Is Nuclear Fusion power on Earth just an expensive pipe dream?

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RichInSpirit

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Nuclear fusion is being proclaimed as being the Holy Grail of future limitless source of "Green" power. Ok it may not release CO2 into the atmosphere but it will release vast quantities of heat into the Earth's atmosphere. Which in my book also heats up the "Greenhouse" that we live in, the Earth. In that regard it's exactly the same result as fossil fuels or nuclear fission. Releasing energy that is stored here on Earth.
We already have Nuclear Fusion power from a nice safe distance of 93 million miles away in the Sun. Renewables Solar and Wind are all Nuclear Fusion powered without adding much extra CO2 or heat to the Earth except maybe setting them up but once they are up and running no extra CO2 or heat created.
 
I'm keeping an open mind on nuclear fusion, but solar and wind have big intermittency issues. How do you keep a country going at night if there's no wind? You need nuclear or fossil fuels to fill that gap, OR you need an energy storage solution which doesn't really exist yet - either batteries on a whole level higher than we currently have, or some way to convert that energy into a chemical form that can be used without generating CO2.

Also, can you explain how wind is nuclear fusion powered?
 
If heat was just the problem I'm sure we could water cool it, even have a massive community heating scheme off the back of it (win win). Less burning, whether in a car/fireplace/furnace would seem to be the solution.
 
There's no down side to a stable nuclear fusion reactor. The "Stable" bit is the problem, even if they can crack the technology.
 

The heat is the point though - it wouldn't be released into the atmosphere but rather used to generate electricity. Same as fission reactors.
 

You could also store via kinetic / potential energy i.e. use wind power to pump and store water to higher ground and release it to generate hydro electric when required

I guess you could say that heat from the sun assists with convection currents that help drive wind - but really it is more to do with the rotation of the earth (as far as I know)
 
EmmDee said:
You could also store via kinetic / potential energy i.e. use wind power to pump and store water to higher ground and release it to generate hydro electric when required
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Someone (Spirit of Ireland) proposed this yonks ago. It's my understanding that it doesn't work, I.e. there isn't sufficient stable wind power to lift water to the reservoir. Turlough Hill is different. It was built on the assumption that there would be a nuclear plant that would pump water up in the slack periods. It's my understanding that now while wind energy does pump water up Turlough Hill, most of the pumping is powered by the national grid. (Also, Turlough Hill was built 45 years ago, when we could carry out major civil engineering projects - I wouldn't bet on it today).
 
PMU said:
It's my understanding that now while wind energy does pump water up Turlough Hill, most of the pumping is powered by the national grid.
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Coal, Oil,Gas power stations produce at the same rate all the time, whereas demand dips at night, so the use of the gris to pump Turlough Hill at night is very efficient.

PMU said:
(Also, Turlough Hill was built 45 years ago, when we could carry out major civil engineering projects - I wouldn't bet on it today).
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You are right, organised public action on any topic that involves more than producing policies and passing laws, seems to be a thing of the past.
 
EmmDee said:
The heat is the point though - it wouldn't be released into the atmosphere but rather used to generate electricity. Same as fission reactors.
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But it does get released into atmosphere, atomic energy is converted to heat which produces steam, the steam does some mechanical energy to generate electricity, but most of the energy stays as heat.
I think that's one of the theories of thermodynamics that for an energy transfer entropy must increase and that basically the lowest form of energy is heat, once everything ends up as heat you can't convert any more energy to do other stuff. So the amount of energy in the universe in the form of heat is always increasing but every other form of energy is reducing. So you can convert matter to heat in a nuclear reaction but you can never go the other way convert heat energy back to matter again. There seems to be hierarchies in nature but you can only move one way in that hierarchy.
 
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joe sod said:
for an energy transfer entropy must increase
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Yes its called the zeroth law of thermodynamics, (because there was already a well established first law of thermodynamics but the increase in entropy is seen as more fundamental).

But after that, no.

Heat can obviously be transferred into other forms of energy, when you boil the kettle, the heat evaporates the water.
 
@cremeegg in the case of the kettle, the energy was electric energy converted to heat energy which evaporates the water, that then escapes as heat when water recondenses, it's that heat that cannot be turned back into electricity, it's now in the heat soup which is basically waste energy. Of course you can use that latent heat in a heat pump for a house but you must expend more energy (electricity) to do it. Heat is obviously at the bottom of the energy hierarchy.
 
joe sod said:
Heat is obviously at the bottom of the energy hierarchy.
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Any energy transfer is less than perfectly efficient, that is why entropy must increase. That inefficiency is often seen as friction or heat. However the idea of an energy hierarchy is a new one on me.

Could noise not equally be the form the inefficiency takes.
 
I'm not anti fusion but some aspects of it scare me a bit. The 150 to 200 million degree temperatures of the plasmas in the tokamak reactors are unreal temperatures to be playing around with. Also the strong magnetic fields and the huge draw on electricity to produce the magnetic fields. And there are gamma rays produced by fusion. They say that these get reabsorbed but I don't know.
Also the efficiencies achieved so far, more energy in than energy out. The sun and stars have gravity as a natural "free" force or energy to attain the necessary temperatures and pressures for fusion. Without gravity the energy in might always be greater than the energy out.
That said I suppose the scientists have to investigate it and see if they can get it to work successfully as a power source.
 
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