All energy sources have impacts that are important to consider. However, when faced with such an important crisis like climate change, it becomes a game of priorities rather than waiting around for the perfect solution.
Right now, the priority is phasing out fossil fuels from the energy grid. Decarbonization is the name of the game, and fossil fuels are the worst carbon emitters. Unfortunately, we’ll need other technologies to compensate for the massive quantities of energy they currently produce. And if our goal truly is to decarbonize the atmosphere as fast as possible, then nuclear fission may be an acceptable alternative.
Nuclear fission [or just ‘nuclear’ for short] supplied 4.9% of the global energy mix in 2018 and 10.3% of the global electricity mix in 2019. Nuclear power plants work in a somewhat similar way to fossil fuel power plants, where heated water turns to steam to rotate a turbine and generate electricity. It’s before that – to heat the water – that nuclear power plants set themselves apart from fossil fuels.
To heat the water, nuclear energy is harvested from a very specific fuel: uranium-235, which is basically normal uranium that we extract/enrich to make it extra radioactive [other technologies are available but are much rarer]. More radioactivity means more nuclear fission, which means more energy output. But what is fission?
Every atom contains energy, and some of that energy helps keep protons and neutrons held tightly together [in the nucleus] – that’s called nuclear energy. If an atom were to split in 2, then the atom would release some of that nuclear energy, since there’s less components to ‘stick’ together.
Nuclear reactors take advantage of that. Uranium rods are placed inside of water, and are then ‘excited’ [kind of like giving a car a jump-start] to start the whole process off. The beauty of a uranium-235 atom is that it can release 3 neutrons once excited, and each of those neutrons have more than enough energy to excite other uranium-235 atoms – which would then release 3 more neutrons once hit.
This energy pyramid scheme is called a fission chain reaction. With each neutron moving through the water and atoms releasing nuclear energy as they split – the water starts heating up. Obviously, this is a simplified explanation, but that’s the general concept.
Nuclear power plants depend on a steady fuel supply and consume that fuel during energy production, just like fossil fuel power plants. However, that’s where the comparisons stop between the 2 energy production methods.
Unlike fossil fuels, nuclear fission is a low-carbon energy source, since the fuel isn’t combusted. Additionally, nuclear fission is a much more efficient process. Thanks to uranium’s extremely high energy content, a very small amount of uranium can produce lots of electricity.
Both these factors explain why nuclear fission can be a better option than fossil fuels as we complete our energy transition.
The place of nuclear energy is still uncertain in today’s world. It’s fascinating that governments still can’t decide whether to invest in nuclear energy, even though we know we need to phase out fossil fuels – and nuclear can help generate low-carbon baseload electricity. That’s how many disadvantages it has. No matter what the near future holds for nuclear energy, its many drawbacks seem to make it an undesirable energy source in a post-fossil-fuel world.
First, nuclear fuels like uranium are not renewable sources of energy. Since mining, refining, and enriching uranium are polluting processes, we don’t really want to keep doing that in a distant sustainable future. It’s one thing to have those types of impacts during the technology’s production stage [like renewables do] – but having continuous impacts to ensure steady uranium supply is another.
Second, just like renewables, nuclear power plants can have considerable life-cycle impacts. They’re massive facilities that require loads of high-impact natural resources to make sure safety [concrete, steel], efficiency [rare metals], and waste disposal [water, concrete, steel] are up to code.
Lastly, nuclear waste is a serious concern. ‘Fission products’ like the cesium-137 and strontium-90 radioactive isotopes [atoms that aren’t well balanced] are 2 examples of high-level radioactive waste that could have devastating effects on the environment. They’re much more radioactive than plutonium [another byproduct of the reaction], but plutonium is around for much longer. In fact, plutonium-239 has a half-life of 24,000 years, compared to 30 years for the 2 isotopes [half-life means half the isotopes would decay in that time – but it would take much longer than 48,000 years to get rid of all of them]. Goodie for us that this nuclear waste is being handled with the outmost care and stored in deep pools of freshwater or buried deep into the ground – in both cases surrounded by steel and concrete.
While that last point may be reassuring for now, it’s not a very good solution in the long run. Quite simply because there’s great uncertainty regarding the state of the planet in 1,000 years, let alone 100,000+ years [e.g. a millennium ago Europeans were launching rocks into each other’s fortresses]. How can we ensure this waste will stay safe? That’s a pretty important question considering that plutonium and other radioactive isotopes will contaminate ecosystems and entire food chains if improper waste handling/storage occurs.
