August 31, 2022 • 4 min read

Nuclear energy: what you need to know

In this article

The low-carbon characteristics of nuclear power make it a critical energy source for a sustainable world

The purpose of a nuclear reactor is to produce heat to generate steam. Unlike in a coal- or gas-fired station, in a nuclear plant, the energy to produce this steam comes from uranium. Inside a nuclear reactor, a process called nuclear fission splits uranium atoms. This process generates heat, which turns water into steam, generating electricity in a turbine generator without emitting any CO2. The by-product of generating nuclear power from uranium fuel is nuclear waste. Safely storing this material is an important consideration in nuclear energy projects, as the spent nuclear fuel needs to be cooled down over a long period of time and eventually permanently stored at deep geological repositories or, in some countries, reprocessed into different fue

Imagine if we could find an abundant, carbon-free form of energy to safely power our homes and businesses every hour of every day.

This energy source already exists. Right now, nuclear power makes a significant contribution to electricity generation, providing about 11 percent of the global electricity supply. Around the world, there are 439 nuclear power reactors in operation in 32 countries, with a combined capacity of 390 GW (IAEA).

Nuclear energy is often overlooked in discussions about decarbonization and sustainability. However, it’s currently the second largest low-carbon energy source in the world after hydro. And it supplies clean energy to millions of homes across five continents.

What is nuclear energy?

Nuclear energy comes from converting the energy in a chemical element called uranium into electricity or heat. It emerged as a new approach to meet growing electricity demand in the mid-20th century, and the technology continues to evolve today.

Nuclear energy is an alternative to electricity generated from fossil fuels. The output of a nuclear power station is very consistent, with similar characteristics to coal- and gas-fired power stations. However, nuclear power plants produce no greenhouse gas emissions during operation.

Nuclear technologies are operational around the world, including in the Americas, Europe, Asia, and Africa. The USA currently produces the most nuclear energy. However, nearly all the current growth in nuclear power capacity comes from China and Russia.

How does nuclear energy work?

The purpose of a nuclear reactor is to produce heat to generate steam. Unlike in a coal- or gas-fired station, in a nuclear plant, the energy to produce this steam comes from uranium. Inside a nuclear reactor, a process called nuclear fission splits uranium atoms. This process generates heat, which turns water into steam, generating electricity in a turbine generator without emitting any CO2.

The by-product of generating nuclear power from uranium fuel is nuclear waste. Safely storing this material is an important consideration in nuclear energy projects, as the spent nuclear fuel needs to be cooled down over a long period of time and eventually permanently stored at deep geological repositories or, in some countries, reprocessed into different fuels or products.

Is nuclear energy sustainable?

Nuclear energy is a sustainable energy source. But like all forms of energy, there are environmental considerations for every project. Uranium comes from mining. This means some CO2 emissions are almost certainly attributable to uranium supply chains. Power generators must also consider the transport and long-term storage of nuclear waste in their environmental assessments.

However, generating electricity at a nuclear power station is carbon-free. Nuclear power is therefore key to decarbonization goals for businesses, heavy industry, and the wider world. And its contribution is about more than just clean electricity. Nuclear power can play a critical role in stabilizing energy supply during the transition to more renewables, battery storage, and hydrogen.

Nuclear energy can also help produce clean hydrogen. The electrolysis process requires electricity to separate hydrogen and oxygen from water. When this electricity comes from a nuclear power station, it’s called pink hydrogen. Nuclear power is perfectly suited to this application because electrolyzers require a consistent electricity supply to be efficient.

The future of nuclear energy

The IEA forecasts global nuclear power capacity needs to grow by around 20 GW per year to achieve net-zero emissions by 2050. But in 2021, the world added just 5.3 GW of new global nuclear power capacity, and construction started on another 7 GW. Meanwhile, power generators retired 7.7 GW of nuclear power globally. Currently, 52 new nuclear reactors are under construction globally.

Two factors are key to the future of nuclear energy: building new nuclear power capacity and extending the life of existing nuclear power stations through maintenance, component replacement, and license renewal. Both factors will play an important role in meeting the demand for low-carbon electricity in sustainable energy systems.

Over time, the global approach to nuclear energy is also likely to shift to a greater number of smaller nuclear reactors. Although SMRs are currently still in development and their economics are not yet fully proven, many countries have a growing public interest and government support.

The benefits of SMR-based distributed generation and microgrids with custom-tailored cogeneration capabilities – including heat, hydrogen, and desalination – are wide-reaching. Most SMRs have inherent safety and waste management advantages, which could also ease licensing and improve social acceptance. They may also be attractive to countries with no experience with nuclear power, especially those with smaller and less robust electricity grids, due to the overall lower total cost and their simplicity of operation.

Remote off-grid communities, industrial facilities, and traditional utilities – that are expected to facilitate the integration of growing wind and solar capacity into the electricity system – are likely to benefit from the deployment of SMRs.

It takes time to design, license, build and commission any nuclear power plant. That means power generators need to start planning new nuclear plants today, so they’re operational when the planet, and humanity, need them the most.

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