Our journey through the arithmetic of sustainable energy has established an enormous deficit. Britain’s future electrified lifestyle demands 48 kWh/d per person of clean electricity (120 GW nationally). Domestic renewable resources max out at approximately 18 kWh/d per person due to a “social ceiling” imposed by land-use constraints. Solar imports offer a potential 20 kWh/d per person, but this introduces major geopolitical dependencies.
This shortfall demands investigation into other major power sources: nuclear fission, nuclear fusion, and “clean” fossil fuels.
I. The Fission Equation: Britain’s Dense Power Option
Nuclear fission power operates fundamentally differently from renewable sources. It works by breaking apart heavy atoms, releasing the energy stored within their nuclei. This process is extraordinarily dense in power output.
1. Power Density of Nuclear Fission
The power per unit land area occupied by a nuclear power station is consistently remarkable. The Sizewell B nuclear power station, a single pressurized water reactor, generates 1.2 GW of electrical power from a site occupying only 0.25 km² (plus a surrounding exclusion zone).
Nuclear power density: 1000 W/m²—vs. 2 W/m² for wind farms
This means that the power density of a nuclear power station is about 1000 W per square metre of site. This is 500 times the land-use efficiency of wind power and more than 20 times that of solar power.
2. Britain’s Nuclear Legacy and Potential
The UK currently has 15 nuclear reactors, many of which are approaching the end of their operational lives. To understand nuclear’s role in the sustainable future, we must quantify the land requirements.
To generate 10 GW of new-build nuclear power (a significant contribution of 10 kWh/d per person), the total required land area would be less than 10 km² (approximately 10 one-kilometre squares). This area could easily fit within Britain’s existing licensed nuclear sites.
| Scenario | Capacity | Land Area |
|---|---|---|
| Current UK nuclear | 9 GW | ~9 km² |
| Proposed new-build | 10 GW | ~10 km² |
| To replace all coal | 20 GW | ~20 km² |
3. Addressing Nuclear Objections: A Measured Response
Legitimate public concern about nuclear power often centers on several key issues, all of which deserve careful examination.
Safety: Modern reactor designs incorporate passive safety features that prevent runaway reactions. The argument that an accident would render large portions of a country “uninhabitable” is countered by real-world examples. Sizable populations live in Chernobyl’s exclusion zone, and residents returned to Nagasaki and Hiroshima. The evacuated area around Fukushima is small (300 km²) compared to the scale of modern nations and can be remediated.
Waste: The volume of high-level nuclear waste produced per person is extraordinarily small: 0.84 ml per year (about the size of a sugar cube) for all of Britain’s past nuclear electricity generation. This contrasts sharply with the waste from fossil fuels, which spreads throughout the atmosphere.
Proliferation: The risk that civilian nuclear technology provides a pathway to nuclear weapons exists, but it is a political and international relations challenge, not one of physics or energy economics. Existing nuclear states and the international regulatory framework (IAEA) provide oversight.
Cost: The historical cost of nuclear power per unit energy is comparable to, or often lower than, its alternatives. The perception of high cost often comes from the first-of-a-kind nature of new reactor designs and from the extensive regulatory and safety reviews required, which are not applied equally to fossil fuel plants whose environmental costs are externalized.
II. Nuclear Fusion: The Distant Promise
Nuclear fusion works by joining together light atoms (typically hydrogen isotopes like deuterium and tritium), releasing the energy that binds them. It is the process that powers the sun.
1. The Appeal of Fusion
Fusion offers the potential for virtually limitless fuel supply (deuterium can be extracted from seawater) and significantly less long-lived radioactive waste compared to fission. The fuel cycle is also more resistant to proliferation.
2. The Engineering Challenge: ITER and Beyond
After decades of research, controlled nuclear fusion remains an immense engineering challenge. The international ITER project, under construction in France, aims to demonstrate a sustained fusion reaction that produces more energy than it consumes. Its first significant plasma experiments are not expected until the 2030s.
Fusion timeline: Commercial reactors not expected before 2045–2050
Fusion power stations operate with a low power density per unit land area (as the plant requires complex cooling and shielding), so their footprint will be comparable to current fission stations.
Given this long timeline, fusion cannot be counted upon for inclusion in energy plans targeting the next two or three decades. However, it remains a crucial area for continued research and investment, offering a potential long-term solution to humanity’s energy needs.
III. “Clean” Fossil Fuels: Carbon Capture
The idea of “clean coal” or “clean gas” relies on capturing the carbon dioxide emissions from power stations and sequestering them underground before they enter the atmosphere. This technology is known as Carbon Capture and Storage (CCS).
1. The Efficiency Penalty
Capturing and compressing CO₂ requires substantial energy, reducing the overall efficiency of the power plant.
- Energy penalty: Capturing and compressing the CO₂ requires between 25% to 40% of the power station’s output.
- Net effect: A power station equipped with CCS will burn significantly more fuel (around 30–50% more) to deliver the same net electrical output.
2. The Scale of Storage
Even if CCS technology becomes economically viable, the sheer volume of CO₂ that needs to be stored is staggering.
CO₂ storage need: 25 Mt/year for just 5 clean gas power stations
If Britain built five large “clean gas” power stations, each capturing and storing its CO₂, these plants would need to store approximately 25 million tonnes of CO₂ per year.
To put this in perspective, this volume is several times larger than the current total output of all UK oil and gas operations. Suitable geological formations (depleted oil and gas fields, saline aquifers) must be found, assessed for long-term integrity, and developed. The pipelines and infrastructure required would be immense.
3. The Verdict on “Clean” Fossil Fuels
CCS remains unproven at the scale required to make a significant dent in emissions.
- Technical readiness: As of this writing, there are no large-scale commercial power stations operating with full CCS.
- Cost uncertainty: The true cost of electricity from a CCS-equipped plant is highly uncertain but is expected to be substantially higher than from conventional fossil or nuclear plants.
- Continued extraction: Any plan relying heavily on CCS still requires the continued extraction and burning of fossil fuels, perpetuating the associated geopolitical and environmental risks of mining and drilling.
CCS should be considered a potential bridging technology, allowing some continued use of fossil fuel assets while other clean sources are scaled up, but not as a cornerstone of a truly sustainable energy future.
IV. The Role of Dense Power Sources
Examining nuclear fission and fusion alongside “clean” fossil fuels illuminates the core trade-offs in energy planning.
| Source | Power Density | CO₂ Emissions | Fuel Security | Availability |
|---|---|---|---|---|
| Nuclear Fission | ~1000 W/m² | Zero | High (uranium) | Now |
| Nuclear Fusion | ~500 W/m² | Zero | Very High | 2045+ |
| Clean Coal/Gas | ~300 W/m² | Low (CCS) | Moderate | Potentially 2030s |
Nuclear fission stands out as the only currently available, proven, high-density, low-carbon power source capable of providing continuous baseload electricity independent of weather and foreign policy. Its role in any realistic sustainable energy plan for Britain is therefore significant and likely essential.