New nuclear is too late and expensive for climate and energy crises

Greenland, the planet’s thermostat,[1] lost 105 billion tonnes of ice last year,[2] with sea ice the lowest in the 47-year satellite record.[3] The climate crisis is here and the choices we make now will determine the success or failure of our climate actions. Cost is key, but time is the most relevant variable – and time is running out.[4]

1. Time

It’s worth considering that global data analysis reveals construction of just one new nuclear station takes up to 17 years.[5] Nuclear power construction has an average over-run of 64%.[6] In comparison, global new solar is being deployed 100 times faster than new nuclear, and new wind 25 times faster. Utility-scale wind and solar take on average only two to five years from planning phase to operation, and rooftop solar PV projects are down to six months.[7]

At a time when so much looks grim, the renewable evolution holds out real hope. In 2025, more power was generated worldwide from renewable energy than from coal,[8] and 91% of new renewables are now cheaper than fossil fuels.[9] With all that implies for global energy policy and climate action, the UN[10] and IRENA[11] confirm that renewables have increased their lead over fossil and fissile fuels via economies of scale, technology innovation, and supply chain rollout.[12] The result is, wind and solar worldwide currently generate 70% more electricity than nuclear reactors[13] – whilst each year nuclear adds only as much net global power capacity as renewables add every two days. Nuclear is now facing the same challenges as fossil fuels; uncompetitive costs, stranded assets, a polluting legacy and unrivalled competition from renewables.

Can new nuclear generate power in time? Well, in 2025, installed nuclear capacity of 4.4 GW was 180 times lower than new solar and wind capacity, with the International Energy Agency (IEA) predicting 4,600 GW new renewable capacity by 2030 (current global nuclear capacity is 369 GW), meeting 90% of global electricity demand growth.

Over the past decade we’ve seen renewable electricity generation triple that of nuclear. By the end of this decade renewables will out-generate nuclear by a factor of between 5 to 7,[14] and as Chatham House concludes, renewables hold the key to EU energy security.[15]

Meanwhile, the benefits of SMRs (Small Modular Reactors) remain controversial,[16] with the Financial Times noting the technology is “already losing its glow”.[17] As no current SMR design under construction (much less operating),[18] SMRs remain a long way away – whilst producing more chemically and physically reactive waste.[19] Now comes another new nuclear vision; powering a brave new world of artificial intelligence (AI). Yet the IEA forecasts renewables will power data-centre growth 10-20 times over, with Bloomberg NEF predicting a 100-fold renewables expansion.[20] These numbers are compelling and carry meaning.

With new nuclear projects in Europe running years behind schedule and vastly over budget,[21] the former Chair of the U.S. Nuclear Regulatory Commission concludes there’s not enough time for nuclear innovation to make a realistic impact on the climate crisis.[22] In other words, the practical contribution of nuclear power to mitigate climate change seems profoundly limited.[23] Now more so, after the Intergovernmental PaneI on Climate Change (IPCC) reported that renewables are 10 times more effective at cutting CO2 emissions than nuclear.[24] The world has passed the point of no return,[25] and the direction of travel seems clear;[26] renewables are now the least cost and the quickest technologies for climate mitigation and new power generation.[27]

2. Cost

Perhaps astonishingly, the average nuclear build has a doubling cost overrun.[28] Whilst the marginal (fuel) costs of renewables are close to zero, nuclear fuel is extremely expensive. All this goes to explain why Lazard’s levelized cost of energy (LCOE)[29] for new nuclear plants is £109 per MWh, making it the most expensive generator – while unsubsidised solar and wind combined with energy storage (to ensure grid balancing) is significantly cheaper.[30] So it’s not hard to see why the UN now concludes that renewables are the default lowest-cost option for new power generation worldwide.[31]

