Perch raises $30M from Nuveen to expand access to community solar savings for all Read >

Is Nuclear Energy Renewable Or Sustainable? Pros & Cons

Nuclear energy is technically not renewable because uranium is a finite source. But that doesn’t mean nuclear isn’t a cleaner and more carbon-efficient energy source.
Smoke coming out of the cooling towers at a nuclear pant.

Over the last few decades, nuclear power plants have been an integral piece of the United States’ energy generation strategy. The U.S. currently houses 93 total nuclear plants across the country, and in 2021, those nuclear plants accounted for roughly 20% of the country’s electricity generation—just 1% less than the total electricity generated by renewables such as solar, wind, and hydro.

Experts in climate, energy, and environment fields have varying thoughts on what role nuclear energy should play in our low-carbon future. Its proponents say it is an efficient use of space, produces little waste, and generates huge amounts of power. But opponents say there are serious problems with how we dispose of radioactive waste, the environmental damage caused by extraction, and the potential hazards of the power plants themseleves as they age. 

With no firm consensus on the question of nuclear energy's role in a low-carbon future, we will take a look at the pros and cons of nuclear energy to help you see what the fuss (and fission) is all about.

Is nuclear energy technically renewable?

The technical answer: no, because there is a finite amount of fuel. Nuclear power plants create energy through a process called nuclear fission, which involves the splitting of atoms to release energy. The process uses a chemical element called uranium to create fuel, and even though uranium can be found in rocks all over the world, the specific type of uranium that power plants require, uranium-235, is limited in supply. By some estimates there is only enough uranium-235 on the planet to power the earth for just 80 years at the current rate of consumption. Some other estimates say it may be closer to 200 plus years due to undiscovered uranium resources, but those years are capped since it is a finite resource. Therefore, nuclear energy is not a renewable energy source.

Is nuclear energy sustainable and clean?

While nuclear isn’t technically renewable, it is a cleaner source of energy than traditional fossil fuels. Energy is sustainable if it meets the needs of the present without compromising the ability of future generations to meet their own needs. The limited supply of fuel, potential for radioactive accidents, and waste that lasts for tens of thousands of years make nuclear energy unsustainable.

But nuclear energy is a very low-carbon way of providing electricity and has a lot of other benefits worth considering. Here are a few pros and cons.

Pros of nuclear energy

Nuclear power plants do not require much land, especially in comparison to solar and wind

The Nuclear Energy Institute claims that wind farms require 360 times as much land to generate the same amount of energy as a nuclear power plant. For solar, it would require 75 times the land area.

Nuclear power plants have extremely low carbon emissions

They generate energy by splitting atoms through a process called fission. The process generates heat which is used to create steam, and that powers a turbine to produce energy without emitting carbon as a byproduct. The lifetime emissions of nuclear energy generation are extremely low.

Nuclear fuel is extremely efficient

Although nuclear plants do produce nuclear waste that is toxic, the amount of waste produced is surprisingly small. In fact, the total nuclear waste generated over the last 70 years is equivalent to the amount of waste that coal plants produce in a single hour. That’s because nuclear fuel is very dense and contains a lot of energy in a very small quantity.

Thanks to these reasons, nuclear energy is generally clean. Even mining for uranium is remarkably emissions-light though every mining operation takes a significant physical toll on the environment. However, critics of nuclear hesitate in calling nuclear a completely clean source of energy because of the toxicity of the waste that it does produce. Storing nuclear waste requires extreme precaution and safety measures, and critics often cite the risk that nuclear waste poses to the environment and to our health if it is not handled correctly as one of the reasons that we should invest in renewable sources instead of nuclear.

Nuclear is very reliable

Nuclear is one of the most reliable energy sources in the world. One way to measure reliability is to look at the capacity factor of an energy source. Capacity factor measures the amount of time that an energy source is running at full capacity and producing energy.

