"Wind and wave energy are not renewable after all"
Spoiler
There was an article in NewScientist last week about a hypothesis that Wind and wave energy could be as damaging to our planet as fossil fuels. If you don't want to read through the full article (in Spoilers), then essentially the problems stems from applying the Laws of Thermodynamics to renewable energy generation. There is only a limited supply of "free energy" (energy which can be used to do work- work such as the movement of air to create winds) in our planet which gets replaced continuously by the Sun. If a lot of additional free energy is used up by Wind/Wave turbines and dissipated as waste heat (unusable energy), that could cause serious trouble to our planet's balance.
What do you guys think of this? Is it just another hypothesis that will never go anywhere, or could this mean some serious problems for the renewable energy industry?
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I accept this theory. Back to the nuclear band wagon we go!
It's a very interesting theory, although one I don't really understand 
Original post by Student2806
It's a very interesting theory, although one I don't really understand
I really struggled to understand it too. This hypothesis is based on lots of calculations (and perhaps climate modelling), so it's pretty hard to understand conceptually.
Here's my attempt to grasp it. Thermodynamic free energy is basically the energy that you can use to do "work"- work is a mechanical process such as the movement of air in winds. The petrol in a car engine is high in free energy, because it can do work and propel the car. The waste heat that your car dissipates from burning petrol on the other hand is low in free energy, as you cannot use this waste heat to propel a car. Free energy is NOT conserved. The Earth has a certain amount of free energy because the Sun heats the Earth unequally, causing differences in air pressure on the Earth. Since a system always tries to equalise pressure, this causes winds (and by extension waves) to be produced.
When the wind blows normally, work is being done, which results in a loss of free energy. Now this is fine normally, because the Sun will continue to heat up the Earth unequally and replaces the free energy of the Earth. However, if you do try to extract further work by having the wind generate electricity in wind turbines, that reduces the free energy in the system, so there is less available energy for the Earth to do work and produce winds.
Essentially, the presence of too many wind turbines means we drain free energy from the winds at a rate faster than this free energy is replenished by the Sun. Hence the headline of the article that wind energy might not be so renewable after all.
(edited 13 years ago)
Original post by innerhollow
I really struggled to understand it too. This hypothesis is based on lots of calculations (and perhaps climate modelling), so it's pretty hard to understand conceptually.
Here's my attempt to grasp it. Thermodynamic free energy is basically the energy that you can use to do "work"- work is a mechanical process such as the movement of air in winds. The petrol in a car engine is high in free energy, because it can do work and propel the car. The waste heat that your car dissipates from burning petrol on the other hand is low in free energy, as you cannot use this waste heat to propel a car. Free energy is NOT conserved. The Earth has a certain amount of free energy because the Sun heats the Earth unequally, causing differences in air pressure on the Earth. Since a system always tries to equalise pressure, this causes winds (and by extension waves) to be produced.
When the wind blows normally, work is being done, which results in a loss of free energy. Now this is fine normally, because the Sun will continue to heat up the Earth unequally and replaces the free energy of the Earth. However, if you do try to extract further work by having the wind generate electricity in wind turbines, that reduces the free energy in the system, so there is less available energy for the Earth to do work and produce winds.
Essentially, the presence of too many wind turbines means we drain free energy from the winds at a rate faster than this free energy is replenished by the Sun. Hence the headline of the article that wind energy might not be so renewable after all.
Here's my attempt to grasp it. Thermodynamic free energy is basically the energy that you can use to do "work"- work is a mechanical process such as the movement of air in winds. The petrol in a car engine is high in free energy, because it can do work and propel the car. The waste heat that your car dissipates from burning petrol on the other hand is low in free energy, as you cannot use this waste heat to propel a car. Free energy is NOT conserved. The Earth has a certain amount of free energy because the Sun heats the Earth unequally, causing differences in air pressure on the Earth. Since a system always tries to equalise pressure, this causes winds (and by extension waves) to be produced.
When the wind blows normally, work is being done, which results in a loss of free energy. Now this is fine normally, because the Sun will continue to heat up the Earth unequally and replaces the free energy of the Earth. However, if you do try to extract further work by having the wind generate electricity in wind turbines, that reduces the free energy in the system, so there is less available energy for the Earth to do work and produce winds.
Essentially, the presence of too many wind turbines means we drain free energy from the winds at a rate faster than this free energy is replenished by the Sun. Hence the headline of the article that wind energy might not be so renewable after all.
Does that mean hypothetically we could stop all wind and waves by using up all free energy in the Earth energy system?
