The consensus is that a 1.4oC average global temperature rise is due to a 50% increase in atmospheric carbon dioxide levels emitted from combustion since the beginning of the industrial revolution. The consequences of this are well known in terms of more extreme seasonal weather effects that disrupt the natural world by way of weather instability, such as increased flooding, drought, disease, famine, to name but a few. Effects have intensified more recently due in particular, to accellerated emissions over the past 40 years [1, 2].
Energy consumption (electricity, heat and transport) is responsible for over 70% of our greenhouse gas emissions, so it makes sense to focus on decarbonising electric grids and our heating and transportation systems [3]. Individual lifestyle changes to promote better energy efficiency, eating less meat and planting trees are compromises that help somewhat, but are not enough to realistically slow, stop or reverse carbon emissions; we need a reliable low-carbon energy supply.
While this is not an anti-renewables post, there must be caution against advocating them as a sole solution to our predicament. Firstly, wind turbines and solar panels are land-intensive; and material intensive for the energy they produce. In addition, hydro-power, solar and wind are relatively destructive with a high ecological impact due to the low amount of energy they deliver, from mining to waste disposal. Unpredictability and intermittency of a weather dependent supply cannot be solved by batteries, which store energy for no more than hours. Intermittent sources are backed by methane-intensive gas power, which is expensively managed to fit with peak demand times.
Excess ramping of gas turbines is inefficient and can generate higher emissions due to start-stop idling as opposed to running at a steady rate.
See the comparison of a selection of energy sources below. Limitations of any renewable energy, whether tidal /wave / solar / wind / geothermal are due to natural laws, resulting in low availability and siting issues.
Notes:
Energy density in kWh/kg from Nature, Energy and Society: A Scientific Study of the Options Facing Civilisation Today
Safety is deaths per TWh (inverted) from ourworldindata.org
Life Span is the maximum life expectancy of a technology (approx). Dependent on design, feasibility, grid system, political factors
Reliability (Capacity factor) and lifecycle greenhouse gas emissions (grams of carbon dioxide equivalent per k Wh), are from UNECE Report Life Cycle Assessment of Electricity Generation Options (2022)
Public support Public support figures are derived from the YouGov 2024 Polls
Biomass is considered ‘renewable’ in the UK, yet it primarily derives from burning imported woodchips at Yorkshire’s Drax power plant, as well as energy-from-waste schemes.
Burning wood releases carbon dioxide which contributes to the greenhouse effect.
Coal is a reliable source of ‘baseload’ electricity. Burning coal is considered a ‘chemical’ reaction which captures the fast energy of electrons from carbon-based molecules.
As a fossil fuel, burning this generates carbon dioxide, responsible for anthropogenic global warming, as well as releasing particulate matter such as nitrous oxides which can create smog and potentially contribute to respiratory problems in built up regions.
Gas is a generally reliable and flexible energy source, and like coal, it is carbon based, and combines with air to release carbon dioxide.
Carbon dioxide stays in the atmosphere 300-1000 years and the excess from burning gas and coal results in an imbalance which is negatively impacting ecosystems and life within them as we know it.
It is the aim to reduce our dependency on such energy sources.
Methane is a large component of gas, and has more warming potential than carbon dioxide.
Geothermal energy harnesses the natural heat of rocks in the ground.
It is potentially feasible in some geologically unstable areas with significant tectonic activity in the crust.
Geothermal plants exist in California, Italy and Iceland.
Hydropower / hydroelectric power is one of the oldest and largest sources of renewable energy, which takes the flow of moving water released from behind a thick concrete dam to generate electricity.
Nuclear Energy can harness extremely high vibrational energy of the nuclear forces to generate energy with very little fuel and very little waste. Initial nuclear plants were designed for making plutonium and uranium but current nuclear plants under construction/planned in the UK are for civillian purposes only. Nuclear energy is safe contrary to public perception.
‘Spent’ fuel is cooled for 2-3 decades in a deep pool of water. Then remotely operated equipment dismantle the fuel elements to be dry stored inside casks for a few hundred years. Very little waste is produced due to the extremely high energy density of the fuel.
Solar photovoltaics are silicon semiconductors that absorb sunlight and create an electric current. Photovoltaics have been popularised due to subsidies.