Nuclear has the highest capacity factor of any other energy source, producing reliable, carbon-free power more than 92% of the time. That’s nearly twice as reliable as a coal (48%) or natural gas (57%) plant and almost 3 times more reliable than wind (35%) and solar (25%) plants.

This means, for every new nuclear plant we add, we can retire about two coal plants still keep the reliability of the grid relatively the same.

In contrast to nuclear, solar only generates energy when it’s sunny, and wind only generates energy when it's windy. Even though battery technology is rapidly improving, some energy experts doubt whether we can cheaply and effectively create a completely reliable energy grid just with variable renewable sources. Nuclear could help solve this issue because nuclear energy is not variable, meaning it does not depend on certain conditions to produce electricity.

Nuclear energy plants are cheap to run

Once Once a nuclear power plant is built, it is more cost-effective to run than fossil fuel power plants. These low costs include waste management. The operating cost of running nuclear plants is lower than the operating cost of running most fossil-fuel-dependent power plants.

Cons of nuclear energy

There are also downsides to nuclear energy, though. Most of us probably know the worst things that can happen when it comes to nuclear power. And while nuclear waste management and safety has become far more effective and enforced over the years, there are still some risks associated with generating energy from nuclear. Here are some of the top reasons experts are hesitant about nuclear power.

Nuclear energy plants are expensive to build

Although cheap to operate, nuclear energy plants are expensive to build, partly due to the safety measures that need to be put in place in order to build a safe nuclear plant. Over the last couple of decades, nuclear plants have actually gotten more expensive to build. Lots of those costs result from indirect costs of building plants, such as engineering, management, and supervision. Those costs have also risen due to increased safety regulations. However, some of these costs can be reduced through the construction of small modular nuclear reactors (SMRs) at old coal plants.

The waste is radioactive

We all know the story of what happens when something goes wrong at a nuclear plant. And while our understanding of nuclear and how to handle nuclear waste has evolved far beyond what it was 60 years ago, the fact that nuclear waste is toxic is still true. That waste can stay radioactive for a predicted 10,000 years. For many, the unknown side effects of storing nuclear waste in the environment and the risk of accidents are not worth the benefits of nuclear.

Uranium-235 is limited in supply

Although it is predicted that there is enough uranium-235 on the earth to power the world for 100s of years, it will run out eventually. It may be unwise to build an energy system that is destined to run out of supply.

Nuclear energy plants take a long time to build

While the World Nuclear Association estimates the average time to complete a reactor of between 5 and 8.5 years, the World Nuclear Industry Status Report showed it takes closer to a full decade to complete. Given the urgency of climate change, waiting on nuclear power plants to replace fossil fuel plants may make the goal of full decarbonization unreachable in the timeframe we need.

Should nuclear be a central part of our energy future?

When it comes to generating electricity, nuclear plants are far more efficient and clean than gas and coal alternatives. Therefore, many people argue that we should invest in nuclear in addition to solar, wind, hydro, and geothermal, citing benefits beyond just nuclear’s clean attributes.

Nuclear already plays a big role in generating the world’s electricity, and it is likely to continue to play that role in the years to come. The risks associated with generating nuclear energy are far less threatening today than they were decades ago thanks to increased safety protocol and technology. But as power plants age and must be decommissioned we need to consider nuclear power’s role in the long-term achievement of a clean power grid.

Moreover, nuclear energy is remarkably cheap to generate, extremely reliable and secure, and also far cleaner than fossil-fuel-dependent energy sources. Of course, there are still risks and unknowns when it comes to nuclear that give some energy experts pause. Not to mention, nuclear relies on a finite resource. So, the debate surrounding nuclear is sure to continue.

One thing is certain though. The world is in desperate need of cleaning up our energy system. And while we may not know if nuclear should play an expanded role in cleaning up that system, we do know that solar, hydro, wind, and other renewables will.

Get matched to a local solar farm and save on your electricity costs.