In order to stay on track to meet the goal of net zero emissions by 2050, low carbon sources need to meet the interim goal of generating 75% of global energy by 2030, according the IEA. That goal can only be reached if most of the world's energy mix is renewable and nuclear energy combined by 2030. Although renewable energy is projected to make up the majority of that low carbon mix, nuclear should still be a significant share.

Today, nuclear and renewable energy are widely used climate solutions needed in order to reach the 2030 goal. Other low carbon energy sources will hopefully come online at commercial scale in the next several years to help fill in the gap of ambitious net zero goals. Nuclear and renewable energy both represent currently available, large-scale energy technologies. In the IEA World Energy Outlook, renewables are projected to be about 60%, and nuclear just over 10%, of global energy; in order to reach the 2030 low carbon global energy mix goal.

Zero carbon emission energy

 Doel nuclear power station in Antwerp
Doel nuclear power station in Antwerp (represents over 20% of total energy for Belgium)

Wind and solar are renewable energy sources which are zero emission energy sources; however they are also intermittent and variable. Nuclear, is also a *"zero" emissions (zero carbon dioxide emissions) energy source;. However nuclear continuously generates energy, representing reliable energy with the highest capacity factor of any energy source.

Widespread global use of nuclear energy will help the world reach net zero emissions faster. Burning nuclear fuel emits no carbon. *GHG emissions from the lifecycle of nuclear power plants are on par with wind and solar. These are not emissions associated with the generation of energy; rather emissions during the lifecycle of the power plant or renewable energy farm (so, during the transportation of needed capital for the power plant or energy farm, for example. Mining and transporting uranium for fuel is another example).

The water vapor seen coming from nuclear cooling towers are the only emissions; the result of steam created by using water for cooling. Renewable energy and nuclear energy both produce little to no GHGs during the energy production process, no CO2, and both forms of energy do not contribute significantly to anthropogenic climate change.

Is nuclear energy clean energy?

nuclear energyNuclear power is somewhat clean (see the notes about toxic waste generated by nuclear power plants below), and is becoming much safer (see the notes about Gen IV nuclear below). Nuclear energy, though NOT a renewable energy source, represents a much more concentrated source of energy than fossil fuels or renewables. A pound of nuclear fuel holds 1 million times more potential for energy production than a pound of fossil fuels, and fossil fuels have a higher energy density than renewables, so nuclear has the highest energy density of any energy source.

Nuclear energy has a significantly higher energy production capacity than other energy sources, especially considering that only a relatively small quantity of the fuel (uranium currently, thorium for future consideration in Gen III, IV plants) is required for nuclear power plants. A small amount of a fossil fuel, say 1 kg of coal, can only keep a light bulb lit for a few days; while the same quantity of fuel from a nuclear energy source will keep the same bulb lit for well over 100 years. Nuclear does this without any CO2, or most other GHG emissions, from the  power plant.

Does a nuclear power plant produce CO2 emissions?

To be clear, once a nuclear power plant is at the operational stage, carbon dioxide emissions from a nuclear reactor are zero. Greenhouse gas emissions (GHGs) from mining and refining uranium into nuclear fuel, transporting toxic waste from nuclear sites to safely store the waste, and maintenance for nuclear reactors are energy-intensive activities that do produce GHGs.

Therefore, nuclear energy production must be considered as a part of the world energy mix needed to fight anthropogenic climate change. [*Note: neither nuclear nor renewables are actually completely "zero" GHG emissions, but both are relatively just as close to zero emissions as possible; and close enough to zero to be worthy of being called "clean energy", "zero emission" energy sources].

Summation of the global need for nuclear energy

Wind and solar are intermittent renewable energy sources. Nuclear energy, while not a renewable energy source, is an energy-dense, constantly dischargeable, fuel source. Nuclear is also a zero carbon emissions source.

In order to provide global zero emission energy on a scale to mitigate climate change, both nuclear and renewable energy's contribution to energy production on the planet must increase. The immediate goal, fully attainable, should be getting zero and low carbon energy to a combined energy production level which is significantly more than what coal alone currently provides (almost 40% of total global energy production is from coal).

Advanced nuclear (small modular reactor, Gen IV nuclear, some Gen III - see below) are designed to be much more safe and efficient than current reactors.

Both nuclear and renewable energy are needed in the global energy mix to help fight climate change

In order to cut down on the share of fossil fuels in the world energy mix, nuclear is necessary. A total of WELL OVER 40% of the world's energy mix for renewable and nuclear energies combined is needed to reach significant greenhouse gas emission reduction targets. Over 40% is not a final goal, but represents a realistic initial goal on the path towards the target of over 70% clean, zero emission global energy generation.

To achieve a significant GHG emissions reduction target for the planet, the world needs nuclear energy. Nuclear energy is going to have to augment truly environmentally-friendly, renewable energy in the effort to dramatically reduce fossil fuel use.

How much of the world's energy is nuclear?
global energy mix
global energy mix 2021

Nuclear reactors provided 10% of the world's total energy sources, on average annually, during the last decade. 13 countries get at least 1/4 of their energy from nuclear, including France (which gets around 3/4 from nuclear), Belgium, Sweden, Switzerland, and Finland.

Nuclear energy is also put to great use in the US, France, China, Russia, and South Korea, among other countries. Now is probably as good of time as any in this article to mention a couple major drawbacks (to put it mildly) of nuclear energy. Namely the danger- catastrophic disasters due to large-scale accidents like the one at Fukushima, Japan, enrichment of uranium in order to create nuclear weapons, and the difficult, expensive process of securely managing the disposal of nuclear waste.