In 2024, renewables investment totalled $2 trillion – more than double that of fossil fuel investment, and vastly more than nuclear,[32] with 582 GW renewables added to the global energy system. That’s 92.5% of all new power capacity added worldwide. No wonder the International Energy Agency (IEA) reports that global annual renewable capacity additions are set to rise to 935 GW each year by 2030 due to low generation costs compared to fossil and fissile fuels.[33]

Meanwhile, in the EU, wind and solar overtook fossil fuel power generation in 2025.[34] Solar alone grew by more than 20% in a single year, proving that clean power can scale faster than other technologies. So the challenge now is not generation, but how quickly grids, batteries and flexibility can be deployed.[35] With nuclear costs continuing to rise[36] and wind, solar, and battery storage becoming cheaper and more reliable,[37] it seems new nuclear has limited operational need and a poor business case.[38]

3. Climate Impact: Nuclear

Sea-levels are rising. With more frequent and destructive storm, storm surge, and flooding, extreme events become the norm and existing flood risk mitigation measures become obsolete.[39] This means that nuclear is on the front-line of climate change – and not in a good way.

Globally, 41% of all nuclear plants are coastal, and since sea-level rise climate risks to nuclear won’t be linear, this will significantly increase expense for nuclear construction, operation, waste management, and decommissioning. Inland nuclear plant will face wildfire risk, with episodic flooding alternating with low river-flow and raised water temperature[40] – significantly impacting on reactor cooling and discharge.[41]

Meanwhile, it’s concerning to note that the US Nuclear Regulatory Commission concludes that the majority of their nuclear sites have already experienced flooding hazard beyond their design-base. The US Army War College also reports that nuclear power facilities are at ‘high risk’ of temporary or permanent closure due to climate threats – with 60% of US nuclear capacity now vulnerable to sea-level rise, severe storms, and cooling water shortages.[42] 61% of the USA’s nuclear energy facility are expected to face water stress by 2030, potentially forcing them to reduce generation or shut down.[43] And in the UK, the Institute of Mechanical Engineers finds that coastal nuclear sites will need ‘considerable investment’ to try to protect them from rising sea levels, and even ‘relocation or abandonment’.[44]

It’s also worth recalling that nuclear avoids annually only 2-3% of total global GHG emissions – and considering the nuclear life-cycle (uranium mining, milling, conversion, enrichment, fuel fabrication, transport, construction and dismantling of the nuclear power plant, spent fuel processing and waste storage), nuclear produces significant CO2 emissions.[45]

4. Direction of travel – the renewables evolution

Solar and wind now lead new electricity generation.[46] Global solar and wind added 793 GW in 2025,[47] with solar meeting 61% of US electricity demand growth in 2025.[48] In the same year wind and solar were the first and second electricity-generating sources in Germany,[49] with the country’s share of renewable energy in the electricity grid stable at 55.9 %. Importantly, renewable energy surpassed lignite power generation for the first time there.[50]

In Europe, wind and solar generated more electricity than fossil fuel in 2025,[51] providing 30% of pan-EU power, demonstrating just how rapidly a renewables power system can move.[52] In the UK, the Royal Society concludes that renewables plus long-duration storage are not only feasible but will be cheaper than a system with a level of nuclear power.[53] Although solar has delivered the fastest energy transition in history, it’s set to be beaten by BESS (Battery Energy Storage Systems), with cumulative global installed capacity now at 690 GWh and rising.[54]

Unlike nuclear, the renewable evolution is here and now – on-time and cost effective.[55] It is entirely possible to mitigate climate impact and sustain a reliable power system by expanding renewable energy in all sectors, rapid growth and modernisation of the electricity grid, storage technology roll-out, faster interconnection, and using power far more effectively and efficiently via rational energy management.

The compelling economics of renewables unmask those of fossil and fissile fuels.[56] With all key international and national energy organisations and institutes agreeing that renewables will be doing the heavy lifting for the energy transition,[57] the future backbone of the global power supply system will be renewable, sustainable and cost-effective.[58] Nuclear is already too late and too costly for the climate and energy crises.

Full references and source material are available here.