Deaths Per Terawatt-Hour: The Data That Changes the Nuclear Debate
Coal kills 350 times more people per unit of electricity than nuclear. Even including Chernobyl and Fukushima, nuclear is among the safest energy sources ever deployed. Here's what the mortality data actually shows.
When people think about nuclear power, they think about Chernobyl. They think about Fukushima. They think about radiation, cancer, and catastrophe.
When people think about coal power, they don’t think about anything. Coal just… exists. Background noise. Unremarkable.
This perception gap is one of the most consequential failures of public understanding in energy policy. Because the data tells a completely different story.
Deaths per terawatt-hour of electricity produced:
- Coal: 24.6 deaths
- Oil: 18.4 deaths
- Gas: 2.8 deaths
- Nuclear: 0.07 deaths
- Wind: 0.04 deaths
- Solar: 0.02 deaths
Coal kills 350 times more people per unit of electricity than nuclear. Even including every death from Chernobyl, Fukushima, and every other nuclear incident in history.
How Do We Count Energy Deaths?
The figures above come from Our World in Data, synthesising research from Markandya & Wilkinson (2007) for fossil fuel deaths and Sovacool et al. (2016) for renewable accidents.
Deaths from energy production fall into two categories:
1. Direct Accidents
- Mining collapses
- Oil rig explosions
- Falls during construction
- Radiation exposure
- Dam failures
2. Air Pollution
- Particulate matter (PM2.5) from combustion
- Nitrogen oxides
- Sulphur dioxide
- Ground-level ozone
For fossil fuels, air pollution dominates. The vast majority of deaths attributed to coal, oil, and gas come not from accidents but from the chronic health impacts of breathing combustion products.
For nuclear and renewables, direct accidents are the primary (and much smaller) risk.
The Coal Death Toll
Coal’s death rate of 24.6 per TWh is actually conservative. The Our World in Data methodology uses European power stations with modern pollution controls. For global coal generation, particularly older plants in developing countries, death rates could be 4 to 9 times higher, potentially reaching 93-224 deaths per TWh.
What 24.6 deaths per TWh means in practice:
The UK generated approximately 2 TWh of electricity from coal in 2024, down from its historical peak. Applying the European death rate, that’s roughly 50 deaths. At global rates, potentially 200-450 deaths.
Historically, when coal provided the majority of UK electricity, the death toll was far higher. In 1990, UK coal generation exceeded 200 TWh, implying roughly 5,000 annual deaths from coal-fired power alone.
UK air pollution deaths:
Current estimates attribute approximately 2,500 premature deaths per year to UK power generation emissions. As coal has declined and been replaced by gas (which is cleaner but not clean), this figure has fallen. But it remains substantial.
Globally, fossil fuel combustion for power, transport, and industry causes approximately 5.1 million deaths annually, of which an estimated 3.6 million are from burning fossil fuels.
The Nuclear Death Toll: Including Chernobyl
Nuclear opponents often argue that death statistics exclude the “true toll” of accidents like Chernobyl. Let’s examine this claim.
Chernobyl (1986)
The worst nuclear accident in history. A flawed reactor design combined with operator error caused a steam explosion and fire that released radioactive material across Europe.
Immediate deaths: 28-31 people died from acute radiation syndrome in the weeks following the accident. These were primarily plant workers and firefighters.
Long-term deaths: This is where estimates diverge significantly:
- UNSCEAR (UN Scientific Committee): 62 confirmed deaths as of 2008, including later thyroid cancers
- WHO (2006): Projected up to 4,000 eventual cancer deaths among the 600,000 most heavily exposed people
- Greenpeace: Claims up to 93,000 cancer deaths (widely disputed by scientific community)
- Our World in Data synthesis: 300-500 total deaths as a reasonable mid-range estimate
Even taking the WHO’s upper estimate of 4,000 eventual deaths, Chernobyl remains a relatively small contributor to total energy mortality when measured against the electricity generated by nuclear power worldwide.
Fukushima (2011)
The second major nuclear accident, triggered by a tsunami that overwhelmed the plant’s defences.
Radiation deaths: Zero. No workers or public members died from radiation exposure. UNSCEAR concluded there will be no observable negative health effects for the public.
Evacuation-related deaths: 2,313 people died from the stress and disruption of evacuation, particularly elderly residents of care homes. These are real deaths caused by the nuclear accident, but they were caused by the response to radiation fear rather than radiation itself.
A 2013 study found that the evacuation may have caused more deaths than a more measured response would have, raising difficult questions about risk communication and proportionate response.
Total Nuclear Deaths: The Full Picture
Using official internationally-recognised statistics:
- Three Mile Island (1979): 0 deaths
- Chernobyl (1986): ~60 confirmed, up to 4,000 projected
- Fukushima (2011): 0 direct radiation deaths, ~2,300 evacuation-related
Adding smaller incidents over 70 years of nuclear power operation, the total death toll is in the low thousands, against cumulative nuclear generation of approximately 92,000 TWh worldwide (1965-2021).
This gives nuclear a death rate of roughly 0.03-0.07 deaths per TWh, depending on which Chernobyl estimate you use.
The Comparison That Matters
Let’s make this concrete.
To generate 1,000 TWh of electricity (roughly 3 years of UK electricity consumption):
| Source | Deaths per 1,000 TWh |
|---|---|
| Coal | 24,600 |
| Oil | 18,400 |
| Gas | 2,800 |
| Nuclear | 70 |
| Wind | 40 |
| Solar | 20 |
If Britain had generated its electricity from coal instead of nuclear over the past 50 years, the death toll would have been 350 times higher.