Original post by therealOG
Does that mean hypothetically we could stop all wind and waves by using up all free energy in the Earth energy system?
Well wind/wave turbines aren't 100% efficient so no you couldn't stop wind/waves altogether. However, according to this article, wind/wave energy could cause long-term decreases in wind/wave speed (causing far less electricity than expected to be produced) and various climate instabilities.
(edited 13 years ago)
Why don't Christians, Muslims etc. simply pray for energy ?
Original post by CoolDude
"Wind and wave energy are not renewable after all"...so are they variably renewable or semi-renewable?
Think of Wind/Wave energy as a bucket.
We can take some water out of the bucket and it will be continually refilled and so there will be no real affect on the system (the bucket).
However if we start taking water out of the bucket at a massive rate then the natural refilling of the bucket will not be able to keep up, and there will be a macroscopic change on the system.
It is renewable in that it will always (ignoring what's going to happen in a few billion years time) be renewed, but if we take too much of the energy then it will have massive effects on our planet, which obviously doesn't sound too good.
I would be interested if they have made similar studies into the effects of Nuclear Fusion power.
For those who don't know, fusion would basically be infinite in that a tiny about of Hydrogen (which we can make as much as we like of) will produce, using the technical term, a **** load of energy.
That said, if we want 20-30TW of electrical power, that means producing 100-150TW of heat energy from fusion. This is heat that would otherwise never be released into the system (fusion does not occur naturally on Earth), and would normally remain safely tied up as mass.
So, what is the effect of producing an extra 100-150TW of heat in our system? Is that enough to change our planet as a whole?
I bloody hope someone has asked this question high up, because clearly they didn't think through Wind power that thoroughly.
As a side note, Fission is definitely not the way forward in the long term because, contrary to popular belief, there is not actually that much fissionable material out there. Less than 100 years of Uranium at current consumption (which is set to sky-rocket), although I don't know how much of the other materials we could use we have left.
Original post by Fallen
Think of Wind/Wave energy as a bucket.
We can take some water out of the bucket and it will be continually refilled and so there will be no real affect on the system (the bucket).
However if we start taking water out of the bucket at a massive rate then the natural refilling of the bucket will not be able to keep up, and there will be a macroscopic change on the system.
It is renewable in that it will always (ignoring what's going to happen in a few billion years time) be renewed, but if we take too much of the energy then it will have massive effects on our planet, which obviously doesn't sound too good.
I would be interested if they have made similar studies into the effects of Nuclear Fusion power.
For those who don't know, fusion would basically be infinite in that a tiny about of Hydrogen (which we can make as much as we like of) will produce, using the technical term, a **** load of energy.
That said, if we want 20-30TW of electrical power, that means producing 100-150TW of heat energy from fusion. This is heat that would otherwise never be released into the system (fusion does not occur naturally on Earth), and would normally remain safely tied up as mass.
So, what is the effect of producing an extra 100-150TW of heat in our system? Is that enough to change our planet as a whole?
I bloody hope someone has asked this question high up, because clearly they didn't think through Wind power that thoroughly.
As a side note, Fission is definitely not the way forward in the long term because, contrary to popular belief, there is not actually that much fissionable material out there. Less than 100 years of Uranium at current consumption (which is set to sky-rocket), although I don't know how much of the other materials we could use we have left.
We can take some water out of the bucket and it will be continually refilled and so there will be no real affect on the system (the bucket).
However if we start taking water out of the bucket at a massive rate then the natural refilling of the bucket will not be able to keep up, and there will be a macroscopic change on the system.
It is renewable in that it will always (ignoring what's going to happen in a few billion years time) be renewed, but if we take too much of the energy then it will have massive effects on our planet, which obviously doesn't sound too good.
I would be interested if they have made similar studies into the effects of Nuclear Fusion power.
For those who don't know, fusion would basically be infinite in that a tiny about of Hydrogen (which we can make as much as we like of) will produce, using the technical term, a **** load of energy.
That said, if we want 20-30TW of electrical power, that means producing 100-150TW of heat energy from fusion. This is heat that would otherwise never be released into the system (fusion does not occur naturally on Earth), and would normally remain safely tied up as mass.
So, what is the effect of producing an extra 100-150TW of heat in our system? Is that enough to change our planet as a whole?
I bloody hope someone has asked this question high up, because clearly they didn't think through Wind power that thoroughly.
As a side note, Fission is definitely not the way forward in the long term because, contrary to popular belief, there is not actually that much fissionable material out there. Less than 100 years of Uranium at current consumption (which is set to sky-rocket), although I don't know how much of the other materials we could use we have left.