A 300 Watt PV panel is 10% reliable in the UK, meaning on average, it would generate enough energy to power a 30 Watt lightbulb continuously (if the requisite battery storage were theoretically
feasible).
Wind-generated power is a variable resource, and the amount of electricity produced at any given point in time by a plant will depend on wind speeds, air density and turbine characteristics. Installed capacity is fixed, but supply and demand are variable characteristics that don’t necessarily match as shown:
The reality is that when countries close nuclear plants in favour of solar and wind farms, they are invariably replaced by gas or coal [4].
For a realistic low carbon energy policy it is sensible to highlight the relevance of an important scientific property of the source of energy considered, which is called ‘energy density’. Fission of a uranium/thorium atom creates in the order of a million times more energy than the chemical energy released from breaking Carbon-Carbon bonds [5]. So a kilogram of fuel can last a person’s lifetime. In fact, all eco-credentials of nuclear power stem from this high energy density: lower land and material footprint, cleaner air and less waste produced at all stages.
Nuclear waste is managed very cautiously in line with stringent regulations specified by the Office for Nuclear Regulation and there is a public radioactive waste inventory which details waste arising from all nuclear-licensed sites in the UK [7]. Anyone concerned that waste could remain fissionable is invited to read on about a natural reactor, called Oklo, which fissioned underground 2 billion years ago in Gabon. The waste products barely migrated, let alone re-started a fission reaction in more than 50 million lifetimes. Also, obtaining fissile material is less of an issue for terrorists, than the difficulty of creating such a weapon.
Nature, Energy and Society: A Scientific Study of the Options Facing Civilisation Today by Professor Wade Allison
For those who trust the data, the problem for nuclear energy is one of perception. Misinformation about nuclear energy stems from cold war political propaganda and also the persistent use of the Linear No Threshold (LNT) model which was unreliably adopted in the 1950s on the assumption that no dose of radiation is the only safe level. The flaws of the model are that:
- We have been exposed to radiation since life first evolved on earth. High-sensitivity radiation detectors show that it’s impossible to completely escape it, and
- plenty of evidence determines that cells can and do repair following low-level radiation exposure
The word ‘mutation’, which relates to cancer in cell biology, has fired imaginations ever since, and inspired some exciting but inaccurate stories for TV shows and Hollywood films. The Scientists for Accurate Radiation Information (SARI) is a concerted international professional exposure of LNT model [8]. SARI formed after the tsunami in Japan in 2011 caused an accidental release at Fukushima Daiichi and local people were unnecessarily relocated and psychologically stressed by false fears, effectively suffering what is known as the ‘nocebo’ effect, the opposite of a placebo. ‘Nocebo’ describes a situation where a negative outcome occurs due to a belief that the intervention will cause harm.
With respect to accident risk assessments; people feel less fearful about a situation if they feel in control, or the hazard has been normalised (e.g. car accidents). The nuclear fear example often cited is that people don’t want another Chernobyl. Yet, apart from the 28 staff and emergency workers killed from direct impact or exposure, even this – the worst nuclear accident – caused, for the most part, an exposure to radiation levels comparable to, or a few times higher than annual levels of natural background. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has reviewed all the published research on the incident and determined that at present, fewer than 28 documented, plus 15 statistical thyroid cancer deaths are likely to be attributable to increased exposure to radiation [9].
Anecdotal stories from industrial accidents are upsetting, but why those involving the nuclear industry are perceived to be worse than those from other industries is illogical. For example, the Piper Alpha oil rig explosion which also occurred in the eighties, and killed 167 men is rarely brought up in discussions of safety, suggesting a widespread lack of understanding of facts.
As evidenced on the cards above, nuclear is safest. Nothing is completely risk free, so we should stop ignoring real risks while requiring perfection elsewhere.
Scientists include nuclear energy in all pathways to net zero in their Intergovernmental Panel on Climate Change’s 2018 Special Report (15) on Global Warming of 1.5oC [10]. The UK’s current plans only focus on replacing those nuclear facilities due to retire over the coming decade. But we should think bigger by working on full scale deployment of nuclear energy to the grid alongside changes to the wider transport and heating infrastructure.
Climate change and fossil fuels kill millions per year whereas nuclear energy does not.