain critical, as does a continued clear-eyed focus on the targets we’re all so familiar with.  

But what I’ve set out is a vision for the future and how we can transform our electricity network to make the country’s economic growth ambitions possible. And the time is right to think beyond tomorrow. The time is right to consider, as the superhero engineers did in the 1950s, how we create the next supergrid for not just the next 20 years, but the next 60. To design a network that believes in opportunity, is rooted in growth, and built on the vision of a prosperous electrified future for generations to come. And, as with every step that has come before it, this vision too will rely on partnerships, collaboration and joint endeavour.