You're not taking into account resource exploration. 80 years reserves is our assured uranium supply at present, that number will rise as countries start looking for more uranium! Moreover, improvements in nuclear energy technology further increase our fission economy, such as breeder reactors to reprocess spent fuel, and new lines of reactors which can use different fuels (i.e. thorium fission reactors).
I don't think fission is a long-term solution to be fair, because it's still non-renewable, but certainly until we are able to implement a long-term feasible renewable energy solution (which we don't really have at the moment), we are rather stuck for options. And as countries like France have demonstrated, switching a large proportion of your energy production to nuclear in a short space of time is manageable.
The waste heat from Fusion would cause Climate Warming, yes.
(edited 13 years ago)
Original post by innerhollow
You're not taking into account resource exploration. 80 years reserves is our assured uranium supply at present, that number will rise as countries start looking for more uranium! Moreover, improvements in nuclear energy technology further increase our fission economy, such as breeder reactors to reprocess spent fuel, and new lines of reactors which can use different fuels (i.e. thorium fission reactors).
I don't think fission is a long-term solution to be fair, because it's still non-renewable, but certainly until we are able to implement a long-term feasible renewable energy solutio (which we don't really have at the moment), we are rather stuck for options.
The waste heat from Fusion would cause Climate Warming, yes.
I don't think fission is a long-term solution to be fair, because it's still non-renewable, but certainly until we are able to implement a long-term feasible renewable energy solutio (which we don't really have at the moment), we are rather stuck for options.
The waste heat from Fusion would cause Climate Warming, yes.
It is very, very dangerous to start building dozens of multi-billion pound Fission reactors in the [I]hope[\I] that our (generally fairly good) estimates are wrong.
You must also factor in the cost of establishing Uranium supply-lines, pre- and post- fission processing plants, and long term waste storage facilities.
All in all there is a lot of expense which may be worth it, but we'd better be pretty dam'n sure before we place trillions or pounds and our energy security in it.
True, other fuels are also viable, but as I suspect you are aware the processes involved in, say, a thorium reactor are completely different, and large parts of a Uranium power station would be left both redundant and require substantial modification and replacement to convert it.
In addition, Uranium power stations have very specific requirements for their waste processing plants, which would be rendered useless even if we converted all old Uranium power stations to other fuels after the Uranium is depleted.
Yes, it would cause Climate Change, but do you or anyone else have any idea how much ~100TW is? It is evidently a lot, but the Earth could be radiating it away with ease. I don't know...
[QUOTE="Fallen;30737345"]It is very, very dangerous to start building dozens of multi-billion pound Fission reactors in the hope[\I] that our (generally fairly good) estimates are wrong.
You must also factor in the cost of establishing Uranium supply-lines, pre- and post- fission processing plants, and long term waste storage facilities.
All in all there is a lot of expense which may be worth it, but we'd better be pretty dam'n sure before we place trillions or pounds and our energy security in it.
True, other fuels are also viable, but as I suspect you are aware the processes involved in, say, a thorium reactor are completely different, and large parts of a Uranium power station would be left both redundant and require substantial modification and replacement to convert it.
In addition, Uranium power stations have very specific requirements for their waste processing plants, which would be rendered useless even if we converted all old Uranium power stations to other fuels after the Uranium is depleted.
Yes, it would cause Climate Change, but do you or anyone else have any idea how much ~100TW is? It is evidently a lot, but the Earth could be radiating it away with ease. I don't know...
It's pointless to outline the problems associated with fission on an individual basis. Any global energy solution will be horrificially expensive and have a multitude of associated problems. No one said that fission is problem-free, just that it's preferable to the possible alternatives- it's the least of many evils.
Also, assured reserves are completely different to total reserves. Assured reserves are NOT an estimate or a prediction. You're also forgetting that depleted Uranium is still a possible fuel.
You must also factor in the cost of establishing Uranium supply-lines, pre- and post- fission processing plants, and long term waste storage facilities.
All in all there is a lot of expense which may be worth it, but we'd better be pretty dam'n sure before we place trillions or pounds and our energy security in it.
True, other fuels are also viable, but as I suspect you are aware the processes involved in, say, a thorium reactor are completely different, and large parts of a Uranium power station would be left both redundant and require substantial modification and replacement to convert it.
In addition, Uranium power stations have very specific requirements for their waste processing plants, which would be rendered useless even if we converted all old Uranium power stations to other fuels after the Uranium is depleted.
