Nuclear fusion seems a great solution for the demand of Energy. It is safe, has infinite fuel, produce a negligible amount of waste etc.
There are enormous technical challenges still to overcome, but let’s assume one moment, for the sake of the argument, that we find a way to solve them and the power plant is now “technically ready”.
Reading around seems that the cost of such plant will be huge: a lot of material required, complexity in the construction etc. Such construction costs include a very relevant energy price. For instance digging all the material and “transform” them requires a lot of energy. I have the feeling that the energy produced all over the life cycle has the same order of magnitude: i.e. at the end the “net balance” is not so convenient. Considered the huge capital cost the ration “Net energy produce / cost” would be quite poor as well.
This is just a feeling; does someone have arguments/publication pro or against this idea?
Nuclear fusion is the most basic form of energy in the universe. It is what powers the sun (pictured) and all of the stars. It is produced by a nuclear reaction in which two atoms of the same lightweight element, usually an isotope of hydrogen, combine into a single molecule of helium, the next heavier element on the periodic table.
Humans have successfully produced an uncontrolled fusion reaction to make the hydrogen bomb, in which all the tremendous energy of the reaction is released at once in a highly destructive manner. If the same amount of energy could be released gradually, in a controlled fusion reaction, which is what occurs in the sun, this could become the ultimate form of energy on Earth.
But creating a controlled fusion reaction has proven very difficult so far. Because the two hydrogen atoms have the same charge, they will electrically repel each other. The tremendous heat of the sun, which is somewhere in the neighborhood of 12 million degrees C, accelerates them to the point where their momentum overcomes the electric repulsion. Producing these kinds of temperatures in what is essentially a synthetic sun is a great engineering challenge. The elements are heated until they reach a plasma state. No material could possibly withstand such heat without melting, which is why the reacting elements must be suspended without touching the walls in the vessel. This can be done with either gravity, inertia, or magnetism, all of which are very challenging to create and control. The resulting continuous reaction, known as a thermonuclear reaction, could then be used to create steam in a boiler, which could then generate electricity using a conventional turbine.
The experimental reactors that are in use today all use deuterium and tritium as the main elements. Deuterium can be extracted from sea water. Tritium can be made from deuterium in contact with lithium.
Fusion research began in the 1950’s, in England. In 1968 the Russians created the first reaction in their Tokomak reactor, which utilized magnetic confinement. In 1991, the Joint European Torus (JET) reactor produced 1.7 MW. Two years later, the US-based Tokomak fusion test reactors (TFTR) produced 10 MW. Today there are some 25 experimental reactors in existence. The most ambitious is the International Thermonuclear Experimental Reactor (ITER) currently under construction in France, which hopes to achieve 500 MW of output for approximately 1000 seconds. The earliest projected date for a commercial facility is not expected until around 2050.
No one knows when a successful continuous controlled fusion reaction can be achieved or even if it is ultimately possible. Billions of dollars have been and continue to be invested in research since the potential benefit is considered so great.
Pros of nuclear fusion
• Clean energy. No greenhouse gases.
• Virtually limitless fuel available. (The deuterium can be distilled from seawater and the tritium can be “bred” in the reactor.)
• No chain reaction. Easier to control or stop than fission.
• Little or no nuclear waste. Core remains radioactive for only 100 years. Possibly radioactive structural elements.
• Very low fuel cost
Cons of nuclear fusion
• Unproven at anything resembling commercial scale.
• No full scale production expected till at least 2050.
• Commercial power plants would be extremely expensive to build.
• Requires extremely high temperatures difficult to contain.
• Could produce a net negative amount of energy. If cold fusion could be achieved, it would be much easier to implement.
• The billions in research funding could be spent on renewables or any other energy sources instead.
• Would remove any incentive for restraint in the use of energy.
In many ways, fusion power seems like the perfect energy source. It’s clean, it’s inexpensive, and it uses seawater as its fuel source. If commercial scale fusion plants were to become a reality, we would have an unlimited, nearly free, clean source of energy. And if limited energy supply and climate change were our only problems, or, should I say the only geophysical constraints imposing themselves on our way of life, then that would be the happy ending to the story.
