Phillip Blond is Director of ResPublica.

The Paris Climate conference in 2015 gave us some stark conclusions and some even blunter goals. To limit the rise in global mean temperatures to 2° Celsius, we will need to almost completely decarbonise the entire global power system by mid-century. Since the consequences of not doing so are so dangerous and are such a threat at a planetary scale to human and non-human life, this is one of the foremost human goals of the next 30 years. Simply put, this goal is not achievable by renewables alone; only by using nuclear power in combination with other clean tech such as hydro can we do this.

A good example of this is Germany. Renewables have increased to about 30 per cent of its domestic power mix and about 50 per cent of its installed capacity, but its carbon production hasn’t fallen, it’s risen. That’s because to compensate for the intermittency of renewables, the amount of coal in Germany’s energy mix has also risen to about 30 per cent. In fact, seven out of the ten worst CO2 producing power plants in Europe are in Germany, and they burn coal. Given that Germany has closed down or is phasing out its zero-emission nuclear power plants, this situation will only worsen to such an extent that any current and future carbon gains made by its hugely impressive wind and solar developments will be wholly wiped out by its new post-nuclear reliance on coal.

So, if we all do what Germany has done – massively invest in renewables but cancel or phase out nuclear – we will never hit any decarbonisation targets and the world will pay the price. To paraphrase from a Nuclear Energy Agency paper of 2015, cumulatively nearly 60 gigatonnes of CO2 have been avoided globally since 1971 thanks to nuclear power, and global annual CO2 emissions from electricity supply would rise by 12 per cent a year if we simply negated nuclear and replaced it with our current energy mix. So if we want a green future, we must also go nuclear.

Transitioning from the global to the local, Britain is also committed, thankfully, to the Paris climate goals. In the UK, coal will drop out of the power system by 2025, leaving gas as our most CO2-producing fuel. If Dieter Helm’s recent energy cost review is adopted (as it should be), we will have a universal carbon price across the whole economy and a carbon price at the border to cut down on both carbon production and consumption. Done well, this will start to price out gas just as we have priced out coal. This should take us to the clean energy mix we need.

As mentioned above, the main reason we need nuclear is that renewables cannot as yet offer us security of supply. Quite simply in energy generation terms post-gas and coal, we cannot and could not cope with a week without wind and/or a week without sun – weather conditions that are not unusual for the British Isles. And given that we cannot store enough power to run the whole country for a week at grid scale in any future battery network that anyone can envisage, even the combination of renewables and enhanced battery storage will not secure our supply.

In our ResPublica report Expanding Horizons, published today, we argue as a result of all the above that committing Britain to a new nuclear programme is vital to securing a clean energy mix, and a role as a world-leader in low-carbon, secure energy production.

The UK is home to the world’s oldest nuclear energy programme. In 1956, Her Majesty the Queen opened the world’s first commercial scale nuclear power station at Windscale and Calder Hall (now Sellafield) in Cumbria. We led the world in harnessing the power that nuclear technology unlocked and, in doing so, we were able to keep homes warm and lit without dependence on foreign imports. We exported the technology to other countries, such as Italy and Japan, and were world-leading in many aspects of the field. Today that tradition is sadly atrophied. The nuclear programme that embodied the virtues of ingenuity, invention, and self-reliance that have long been part of Britain’s national story, has been allowed to wither and we needed to import foreign expertise and industry to replace our rapidly ageing capacity for nuclear generation.

A pipeline of new projects – from Hinkley Point C in Somerset, to Wylfa Newydd on Anglesey, to Bradwell in Essex, to Moorside, back where it all began in Cumbria – stand ready to restart Britain’s nuclear programme. Each of them can make a crucial contribution to the UK’s future energy mix, and together they would form a significant revitalisation of the sector in the UK. Each will create many thousands of jobs, cultivate new high-level skills in our economy that underpin the Government’s industrial strategy, and help to ensure and guarantee Britain’s energy security long into an uncertain future. They would also help to retrain our own workers in this industry and build home nation capacity. There has of course been much criticism of the costs of Hinkley, but at least they fall on the contractors for now. They don’t get a penny until they produce power.

However, the real focus on nuclear should be around innovation in the sector. The industry reaction to Three Mile Island and Chernobyl has been to innovate largely around the safety of light water reactors (hugely increasing their cost), but often not challenging the basic design itself.

This is understandable as, given the uncertainly of new technology, at least the basic light water design is proven and the environment won’t wait for us. Remember, we only have 30 years to decarbonise. We do need to persist with proven nuclear models while forcing innovation into the more basic design elements of the plant. In part, the industry has innovated around this design with, for example, Hitachi’s ABWR (built and refined four times over in Japan) being introduced to the UK along with the more traditional PWR forms like Hinkley C and Sizewell B. Since costs will fall with a series build it is important to test the various forms of proven nuclear technology to ascertain what works best.

In terms of future innovation, the industry is basically and problematically split into two parts. The first is the so-called small modular reactors, which are designed to be smaller and reliant on mass manufacture rather than bespoke engineering, and open thereby to multiple production, all of which the industry argues will make them less costly.

The second is alternative, or Generation IV, nuclear, which has abandoned the PWR-based model and cools and heats with molten salt, lead or gas rather than water. Speculatively, the gains from these alternate nuclear models are vast, they are inherently safer, and (though calculations are theoretical) the resulting electricity is potentially much less expensive – perhaps even half the price of Hinkley Point’s power. Furthermore, some designs can even store electricity and so function as nuclear batteries. Unfortunately, Britain seems to be losing the global race for alternative nuclear to Canada and the US, when ultimately that is the race which we might most need to win. But we are talking about a nuclear eco-system here and each aspect will support the other parts of the system. To be frank, we need it all: the conventional and the innovative help secure the generation platform for the wholly new.

The new nuclear programme alone will not solve all of the UK’s energy and trade challenges, but it should be understood as more than simply one part of the energy mix. Investment in new nuclear also gives Britain a secure platform for innovation, exciting new opportunities for high-value, high-skills trade and a set of deep relationships with powerful global trading partners.

We have an opportunity to demonstrate that Britain can – and will – lead the world once again on nuclear power, in close co-operation with our allies in Europe, Japan, the US and further afield. If we take this opportunity we will be showing that this country, post-Brexit, means to be a global player with strong national purpose and ambition when it comes to energy that is both clean and green.