Here comes the power of the sun


 

The power of the sun, 4 trillion terawatts of pure, clean energy baby! That’s been the dream ever since the secret of the sun’s power was first gleaned by nuclear physicists almost a century ago. Fusion has been a long time coming, but we may finally be getting close:

BBC– These are embryonic stages to what is perhaps humankind’s most ambitious scientific and engineering project: to replicate the Sun here on Earth.When construction is complete, the pit will host a 73-metre-high machine (240 feet) that will attempt to create boundless energy by smashing hydrogen nuclei together, in much the same way as stars like our Sun do. Physicists have dreamed of being able to produce cheap, safe and plentiful energy through atomic fusion since the 1950s. Around the world, researchers continue to experiment with creating fusion energy using various methods. But as people within the field have said the dream has always been “30 years away” from realisation.

The need for a new energy source has never been more pressing. Global energy demand is expected to double by 2050, while the share coming from fossil fuels – currently 85% – needs to drop dramatically if we are to reduce carbon emissions and limit global warming.

Comments

  1. herp says

    Here’s hoping that the full scale ITER really produces the Q values needed to be self-sustained. *cheers*

    The biggest problem I see is the fuel source. Where are we going to get that much D2O and tritium? Sure D2O is fairly plentiful, but the tritium is far more scarce.

  2. Randomfactor says

    I recently read a joke that true artificial intelligence is just five years away…and when it arrives, it’ll be fusion-powered.

    (Fusion has ALWAYS been five years away.)

  3. Andrew G. says

    Where are we going to get that much D2O and tritium? Sure D2O is fairly plentiful, but the tritium is far more scarce.

    You make the tritium on the spot from lithium. By exposing lithium to the fast neutrons produced in the reactor, you get these reactions:

    6Li + n -> 4He + 3H

    7Li + n -> 4He + 3H + n

    The first reaction releases some additional energy. The second absorbs energy, but allows breeding more than one atom of 3H per neutron.

    If you need more 3H, the first of those reactions can be carried out using almost any convenient neutron source (it doesn’t need fast neutrons).

  4. billyeager says

    Now, don’t go hating on me, or laughing for that matter. But is the *only* way to produce ‘free’ electricity that which can physically spin a turbine?

    Most people would be surprised to know that Nuclear Power is only about the creation of steam as a propellant and, likewise, Fusion Energy is only really about the creation of steam for same purpose.

    I know we can create electricity by way of chemical reaction, is there not anything leading the field in this regards that would be more attainable towards the goal of ‘free’ energy?

    Or an other methods other for that matter?

  5. says

    Seems to me the closest thing to “free energy” would be indeed be fusion, i.e., the sun itself. The light is free, it doesn’t cost anything. Converting to electricity does take technology and research into more technology, often involving doped rare earths and always involving the same fossil fuels and grid system baked into our manufacturing and distribution industries.

  6. herp says

    You make the tritium on the spot from lithium. By exposing lithium to the fast neutrons produced in the reactor, you get these reactions:

    It’s always good to learn a bit of nuclear chemistry. Since Li is such a light atom, wouldn’t this reaction be relatively low even with hot neutrons? I’m certainly not an expert, but it was my impression that neutrons were largely non-reactive with low mass atoms. I know that you can use cold neutrons to “see” through solid objects like aluminum engine blocks, and that is more than 4 times the mass!

    As a side comment; they need to build a neutron source with this at the same time? So they need a nuclear reactor to get the fusion reactor up and running, interesting.

  7. Gregory in Seattle says

    I have a lot of doubts about fusion power. To over come electromagnetic repulsion twice — negatively charged electron shells, then positively charged nuclei — sufficiently to let the residual strong force come into play takes a tremendous amount of energy in and of itself. Stars manage it through the energy supplied by mass and gravity: there is simply no way we can replicate those conditions on Earth. Every human method that has managed fusion has used far more energy than was released, and sustaining that reaction has proven impossible.

