Blog: Is nuclear power an essential part of the net zero energy mix?

Nuclear is one energy source set to play a significant role in our low carbon future. It has already been recognised by the UK government as pivotal to its energy security strategy, with the Chancellor announcing in March 2023 the launch of Great British Nuclear: a government body tasked with providing up to one quarter (24GW) of UK electricity generation by 2050 through nuclear power. He also announced that nuclear energy would be classified as ‘environmentally sustainable’ in the UK’s green taxonomy, providing it with  the same access to investment incentives as renewable energy such as wind and solar power.

But while the wheels are already in motion to select and implement the small modular reactor (SMR) technologies that could help the UK put this low-carbon energy source to good use, it is undeniable that the production of nuclear energy comes with some limitations and concerns. Here we take a look at how nuclear energy works, explore how the nuclear fission technology used today might be replaced with nuclear fusion during the decades ahead, and uncover some of the primary advantages and disadvantages of bolstering our energy capacity with nuclear power,

Nuclear energy today

According to the World Nuclear Association, the UK currently generates around 15% of its electricity from 6.5 GW of nuclear capacity. While most of the UK’s existing nuclear power plants are coming to the end of their operational life, and the construction of new nuclear plants has been plagued with delays, Hinkley Point C in Somerset is now expected to come online before 2031. Great British Nuclear is also pushing ahead with its plans for a series of smaller reactors built to one agreed design, in an effort to build nuclear capacity more quickly and effectively.

Nuclear fission vs nuclear fusion: what are the differences?

All of today’s nuclear energy capacity is created through a process called fission. Considered in the simplest terms, the nuclear fission process involves using a neutron to split one large atom into two smaller atoms. As the atoms split, further neutrons are released, starting a chain reaction. The fission process releases a large amount of heat energy that can be used to generate steam and turn a turbine - to generate electricity. 

Unlike nuclear fission, which works by splitting atoms, nuclear fusion works by combining smaller atoms into one heavier one. Fusion creates huge amounts of energy; up to four times more than fission. However, this is the same process that powers our sun and stars, so it is understandably difficult to control and scale. It requires extremely high pressure, high temperature conditions that are difficult to replicate on Earth.

The advantages and disadvantages of nuclear power

The fission process used to create nuclear power today might seem like an incredibly complex way to create steam and achieve the same result as burning a fuel like wood, coal or gas, but it does have one major advantage: it does not release any carbon dioxide into the atmosphere. Nor does it release air pollution in the form of fine particles, sulphur dioxide, nitrogen dioxide, nitrates or phosphates. For this reason, nuclear power is often hailed as a green energy source and a vital part of the net zero puzzle.

This classification of nuclear energy as ‘environmentally sustainable’ has created some confusion and controversy; raising the question, ‘is nuclear energy renewable?’. The answer in real terms is no. While a high percentage of the spent uranium (U-235) fuel source used for nuclear energy can be reused or recycled (up to 96% according to nuclear energy group Orano), uranium reserves are finite and expected to be depleted by the end of the century. The radioactive waste created during the fission process is an additional disadvantage associated with nuclear power. Disposing of this waste is both difficult and expensive; it may pose a risk to life and the environment for many thousands of years to come.

There are certainly many considerations to balance when it comes to building our dependence on nuclear energy as a part of our net zero energy mix. If we are to decarbonise electricity generation by 2035, and if electricity demand doubles by 2050 as predicted, nuclear energy will be essential to providing a valuable extra layer of energy self-sufficiency and security for the UK. It can also provide reliable baseload power to help keep the grid balanced as we shift to renewable sources like wind and solar, that are intermittent by nature. Conversely, there is no question that climate action groups like Greenpeace will continue to challenge the role of nuclear power in a truly sustainable and Earth conscious energy system.

The future of nuclear power

If scientists are able to successfully scale nuclear fusion processes up to commercial levels during this century, it may change the way we all think about nuclear energy. Fusion has the potential to produce infinite quantities of clean energy without carbon emissions or long lived radio-active waste. Its by-products are helium and low amounts of tritium: a radio-active substance with a short half-life. Unlike fission, which has an unfortunate history of large-scale disasters associated with its use, fusion is also considered to be inherently safe. It does not create a chain reaction and must take place at high temperatures and within magnetic containment; if either condition is lost, the energy production would automatically stop.

It’s easy to see why fusion is considered by some to be ‘the holy grail of clean energy’, but thanks to delays and rising costs we are still some way from being able to use it to power our homes and businesses. The Hinkley Point C power plant, for instance, has been delayed for completion until 2031, with costs rising to £35bn. While nuclear power offers great potential, the UK is simply not ready for it at scale.  In the interim, finding safe, proportionate ways to incorporate different available energy sources in the mix seems to be our most sensible option.

In contrast, gas is a tried and trusted energy source with an established infrastructure network. Indeed, when it comes to gas production, the UK currently imports over 510TWh on average, giving net imports of 425TWh a year, to meet our annual demand of 850TWh. The gas industry itself is innovative and resilient, and while transitioning to a low-carbon gas network will be complex, we have no doubt that the sector will prove its resilience; to adapt and succeed.

Watch out for our next decarbonisation blog as we explore more renewable energy sources.

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