There is one further and perhaps more immediate concern about the fusion scenario. It is not expected to be commercially available until somewhere around 2050. If you believe the projections on climate change, we pretty much need to have our energy house in order by then, with a dramatically lower carbon footprint that needs to begin dropping yesterday. The DOE has forecast that the US can meet 80% of its electricity demand from renewables by that time using existing technology while Denmark will be fulfilling 100% of its total energy needs with renewables by then.
Given that the fusion approach, will not, failing any miraculous breakthroughs, be ready by the time we need it, which is very soon if not now, it could be argued that it makes more sense to spend those billions of research dollars on something that will be.
The description of fusion as “sustainable”, or, alternatively, of it satisfying the requirements of “sustainability”, has become common, particularly in the fusion community itself. According to a recent newsletter of the European Fusion Development Agreement (EFDA): “The path that leads toward using fusion as a sustainable source of energy for the future goes via the exploitation of the next generation of fusion devices, and in particular ITER, which is designed to demonstrate the scientific and technical feasibility of fusion” .
If we look at current world energy supply, the application of the stricter definition of sustainability gives a very negative result. At present, global energy supply relies to the extent of 81 % on fossil fuels, which are – quite apart from being the main cause of anthropogenic
CO2 emissions – valuable natural resources of the planet and threatened by exhaustion in the next centuries. The so-called renewable energy forms – mainly biomass and combustible waste as well as hydroelectricity – only account for 13%. Although the terms “renewable” and “regenerative” are not good physical descriptions, the latter are of course almost by definition sustainable, because their origin is in most cases the sun, which is “limitless” as a source of energy, at least for the next 4 billion years!
Research on renewable energies is now attracting considerable funding. The development of nuclear fusion by the middle of this century is also one of main components of energy R&D policy in many countries. Fusion is seen by some as an alternative to nuclear fission, which at present accounts for 5.9 % of world energy supply (13.8 % of world electricity production), in particular for base-load electricity supply. The application of strict sustainability criteria to fusion focuses the discussion onto two issues: the serious problem of nuclear waste and the availability of the fusion fuels – deuterium and lithium – as well as of other materials in a future power plant, in particular the necessary neutron multiplier(s). If we can assume that recent favourable prognoses concerning the waste in future fusion power plants hold true, then the discussion centres on the extent of natural resources, in particular of lithium. Although this issue has been treated by several experts, there are three reasons for looking at the problem again:
• Firstly, the recent predictions of future demand for lithium-ion batteries are alarming: it is conceivable that the automobile industry may acquire, and according to some estimates even use up, at least the terrestrial lithium reserves in the next few decades.
• Secondly, although this could be regarded as a mitigating factor, the latest conceptual designs for the tritium breeding blankets in the DEMO fusion reactor have much smaller initial lithium loadings than those expected from the European Power Plant Conceptual Study (PPCS).
• Thirdly, the debate as to the practical limits of sustainability and of sustainable development has recently moved from the more academic fields of environmental ethics and ecological economics into the more journalistic domain, so that the political implications of the claims of the fusion community in this respect should be carefully examined.
It is important to highlight that a group of scientists in the USA generated more energy from fusion reactions than they put into the nuclear fuel, in a small but crucial step along the road to harnessing fusion power. The ultimate goal – to produce more energy than the whole experiment consumes – remains a long way off, but the feat has nonetheless raised hopes that after decades of setbacks, firm progress is finally being made.
Fusion energy has the potential to become a radical alternative power source, with zero carbon emissions during operation and minimal waste, but the technical difficulties in demonstrating fusion in the lab have so far proved overwhelming. While existing nuclear reactors generate energy by splitting atoms into lighter particles, fusion reactors combine light atomic nuclei into heavier particles.
Nuclear fusion is the most basic form of energy in the universe. It is what powers the sun (pictured) and all of the stars. It is produced by a nuclear reaction in which two atoms of the same lightweight element, usually an isotope of hydrogen, combine into a single molecule of helium, the next heavier element on the periodic table.