The former major problems mentioned (and less waste generated by the nuclear process - Gen IV theoretically can just run on spent uranium) are resolved in the 4th generation nuclear reactor designs, discussed below.

Nuclear Power Today | Nuclear Energy - World Nuclear AssociationCurrent reactors, mostly Gen I & II nuclear plants, along with several operational Gen III plants, rely on uranium and water (to cool the plants). Therefore, these nuclear plants still deplete water supplies, create nuclear waste, use a fuel source that can be enriched to convert the material into a bomb, and represent a source of potential danger.

The largest nuclear disaster in history was the Chernobyl disaster (although the risk of nuclear disaster is dramatically minimized in a Gen III plant, and eliminated in Gen IV nuclear. Some Gen IV designs dramatically cut the need for water to cool plants, as well).

Here's a brief snippet from the World Nuclear Association summarizing nuclear energy's current role in the global energy mix:

  • The first commercial nuclear power stations started operation in the 1950s.
  • Nuclear energy now provides about 10% of the world's electricity from about 440 power reactors.
  • Nuclear is the world's second largest source of low-carbon power (29% of the total in 2018). 
  • Over 50 countries utilise nuclear energy in about 220 research reactors. In addition to research, these reactors are used for the production of medical and industrial isotopes, as well as for training.  FROM  -

Advanced nuclear reactors

Safer, cheaper, still energy abundant and emissions-free designs that use relatively benign energy sources (thorium or depleted uranium), and much less water for cooling the reactor than previous designs and current operational nuclear plants, are being envisioned in 4th generation nuclear, and are currently available in a few 3rd generation nuclear power plant designs.

Using a small fraction of the water as previous designs, Gen IV nuclear plant designs, are safe, cost-effective, environmentally-friendly, and still offer tremendous potential for energy production. Molten salt reactors using depleted uranium, nuclear waste from other plants, or thorium as complete replacement of uranium, are being planned in Gen IV nuclear plant designs. 4th generation designs (and many 3rd generation plants, both planned and operational) are autonomous, smart plants, with heightened safety measures.

Thorium  is being looked at as a fuel source for new nuclear reactors, as it is abundant, much less radioactive than uranium, and creates by-products from burning the fuel source that can be used again in the reactor. There is a higher level of thorium than uranium on the planet. Thorium, as well as depleted uranium, are being designed with relatively lower up-front capital costs. Little manpower is needed to run and maintain future, advanced 4th generation nuclear plants, due to the autonomous computer technology set to be deployed in the plants.

Summation of the benefits of advanced nuclear reactors

Nuclear reactors designed to run on thorium, and depleted uranium, have a very low chance of being developed into a nuclear weapons, produce less radioactive waste, are abundant fuel sources; and are safer, more cost-efficient in addition to being energy-efficient, and cleaner vis-a-vis energy generation compared to current widely deployed nuclear reactors..

Thorium, in particular, is being looked at by developing nations like China and India because of the relatively low cost, increased safety, abundance of the material, and tremendous energy potential of this energy source. The U.S. has huge amounts of thorium, in places like Kentucky and Idaho (as well as depleted uranium); and there are large quantities in countries like India, Australia and Brazil.

The U.S., Europe, and even some of the aforementioned developing countries, also have large stockpiles of depleted uranium. More depleted uranium is being produced every day, which would work in many of the 4th generation designs. A few 3rd generation nuclear plants are already operating, and some more are projected to be developed and ready for operation by 2025. 4th Gen nuclear promises to produce abundant, low-cost energy safely, and with little environmental impact.

In order to meet increased demand for low-emission, safer, lower up-front capital investment, high-efficiency energy sources, there has also been an increased global interest in light water small modular nuclear reactors (SMRs). Benefits of nuclear SMRs include-

Small modular reactors offer a lower initial capital investment, greater scalability, and siting flexibility for locations unable to accommodate more traditional larger reactors.  They also have the potential for enhanced safety and security compared to earlier designs. Deployment of advanced SMRs can help drive economic growth. From- USDOE Office of Nuclear Energy

One other "good" thing about nuclear energy production is that there are fairly low marginal costs. There are little to no negative externalities with regard to the actual energy production (i.e. little to no GHG emissions); however current nuclear power plants do generate toxic waste. Ongoing costs are fuel and maintenance of nuclear plants; the uranium to fuel the plants, and water to cool the plants, and toxic waste disposal facilities.

Large toxic waste disposal locations are necessary to bury the radioactive waste so people aren't exposed to potentially cancer-causing radiation. Nuclear power plants do also carry high up-front capital costs.

The US Energy Information Administration estimated that for new nuclear plants in 2019 capital costs will make up 75% of the levelized cost of energy.

Even when looking at the downsides of current technologies for nuclear energy production, 4th generation nuclear promises to be safe, cost efficient (cost of new nuclear fuel is low), and environmentally-friendly, with a very high energy production capacity given a relatively small quantity of nuclear fuel need for energy production (whenever 4th-gen nuclear gets built).

New reactors can (theoretically) run on spent uranium and even thorium. 4th generation nuclear has entirely safe, cost efficient designs. Actually, the levelized cost of energy production from new, advanced nuclear reactors that are already available, deployed, and generating nuclear energy, is looking viable.

For a comprehensive guide on public policy that increases nuclear energy globally, in order to help fight anthropogenic climate change, please see: Public policy proposal to stabilize greenhouse gas emissions

Please also see:

Renewable energy overview


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