The fundamental issue with nuclear power plants is that they can’t afford the slightest mishap. While they wouldn’t explode in a nuclear-bomb fashion, any radioactive matter that escapes its enclosure would spread like the wind. Unfortunately, we can never be sure that accidents won’t happen again – as shown by the Earthquake-and-Tsunami-hit nuclear power plant in Fukushima. And with climate change, placing these reactors in safer areas is becoming more of a guessing game, due to highly variable meteorological events.
Having seen the benefits and drawbacks, it’s clear that nuclear energy is complicated and will undoubtedly continue to spark debates between industry experts and governments. Whether the risks, current impacts, and costs of nuclear energy are ‘worth it’ to phase out fossil fuels remains to be seen.
Although numerous new technologies and fuels are being researched for nuclear power, it’s unclear whether these advances will be developed in time to curb GHG emissions. That will depend on the speed at which governments choose to phase out fossil fuels.
Governments will therefore have to plan ahead to evaluate whether investing in nuclear is a good idea or not. Due to radioactive waste and nuclear’s other disadvantages, developing new nuclear technologies for a post-fossil-fuel world might not make sense.
Currently, it seems as though most developed countries have lost faith in nuclear energy – even though low-carbon policies continue to gain steam. While developing countries continue to install new reactors, developed countries’ nuclear generation capacity is projected to fall by 25% from 2018-2025. Although that’s mostly caused by nuclear power plants in those countries reaching end of life – it shows that governments aren’t willing to build more plants to compensate.
There’s a lot of buzz around nuclear fusion these days. In fact, there has been for over half a century. A lot of that’s due to the fact that we keep making breakthroughs, yet continue to be decades away from having any energy-producing prototypes.
Nuclear fusion consists of heating plasma at extremely high temperatures to spark and sustain fusion reactions – which generate energy. It’s how the Sun produces energy/light, and replicating that at a much smaller scale on Earth would theoretically help us produce unlimited emission-free energy. However, it would still produce radioactive waste that would need to be properly disposed of – though the waste decays much faster than that of a fission reaction.
Nuclear fusion has drawn a lot of criticism for its empty promises over the last few decades. Although this energy source would be extremely helpful for the energy transition, we just can’t seem to get it done it time. There are loads of technical problems associated with heating plasma to a temperature of 150 million degrees Celsius [for the ITER project], but they can all be summed into one central issue: the energy output from the reaction remains much smaller than the energy input, even after decades of testing and designing new reactors.
The fact that we keep making breakthroughs but are still so far from concrete results isn’t a good sign. A star’s fusion reactions can take place because the atoms that fuse together are tightly bound by the star’s immense gravitational force. On Earth, it’s much harder to replicate that – so we have to develop and master new technologies to allow fusion to take place in controlled environments. Unfortunately, that’s easier said than done – as the current plan seems to be testing out new technologies as we go. This is an approach that many innovative companies have adopted over the years, each with their own twist on fusion [with varying levels of success].
The world’s largest fusion project ITER also requires fuel input in the form of deuterium and tritium [2 hydrogen isotopes]. While deuterium can be extracted from a virtually endless supply [an argument we’ve heard before when talking about fossil fuels] of seawater, we aren’t able to produce tritium at a large enough scale to start thinking about commercial applications of fusion just yet [current tritium reserves are near 20 kg].
Nonetheless, billions are invested in nuclear fusion projects despite no proof that sustained fusion reactions are even possible in the next few decades. For example, ITER had an estimated cost of around €20 billion EUR in 2016 – despite not having performed a single test run [the first test run was originally planned in 2016].
Conclusion – Nuclear Fusion
As was the case for nuclear fission, we need to define our priorities. Nuclear fusion won’t be available in time to accelerate the phasing out of fossil fuels, so governments will have to decide whether funding fusion projects currently makes sense.
If we do eventually achieve sustained fusion, it will only help us decrease our dependence on renewables in many decades [assuming we meet climate targets by phasing out fossil fuels]. Although that could reduce mining and other impacts of renewables, the focus has to remain on phasing out fossil fuels. Especially since there’s no guarantee we can get fusion to work. As for its potential impacts on the environment, it’s certainly quite bold to declare that commercial fusion reactors will be eco-friendly sources of energy. For the simple reason that we don’t even know what successful fusion looks like.
Finally, it’s important to note that ‘miraculous’, unlimited, and emission/waste-free sources of energy would only solve one part of the puzzle. As we’ll see in later sections, it’s not only about how we produce energy – it’s also about what we use it for.