Key Takeaways
- Nuclear energy is a scalable, reliable, carbon-neutral, and pollution-free energy source that could be used to rapidly decarbonize the electricity sector and reach net zero by 2050.
- Nuclear energy has a small land footprint and very high reliability factor.
- Continued innovation in advanced nuclear technology may help to reduce nuclear plant construction costs, improve fuel cycle sustainability, and decrease waste volumes.
In 2016, 195 countries signed the Paris Agreement, a commitment to mitigate climate change by reducing greenhouse gas emissions. Many governments and utilities have committed to net-zero emissions by 2050 as a result, and there is a collective interest in identifying scaleable and carbon-neutral solutions to generate reliable energy for society at large.
Nuclear energy generates large amounts of electricity without releasing carbon emissions. It can be beneficial for the environment because it can replace highly carbon emitting fuels with greater than 90% reliability and availability.
At COP28 in 2023, 22 countries including the U.S., Canada, Japan, the U.K., and France committed to work towards tripling nuclear energy capacity by 2050 from 2020 levels, citing the key role nuclear energy is expected to play in achieving decarbonization goals.
However, challenges remain that today’s innovators are working to overcome, including high startup costs and long-lived radioactive waste.
In this article, we’ll take a deeper dive into the environmental benefits and remaining technical challenges to widespread adoption of nuclear energy.as
In This Article
Environmental Assessment of Energy Sources
Greenhouse gasses such as carbon dioxide, methane, and nitrogen oxides contribute to trapping heat in the atmosphere, leading to the global warming effect that is associated with climate change.
Currently, the leading source of greenhouse gas emissions is from burning fossil fuels for electricity, heat, and transportation. While currently necessary to maintain modern society, fossil fuels are not ideal long-term energy generation sources because of their emissions.
The question remains: what energy source can be used in the long-term with minimal effects on the climate or society? Broadly speaking, technologies with low greenhouse gas emissions contribute less to global warming and can be viewed as more environmentally sustainable.
Carbon-neutral technologies, like solar and nuclear power, have an especially beneficial effect when they replace carbon-intensive sources such as fossil fuels. Replacement is one strategy that electric utilities are using to decarbonize.
But emissions aren’t the only environmental impact that needs to be considered in energy technologies. Even a carbon-neutral energy source could have a negative environmental impact if it leads to pollution or other forms of environmental damage.
Determining the environmental consequences of different technologies requires an evaluation of the benefits and costs these technologies can impart. Nuclear energy produces no carbon emissions from operation, but can create emissions in the process of mining raw materials like uranium or in producing concrete for the structures.
Similarly, solar photovoltaic cells produce no carbon emissions from operation, but can create emissions in the process of extracting raw materials like silicon.
All technologies come with tradeoffs, so determining what matters most is a complicated process that varies by state, province, or country.
Different types of energy have different environmental advantages
- Renewable energy is energy produced from renewable sources, or sources that will not diminish over human timescales, such as solar or wind power. Certainly the sun will eventually burn out, at which point solar and wind power will no longer function — but given the long timespan until then, these sources are considered to be effectively limitless.
- Clean energy refers to energy that does not release greenhouse gas emissions or pollution in significant quantities. Nuclear energy is an example of a clean energy source that is not renewable, since it releases no emissions during power production but depends on a finite, nonrenewable supply of uranium fuel.
Evaluating the commercialization of energy types
In addition to their emissions, energy technologies can be evaluated based on a few other criteria to determine their benefits in tomorrow’s energy landscape and how they can help reach net-zero emissions by 2050:
- Reliability: A reliable source of energy is one that can consistently generate power to meet the demand and needs of the grid. Nuclear power operates over 90% of the time, including during severe weather, making it reliable.
- Scalability: A scalable source of energy is one that could reasonably be developed to supply the very large amounts of energy that are needed to power cities, countries, and the world. Solar photovoltaic cells have seen a rapid decrease in deployment costs, improving their scalability with time.
- Flexibility: An energy source’s flexibility refers to how well it can adapt to quick changes in demand. Natural gas plants, and in particular, natural gas peaking plants, are considered some of the most flexible sources of energy because they can be turned on very quickly to generate large quantities of electricity to meet demand.
- Profitability and Economics: Economics is one of the most important driving factors in energy transitions. If an energy source is too expensive, it is less likely to be implemented.
What is the Environmental Impact of Nuclear Energy?
While none of today’s energy sources could be considered perfect, stakeholders can use the criteria above to determine how they value attributes of various energy sources. Nuclear energy has many favorable attributes when considering the impact it will have on the environment.
Nuclear power does not produce direct carbon dioxide emissions
Nuclear power is produced by splitting atoms in a process called fission. Fission is a completely carbon-neutral process, and during operation, nuclear plants do not release any carbon dioxide or greenhouse gasses.
There is significant debate, however, as to how much carbon is released in other aspects of the nuclear fuel cycle. There is little agreement on how much greenhouse gasses are released when a plant is constructed or decommissioned, for example.
Emissions from nuclear energy are significantly lower than fossil fuels
Fully measuring and quantifying emissions from a nuclear plant requires a life-cycle analysis.
This involves tallying the total amount of emissions related to every aspect of plant construction, operation, and decommissioning, from preparing the land to completing decommissioning, and including things like materials, transportation, and waste disposal.