Humans have successfully produced an uncontrolled fusion reaction to make the hydrogen bomb, in which all the tremendous energy of the reaction is released at once in a highly destructive manner. If the same amount of energy could be released gradually, in a controlled fusion reaction, which is what occurs in the sun, this could become the ultimate form of energy on Earth.
But creating a controlled fusion reaction has proven very difficult so far. Because the two hydrogen atoms have the same charge, they will electrically repel each other. The tremendous heat of the sun, which is somewhere in the neighborhood of 12 million degrees C, accelerates them to the point where their momentum overcomes the electric repulsion. Producing these kinds of temperatures in what is essentially a synthetic sun is a great engineering challenge. The elements are heated until they reach a plasma state. No material could possibly withstand such heat without melting, which is why the reacting elements must be suspended without touching the walls in the vessel. This can be done with either gravity, inertia, or magnetism, all of which are very challenging to create and control. The resulting continuous reaction, known as a thermonuclear reaction, could then be used to create steam in a boiler, which could then generate electricity using a conventional turbine.
The experimental reactors that are in use today all use deuterium and tritium as the main elements. Deuterium can be extracted from sea water. Tritium can be made from deuterium in contact with lithium.
Fusion research began in the 1950’s, in England. In 1968 the Russians created the first reaction in their Tokomak reactor, which utilized magnetic confinement. In 1991, the Joint European Torus (JET) reactor produced 1.7 MW. Two years later, the US-based Tokomak fusion test reactors (TFTR) produced 10 MW. Today there are some 25 experimental reactors in existence. The most ambitious is the International Thermonuclear Experimental Reactor (ITER) currently under construction in France, which hopes to achieve 500 MW of output for approximately 1000 seconds. The earliest projected date for a commercial facility is not expected until around 2050.
No one knows when a successful continuous controlled fusion reaction can be achieved or even if it is ultimately possible. Billions of dollars have been and continue to be invested in research since the potential benefit is considered so great.
Pros of nuclear fusion
• Clean energy. No greenhouse gases.
• Virtually limitless fuel available. (The deuterium can be distilled from seawater and the tritium can be “bred” in the reactor.)
• No chain reaction. Easier to control or stop than fission.
• Little or no nuclear waste. Core remains radioactive for only 100 years. Possibly radioactive structural elements.
• Very low fuel cost
Cons of nuclear fusion
• Unproven at anything resembling commercial scale.
• No full scale production expected till at least 2050.
• Commercial power plants would be extremely expensive to build.
• Requires extremely high temperatures difficult to contain.
• Could produce a net negative amount of energy. If cold fusion could be achieved, it would be much easier to implement.
• The billions in research funding could be spent on renewables or any other energy sources instead.
• Would remove any incentive for restraint in the use of energy.
In many ways, fusion power seems like the perfect energy source. It’s clean, it’s inexpensive, and it uses seawater as its fuel source. If commercial scale fusion plants were to become a reality, we would have an unlimited, nearly free, clean source of energy. And if limited energy supply and climate change were our only problems, or, should I say the only geophysical constraints imposing themselves on our way of life, then that would be the happy ending to the story.
There is one further and perhaps more immediate concern about the fusion scenario. It is not expected to be commercially available until somewhere around 2050. If you believe the projections on climate change, we pretty much need to have our energy house in order by then, with a dramatically lower carbon footprint that needs to begin dropping yesterday. The DOE has forecast that the US can meet 80% of its electricity demand from renewables by that time using existing technology while Denmark will be fulfilling 100% of its total energy needs with renewables by then.
Given that the fusion approach, will not, failing any miraculous breakthroughs, be ready by the time we need it, which is very soon if not now, it could be argued that it makes more sense to spend those billions of research dollars on something that will be.
The description of fusion as “sustainable”, or, alternatively, of it satisfying the requirements of “sustainability”, has become common, particularly in the fusion community itself. According to a recent newsletter of the European Fusion Development Agreement (EFDA): “The path that leads toward using fusion as a sustainable source of energy for the future goes via the exploitation of the next generation of fusion devices, and in particular ITER, which is designed to demonstrate the scientific and technical feasibility of fusion” .
