I have been a climate activist for well over a decade. Sixteen years ago I was arrested once for protesting about tar sands and again for protesting about coal. In 2018 I was one of the main spokespeople for Extinction Rebellion UK and founder of its print newspaper The Hourglass, and in 2015 I authored an evidence-based book on green parenting.

I try to ignore ad hominem attacks, since they only show that the attacker has a weak argument. But I want to respond to the latest: 'Why is support for nuclear power noisiest just as its failures become most clear?', an article here on openDemocracy by Andrew Stirling and Phil Johnstone.

Since I started talking about nuclear positively, I have been accused of being an industry 'shill'. But I have never taken money from the nuclear industry. I've said publicly that if the industry promoted its product better then I wouldn't have to do the job for it. It has a clean product that requires little land compared with the alternatives, and doesn't cause air pollution or climate change.

The industry also provides green jobs that are unionised - supported by GMB Union, Prospect and others - unlike most renewable enterprises.

Conversely, renewables have such good branding that most people don't even consider their environmental impact.

It was realising all of this that made me want to advocate for nuclear energy.

There is scientific consensus that we need nuclear power to address climate change. Nuclear energy is included in all of the IPCC's pathways for decarbonisation in its landmark 1.5°C report.

The nuclear waste myth

When I was anti-nuclear, my main concerns were safety and waste. I later learned that nuclear power is only slightly less safe than wind, hydro power and solar. More importantly, it is vastly safer than any fossil energy, once you factor in air pollution as well as accidents.

Almost everything I believed about waste turned out to be wrong. While many people think of Sellafield in regards to waste management, this is actually a nuclear weapons facility, where spent fuel is also reprocessed. Spent fuel is well managed and has never harmed anyone. In fact, nuclear waste was stored in dry storage casks (thick blocks of concrete) at the Daiichi nuclear power plant in Fukushima, Japan, and they were completely undamaged despite being hit by a tsunami and earthquake. This is a standard waste management approach, and the casks were intended to be stored on site for decades, to be reprocessed at a later date.

Waste management methods vary per country. Spent fuel can be recycled, which France has been doing for years. Finland is building a deep geological disposal facility to bury spent fuel, where it will be safely stored for as long as is needed. Mistakes have been made with inadequate waste disposal, and certainly where this has happened those countries should ensure that management is adequate. This is a political issue rather than a technical one.

On the other hand, toxic waste from solar panels is not well managed: there is currently no way to recycle them, which means that they end up in landfill sites where they leach toxic chemicals. This hazardous waste needs a solution, but doesn't seem to concern many environmentalists. Meanwhile, fossil fuel waste is being stored in the Earth's atmosphere.

Price tag

Stirling and Johnstone use a metric called "levelised cost of energy assessment" (LCOE) to argue that renewables are the cheapest of all energy sources, over the lifetime of an individual generation plant. However, LCOE is not appropriate for assessing the cost of weather-dependent resources like wind and solar. An in-depth study of the levelised cost of wind power found that "windfarms are not cost effective when a certain output must be guaranteed as major opportunity costs are introduced."

According to Dieter Helm, an energy economist at the University of Oxford, "The more renewables are added to the grid, the more backup must be built as well, even if much of it sits idle much of the time." Opposition to nuclear has driven the cost up.

Stirling and Johnstone claim that "nuclear power diverts resources and attention away from more effective strategies, increasing costs to consumers and taxpayers". Yet in 2019, France's electricity, 71% of which came from nuclear energy, cost just 59% of that in Germany, which had been shutting down nuclear power since 2011 and is still struggling to phase out coal. What's more, Germany's solar and wind farms will have to be rebuilt every 15 to 25 years. Nuclear power plants can last from 40 to 80 years or more.

Build them faster

Is nuclear power "slower, less effective and more expensive at tackling climate disruption", as Stirling and Johnstone state? Slower in the UK, yes, but let's look more widely. A 2016 analysis found that of the 441 reactors then in operation around the world, 18 were completed in just three years: 12 in Japan, three in the US, two in Russia and one in Switzerland. The mean construction time was 7.5 years. The UK could decarbonise quickly, if it really wanted to.

Standardisation has been shown to reduce build time and cost, which means using the same engineers to build the same reactors one after another. France built over 50 reactors in the 1960s and 70s and they still enjoy that clean energy today. France has even been exporting clean nuclear energy to Germany, which has decided to close all of its own nuclear power stations. As a result of this, Germany is missing climate targets despite pouring trillions of euros into renewable technologies. It is still the EU's largest coal power country; former chancellor Angela Merkel admitted to approving the Nord Stream 2 gas pipeline due to the need for gas to replace nuclear. German Green MEP Sven Giegold has said that Germany will need additional gas capacity in order to "stabilise" renewable power on the electricity grid.

Green-on-green war

Many people first became anti-nuclear out of a fear of nuclear weapons, and that's understandable - it would be odd not to fear weapons of such scale. But there is no correlation between weapons and energy. For example South Korea doesn't have nuclear weapons, but it is one of the world's largest nuclear power producers, whereas North Korea has nuclear weapons but no nuclear energy programme.