Estimates of life-cycle emissions of nuclear energy range from 2 tonsCO2 per GWh to about 130 tonsCO2 per GWh. The average estimates (29 tonsCO2 per GWh) suggest that nuclear energy releases about as much CO2 emissions-per-unit energy as wind (26 tonsCO2 per GWh) and about ⅓ as much as solar (85 tonsCO2 per GWh).
Although precisely determining life-cycle emissions is challenging, it seems reasonable to conclude that CO2 emissions from nuclear, wind, and solar photovoltaic are comparable.
Importantly, all estimates agree that emissions from nuclear energy are significantly lower than fossil fuels — which range from 499 tonsCO2 per GWh for natural gas to 1,054 tonsCO2 per GWh for brown coal.
Nuclear, wind, and solar power can all help reach the Paris Agreement climate goals through decarbonization of the electricity sector.
Nuclear energy protects air quality
Nuclear plants operate with zero emissions, and the only gas that rises from a nuclear plant’s cooling towers is steam.
In addition to releasing no major greenhouse gasses during operation, nuclear plants don’t release any air pollution in the form of particulate matter, aerosols, and toxic chemicals.
In the U.S., the Nuclear Energy Institute estimates that the country’s nuclear plants saved 471 MTCO2 in 2020 — equal to the emissions of about 100 million cars — and that closing the Vermont Yankee Nuclear Power Station led to a 650,000 TCO2 increase in just the first two months.
This demonstrates the positive environmental and human health impacts of decarbonization and the social and environmental costs of an energy landscape with less clean power than today.
Nuclear energy has a small land footprint
A single nuclear reactor, built with today’s designs, generates about 1 GW of electricity with a plant area slightly larger than a square mile. It produces this energy at least 90% of the time.
In order to generate the same amount of electricity as a nuclear plant, wind power requires a land area up to 360 times larger, and a solar plant would require up to 75 times more land to reach the same electric output.
Considering the enormous amounts of land that would be required to scale wind and solar energy, nuclear is an attractive clean energy source due to its small, highly efficient land footprint.
Nuclear energy produces minimal waste
Environmental groups often express concerns about nuclear waste. Used nuclear fuel contains a handful of isotopes that will remain radioactive for hundreds of thousands of years, such as plutonium.
However, used nuclear fuel is relatively small in volume, making it more manageable to deal with. If all the used fuel from 60 years of nuclear power generation in the U.S. were put together, it would fit on a football field and rise less than 10 yards high.
There are three solutions that will make nuclear waste management even easier in the years to come: repositories, reprocessing, and recycling.
- Repositories can be dug in remote areas with stable geology to safely isolate nuclear materials for millions of years.
- Used nuclear fuel can also be reprocessed. Reprocessing means separating the plutonium and other useful materials from the used fuel and refabricating it into new fuel assemblies, significantly reducing waste volumes.
- Innovations in reactor design and advanced nuclear technology are starting to put recycling nuclear waste closer within reach. Beyond plutonium, all heavy radioactive isotopes in used nuclear fuel could be consumed in specialized waste-burning fast reactors.
Nuclear has sufficient fuel availability
Nuclear is a clean energy source but not a renewable one, since there is a finite amount of nuclear fuel material in the Earth’s crust.
However, estimates indicate that there is more than enough uranium to power the world on nuclear power for hundreds, if not thousands, or even billions of years, depending on the extraction method.
Considering its scalability, nuclear power presents one of the most practical ways to decarbonize the energy sector and reach net-zero emissions by 2050.
Are Nuclear Power Plants Good for the Energy Landscape?
Besides producing zero emissions during operation, low lifecycle emissions, and little-to-no environmental pollution, nuclear plants meet criteria that show they could be good for the energy landscape.
Nuclear energy is reliable
In 2021, U.S. nuclear plants operated 92.7% of the time. Global reliability factors for nuclear power plants are consistently above 90%. While other energy sources can struggle with intermittency, nuclear plants consistently and reliably provide energy that can meet the demand and needs of the grid.
Nuclear energy is scalable
Nuclear has a very small land footprint and a very high power output, making it extremely scalable. From a simple zoning perspective, it would be a lot easier to build 100 new nuclear plants than to cover an area larger than Delaware with wind farms — but both would provide the same amount of power.
Nuclear energy is flexible
Historically, nuclear reactors have been considered baseload electricity sources that plan to operate at full power.
This meant that nuclear power didn’t respond well to fluctuations in demand, like when energy consumption spikes on a hot afternoon when countless homes simultaneously turn on the air conditioning.
However, when used at scale and with modern innovations, nuclear plants are gaining more flexibility. France has used small variations in nuclear reactor power levels to respond to changes in electricity demand load, efficiently producing power for the grid while saving money.
Nuclear energy could be profitable
Nuclear plants have always been large investments, and they currently come with a very high price tag. Innovations, advanced nuclear technology, and economies of scale may help decrease costs, making nuclear plants easier to build and nuclear electricity cheaper.
For example, small modular reactors (SMRs) hope to simplify reactor designs. Some SMR developers intend to build modules, or even whole reactors, on an assembly line and ship them to plant sites, dramatically reducing complicated construction costs and timelines.
This article is one of many developed by EPRI’s Advanced Nuclear Technology program. Stay up-to-date on the newest nuclear technologies by becoming a member today.