If we look at current world energy supply, the application of the stricter definition of sustainability gives a very negative result. At present, global energy supply relies to the extent of 81 % on fossil fuels, which are – quite apart from being the main cause of anthropogenic
CO2 emissions – valuable natural resources of the planet and threatened by exhaustion in the next centuries. The so-called renewable energy forms – mainly biomass and combustible waste as well as hydroelectricity – only account for 13%. Although the terms “renewable” and “regenerative” are not good physical descriptions, the latter are of course almost by definition sustainable, because their origin is in most cases the sun, which is “limitless” as a source of energy, at least for the next 4 billion years!
Research on renewable energies is now attracting considerable funding. The development of nuclear fusion by the middle of this century is also one of main components of energy R&D policy in many countries. Fusion is seen by some as an alternative to nuclear fission, which at present accounts for 5.9 % of world energy supply (13.8 % of world electricity production), in particular for base-load electricity supply. The application of strict sustainability criteria to fusion focuses the discussion onto two issues: the serious problem of nuclear waste and the availability of the fusion fuels – deuterium and lithium – as well as of other materials in a future power plant, in particular the necessary neutron multiplier(s). If we can assume that recent favourable prognoses concerning the waste in future fusion power plants hold true, then the discussion centres on the extent of natural resources, in particular of lithium. Although this issue has been treated by several experts, there are three reasons for looking at the problem again:
• Firstly, the recent predictions of future demand for lithium-ion batteries are alarming: it is conceivable that the automobile industry may acquire, and according to some estimates even use up, at least the terrestrial lithium reserves in the next few decades.
• Secondly, although this could be regarded as a mitigating factor, the latest conceptual designs for the tritium breeding blankets in the DEMO fusion reactor have much smaller initial lithium loadings than those expected from the European Power Plant Conceptual Study (PPCS).
• Thirdly, the debate as to the practical limits of sustainability and of sustainable development has recently moved from the more academic fields of environmental ethics and ecological economics into the more journalistic domain, so that the political implications of the claims of the fusion community in this respect should be carefully examined.
It is important to highlight that a group of scientists in the USA generated more energy from fusion reactions than they put into the nuclear fuel, in a small but crucial step along the road to harnessing fusion power. The ultimate goal – to produce more energy than the whole experiment consumes – remains a long way off, but the feat has nonetheless raised hopes that after decades of setbacks, firm progress is finally being made.
Fusion energy has the potential to become a radical alternative power source, with zero carbon emissions during operation and minimal waste, but the technical difficulties in demonstrating fusion in the lab have so far proved overwhelming. While existing nuclear reactors generate energy by splitting atoms into lighter particles, fusion reactors combine light atomic nuclei into heavier particles.
In a few words ... we should understand and use nuclear fusion, and we have to do it at a viable cost in a period which I estimate between 50 and 200 years. Or we can not supply power to all consumers.
I think every energy source is being deployed following its specific fit to an overall energy mix. Wood was replaced by... and so on. At this point, considering all developments in fusion vs. current conditions of energy markets and energy grids, it is very difficult to see how fusion would fit in. Being fundamental on a planetary or universe scales, may not mean it is a good fit as an energy source for humans. Within 200 years time scale, there still will be gas and oil and plenty of nuclear power (fission). Grids may become more distributed and decentralized to accommodate renewables. Those developments are not towards a realm of fusion power.
This is a weird question. It's a little like asking if we all had unicorns, would we be better off? We don't have usable nuclear fusion. We wish we did. We're working on it, and there is no likelihood of it providing a significant portion of our energy mix in the next few decades. Due to the complexity of the reactor and amount of infrastructure and training required to support it, it is very unlikely that this will be a solution for the poorest 4 quintiles of the world population.
The nearest fusion reactor that seems to be viable now and for the foreseeable future is 93 million miles away. We use it's energy continuously. It delivers its energy in a fairly predictable pattern to everyone on the planet. It feeds all of the planet, not just humanity. It benefits everyone regardless of wealth. So, yeah, fusion is sustainable. We call it solar.
- Badges
- Science topic