    @billyeager #5 – At the levels needed for commercial application of electricity, batteries just are not sufficient: they last a relatively short time, require toxic chemicals that must either be reclaimed and recycled or disposed of, and produce only direct current, which has a very short transmission range. A turbine generator can produce electricity indefinitely as long as everything remains in good repair, requires few toxic chemicals, and produces alternating current, which has a very large transmission range. Also, most batteries have a sharp output gradient — a fresh battery produced much more electricity than one that has been in use for a while — while AC power generation remains constant. Consistent output is extremely important.

  8. says

    Why bother with fusion? We have a practically limitless supply of fissionable material- given that breeeder reactors can make that so.

    I am skeptical that fusion can deliver power with a significantly smaller rad waste footprint. There is a “whole lotta activation goin’ on!”

  9. Gregory in Seattle says

    @Stephen #6 – In the future history I’m working out for my science fiction writing, we have developed several methods for artificial photosynthesis, which remove CO2 from the atmosphere and produces either hydrocarbons for fuel or carbohydrates for food.

  10. KG says

    Fusion has been a long time coming, but we may finally be getting close

    No, we’re not; not as a viable source of energy, at any rate. Even optimistic fusion boosters don’t envisage any commercial energy production from fusion before 2050. Fusion is simply a distraction from the need to drastically reduce the use of fossil fuels, and hence greenhouse gas production, as fast as possible. There is no technological solution to that which is even remotely adequate without radical behavioural and institutional change. Pretending to yourself that there is, is as irrational as pretending to yourself that there is life after death, or a benevolent deity that will make everything come out all right.

  11. leftwingfox says

    There is no technological solution to that which is even remotely adequate without radical behavioural and institutional change.

    Agreed. I do think thorium fission and hydrogen fusion are part of the mid-term and long-term solutions respectively. Enforcing stricter energy standards and promoting superior efficiency options are doable now, as is shifting economic policy to promote green energy over fossil fuels.

  12. M Groesbeck says

    It’s looking like practical fusion might come in just a bit too late to be the seamless replacement for fossil-fuel energy. There are any number of projects (I’m a lowly research intern for one) which might dramatically shorten the development cycle for useful fusion power; unfortunately, even these would put us on a time scale where we’ll still need to do some major energy-budgeting before large-scale fusion comes online.

    (In the long run, helium-3 fusion is the goal in terms of clean energy, but that’s a bit less short-term than deuterium/tritium; give us a hundred years and we’ll be mining the moon and/or Saturn for (3)He, but that’s much too long a scale on which to be replacing fossil-fuel energy.)

  13. KG says

    I do think thorium fission and hydrogen fusion are part of the mid-term and long-term solutions respectively.

    Maybe they are, and maybe not. In advance of decades of necessary R&D, we have no way of knowing.

    Enforcing stricter energy standards and promoting superior efficiency options are doable now, as is shifting economic policy to promote green energy over fossil fuels.

    Necessary, but quite inadequate. We need radical changes in behaviour (flying only in emergency if at all, reducing long-distance travel of any kind, switching from private autos to public transport, bicycles and walking, greatly reducing meat and dairy consumption, a massive programme of home insulation, carbon rationing, cutting birthrates – chiefly by improving the status of women and girls) and institutions (either getting rid of capitalism altogether, or changing it so radically it would scarcely be recognisable as such) if we are to have any realistic chance of avoiding disaster.

    It’s looking like practical fusion might come in just a bit too late to be the seamless replacement for fossil-fuel energy. – M Groesbeck

    Well yes, if your definition of “just a bit” is “several decades at least”. We need to be reducing output of greenhouse gases now and in case you hadn’t noticed, it’s still rising rapidly.

  14. gedwarren says

    We’re sorry but this site is not accessible from the UK….

    Whaa..? I’m paying for this but I can’t see it. How about that!

  15. birgerjohansson says

    At Physorg.com they had a story about how the Z-pinch method might be useful for creating a fusion drive for inteplanetary travel.
    It will actually be much easier than terrestrial power generation: you already have a hard vacuum, you have no risk of neutrons inducing radioactivity in substances leaking out to populated areas, no big generators.

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