Conversely, if we had built more nuclear instead of burning gas, we would have saved approximately 2,700 lives per 1,000 TWh generated.
Why Don’t We See This?
If nuclear is so safe, why does public perception suggest otherwise?
1. Availability Bias
Chernobyl and Fukushima are vivid, memorable, heavily reported events. The 40,000 people who die from air pollution in the UK every year die invisibly, one at a time, their deaths attributed to heart disease, stroke, or lung cancer rather than to the power station emissions that contributed.
2. Dread Risk vs Statistical Risk
Humans are not rational calculators of risk. We fear unfamiliar, uncontrollable, catastrophic risks (nuclear meltdown) far more than familiar, distributed risks (air pollution). A single event killing 100 people feels worse than 100 separate events each killing one person, even though the toll is identical.
3. The Visible vs The Invisible
Radiation is invisible but detectable. We can measure it precisely, which paradoxically makes it feel more threatening. Air pollution is also invisible but less easily measured at the individual level. We can’t point a Geiger counter at ourselves and measure our accumulated particulate exposure.
4. Institutional Incentives
Anti-nuclear campaigns have been well-funded and persistent. No comparable campaign exists against coal air pollution, partly because the victims are dispersed and the cause-effect relationship is statistical rather than immediate.
What This Means for UK Energy Policy
Britain has effectively ended coal power, with the last coal plant closing in September 2024. This is unambiguously positive for public health.
But we have also presided over nuclear capacity declining from 100 TWh to 41 TWh over two decades. This capacity has been replaced primarily by gas (safer than coal, but still causing approximately 2.8 deaths per TWh) and imports (which export the pollution to other countries but don’t eliminate it).
The SMR programme represents an opportunity to rebuild nuclear capacity. Every TWh generated by nuclear instead of gas saves roughly 2.7 lives. Scale that across decades of generation and thousands of TWh, and the lives saved become substantial.
A concrete calculation:
If Britain’s proposed SMR fleet (potentially 8 units at Wylfa = 3.76 GW) operates at 90% capacity factor for 60 years:
- Annual generation: ~30 TWh
- Lifetime generation: ~1,800 TWh
- Deaths if generated by gas instead: ~5,000
- Deaths if generated by coal instead: ~44,000
- Deaths from nuclear: ~130
The safety case for nuclear is not abstract. It is thousands of lives.
The Air Pollution Blind Spot
UK government estimates attribute 28,000-36,000 premature deaths per year to air pollution. Not all of this is from power generation, transport is a major contributor, but energy production remains significant.
The economic cost is estimated at £6-62 billion annually, depending on methodology.
These deaths don’t make headlines. They don’t prompt government inquiries. They don’t generate protest movements. They’re simply… accepted. Background mortality. The price of modern life.
Meanwhile, a nuclear incident that kills no one (Fukushima) generates global coverage for years and prompts policy reversals across multiple countries. Germany’s decision to close its nuclear plants after Fukushima led to increased coal and gas generation and, by extension, increased air pollution deaths.
The numbers suggest this response was exactly backwards.
Objections and Responses
”But what about nuclear waste?”
Nuclear waste is a serious issue requiring long-term management. But it does not kill people at current exposure levels. High-level waste is contained, monitored, and stored. It is not dispersed into the atmosphere for millions of people to breathe.
Deaths per TWh from nuclear include all waste-related incidents. The figure remains 0.07.
”But what about weapons proliferation?”
Civilian nuclear power and nuclear weapons use related technologies, but the UK already possesses nuclear weapons. New civilian reactors don’t change our weapons capability.
The deaths-per-TWh calculation doesn’t include military uses of nuclear technology, which are an entirely separate policy domain.
”But renewables are even safer”
Correct. Wind (0.04) and solar (0.02) have lower death rates than nuclear (0.07). This is an argument for building all three, not for building renewables instead of nuclear.
The UK needs approximately 300 TWh of annual electricity generation, rising to 400-500 TWh as transport and heating electrify. There is no shortage of demand for safe, clean generation.
”The statistics are manipulated by the nuclear industry”
The primary source (Our World in Data) is an independent, non-profit research organisation. The underlying research is peer-reviewed and published. The methodology is transparent.
If anything, fossil fuel death estimates are conservative because they use European pollution controls as the baseline. Global rates are likely higher.
Conclusion: Follow the Data
Energy policy should be based on evidence, not intuition. The evidence is clear:
- Nuclear is among the safest energy sources ever deployed, with a death rate 350 times lower than coal
- Even including Chernobyl and Fukushima, nuclear’s safety record is exceptional
- Air pollution from fossil fuels kills millions globally and tens of thousands in the UK annually
- The perception gap between nuclear fear and fossil fuel acceptance costs lives
Britain has the opportunity to expand nuclear capacity through the SMR programme while maintaining its world-leading renewable deployment. This isn’t an either/or choice. We can build both.
The alternative, continuing to rely on gas for baseload power while importing 40% of our energy, means accepting thousands of preventable deaths per decade while paying £37 billion annually to foreign suppliers.
The data is clear. The question is whether we’ll follow it.
Key Sources
- Our World in Data: What are the safest and cleanest sources of energy?
- Our World in Data: Death rates from energy production per TWh
- Our World in Data: What was the death toll from Chernobyl and Fukushima?
- World Nuclear Association: Effects of Nuclear Accidents
- UCL: Fossil fuel air pollution responsible for 1 in 5 deaths worldwide
- BMJ: Air pollution from fossil fuel use accounts for over 5 million extra deaths a year
- UK Government: Health Matters - Air Pollution
- Our World in Data: The death of UK coal