Stirling and Johnstone argue that nuclear power is "seriously under-challenged", when actually groups like Greenpeace, WWF, Avaaz, Clean Air Alliance, most Green parties, and even the German government have been lobbying against it for decades. Greenpeace has staged many protests against nuclear energy, and WWF has argued that the world needs renewables but not nuclear. Remarkably, WWF admits that renewables need a backup energy source, and that they'd prefer that to be gas.

The authors of the piece state that "media attention is repeatedly given to emphatic claims that relatively few people died directly during nuclear catastrophes." But such claims are simply the truth - only one death has been linked to the Fukushima Daiichi nuclear power plant meltdown, and even that number is debated. In fact more people died due to the unnecessary, panicked evacuation of the area after the meltdown.

The worst nuclear disaster that has occurred was in Chernobyl, Ukraine, and was due to the combination of human error and an old reactor design that did not have a containment structure - a concrete and steel dome over the reactor itself designed to keep radiation inside the plant in the event of such an accident. All reactors of this type have since been upgraded to ensure these additional safety measures, and no new ones are being built. Estimates of the numbers of deaths from Chernobyl vary widely: 4,000 according to the World Health Organisation, 16,000 according to another paper.

All methods of energy production carry a toll, and nuclear is still one of the safer options. Hydropower is clean, but disrupts ecosystems and can be extremely dangerous: the worst ever energy-generation disaster was the Banqiao dam collapse in China in 1975, which killed between 171,000 and 230,000 people. Few people seem to fear hydropower the way they do nuclear power. Nevertheless the focus should really be on eliminating the big killer: fossil fuels.

Academic battles

The authors point to a paper in Nature Energy by Benjamin Sovacool, Stirling himself and others which claims that "nuclear programmes do not tend to correlate with generally lower carbon emissions. The building of renewables does." However, Nature Energy has just published a critical response which concludes: "there are serious limitations in the Sovacool et al. analysis, which call into question the policy implications advanced by the authors." The same journal has included a further response from Sovacool and colleagues defending their work.

There appears to be a bias in favour of the renewables-only argument in the peer-review process for journals. In 2015 Stanford University professor Mark Jacobson published a study in the Proceedings of the National Academy of Sciences arguing that the world can be powered by 100% renewable technology. This was debunked in 2017 because it used "invalid modelling tools, contains modelling errors, and made implausible and inadequately supported assumptions". Jacobson then tried (and failed) to sue the scientists who flagged up these problems. Nevertheless, his paper is treated as a bible for renewables-only advocates. He later published a similar study in the journal Joule.

There is no one-size-fits all energy scenario for every country. The data on the countries that have largely decarbonised demonstrate that it has only ever been achieved with a combination of nuclear energy, hydropower and a little wind and solar in addition. That's not my opinion, it's just arithmetic. Are "renewables displaying such massively improving performance worldwide", as Stirling and Johnstone state? Yes, in some countries they are, but they are not managing it long-term without a back-up power source - known as baseload power - for when it's not windy or sunny. Not anywhere in the world.

The arguments made by Stirling and Johnstone against nuclear power today are the same arguments I was making a decade ago, and I was wrong. I was pro-renewables-only too, writing and rallying in favour of them and arguing that better battery storage and the energy transition were just around the corner. I changed my mind about nuclear energy because the scientific consensus compelled me to. We can't keep making the same bad arguments today, while the Global South slowly becomes uninhabitable due to climate change, just because spent fuel has a PR problem.

As for other groups setting up shop in the wake of my nuclear advocacy, I'm going to take some credit for that, and I'm proud to do so. Although cults may hold disdain for those who question their convictions, thankfully we also live in a world where many people appreciate it when someone changes their mind based on reason. Perhaps even one day I'll be able to tell my children that some of my climate action actually worked. If I save one nuclear reactor from being prematurely shut down, I'll be able to calculate the carbon emissions I've saved, and even the lives. That's my real motive.

Stirling and Johnstone assert that "free thinking should always be welcomed". I agree, but only when it is supported by facts.

Johnstone and Stirling tell openDemocracy: "We have had prior sight only of selected details of Ms Lights's critique of our [openDemocracy] article - and these are gravely misleading. For instance, contrary to Ms Lights's implication, even the 'critical' article she cites actually confirms our argument that nuclear is less associated with lower carbon emissions than renewables are.

"Beyond this, there is much in her critique we have not yet seen and this brief comment affords too little space to address much more. This in itself reflects the sad wider mismatch in public and media debate that our article documents, between PR rhetoric on nuclear power and opportunities for open, rigorous response.

"Of course, many complexities and uncertainties do (as we say) leave space for legitimately contrasting positions, for and against. But it is again deeply misleading for Ms Lights to present partisan personal preferences as unambiguously driven by 'scientific consensus'. Science, the climate and democracy all deserve better."

From openDemocracy