Yes, it would cause Climate Change, but do you or anyone else have any idea how much ~100TW is? It is evidently a lot, but the Earth could be radiating it away with ease. I don't know...
It's pointless to outline the problems associated with fission on an individual basis. Any global energy solution will be horrificially expensive and have a multitude of associated problems. No one said that fission is problem-free, just that it's preferable to the possible alternatives- it's the least of many evils.
Also, assured reserves are completely different to total reserves. Assured reserves are NOT an estimate or a prediction. You're also forgetting that depleted Uranium is still a possible fuel.
(edited 13 years ago)
Original post by innerhollow
It's pointless to outline the problems associated with fission on an individual basis. Any global energy solution will be horrificially expensive and have a multitude of associated problems. No one said that fission is problem-free, just that it's preferable to the possible alternatives- it's the least of many evils.
Also, assured reserves are completely different to total reserves. Assured reserves are NOT an estimate or a prediction. You're also forgetting that depleted Uranium is still a possible fuel.
Also, assured reserves are completely different to total reserves. Assured reserves are NOT an estimate or a prediction. You're also forgetting that depleted Uranium is still a possible fuel.
Oh, I didn't realise it was 80 years of assured reserves, yes I know the difference.
Even so. I mean, I am all for Uranium fission, but I certainly don't think rolling out many dozens of new stations globally is going to help anyone.
Saying there isn't any point of listing the problems with Uranium isn't really true. I never said other sources were perfect, Christ no, but that doesn't mean that some solutions are better than others.
I don't suggest we do away with Uranium power, I don't even suggest we reduce our current usage. I just disagree with the opinion that Uranium 'is the answer' to all our fossil fuel based problems - because such an opinion (and I am not saying it is your opinion) is very short-sighted indeed.
Uranium plays and will play an increasing important role, but I would much prefer building more tidal barrages (like the one the last government decided to scrap plans for to 'save the wetlands' - Ignoring what's going to happen when we strip-mine for coal, uranium, and tar sands), some wind, some solar (although perhaps not in the U.K).
Saying 'Oh lets have a selection' really does sound idealistic, but then again there is no real reason why we shouldn't.
"Green" industry lobby: "QUICK, SILENCE THIS REPORT IMMEDIATELY!!"
It's true. Expect not to hear any more of it for 20 years.
It's true. Expect not to hear any more of it for 20 years.
Original post by Liquidus Zeromus
"Green" industry lobby: "QUICK, SILENCE THIS REPORT IMMEDIATELY!!"
It's true. Expect not to hear any more of it for 20 years.
It's true. Expect not to hear any more of it for 20 years.
Indeed, but what will be annoying now is politicians will still be committed to green technology and say they are doing so on the basis of science. But when said science doesn't support that view, they just ignore it or discredit the report.
It's a disgusting way to go about the energy provision of our country.
Original post by Fallen
Oh, I didn't realise it was 80 years of assured reserves, yes I know the difference.
Even so. I mean, I am all for Uranium fission, but I certainly don't think rolling out many dozens of new stations globally is going to help anyone.
Saying there isn't any point of listing the problems with Uranium isn't really true. I never said other sources were perfect, Christ no, but that doesn't mean that some solutions are better than others.
I don't suggest we do away with Uranium power, I don't even suggest we reduce our current usage. I just disagree with the opinion that Uranium 'is the answer' to all our fossil fuel based problems - because such an opinion (and I am not saying it is your opinion) is very short-sighted indeed.
Uranium plays and will play an increasing important role, but I would much prefer building more tidal barrages (like the one the last government decided to scrap plans for to 'save the wetlands' - Ignoring what's going to happen when we strip-mine for coal, uranium, and tar sands), some wind, some solar (although perhaps not in the U.K).
Saying 'Oh lets have a selection' really does sound idealistic, but then again there is no real reason why we shouldn't.
Even so. I mean, I am all for Uranium fission, but I certainly don't think rolling out many dozens of new stations globally is going to help anyone.
Saying there isn't any point of listing the problems with Uranium isn't really true. I never said other sources were perfect, Christ no, but that doesn't mean that some solutions are better than others.
I don't suggest we do away with Uranium power, I don't even suggest we reduce our current usage. I just disagree with the opinion that Uranium 'is the answer' to all our fossil fuel based problems - because such an opinion (and I am not saying it is your opinion) is very short-sighted indeed.
Uranium plays and will play an increasing important role, but I would much prefer building more tidal barrages (like the one the last government decided to scrap plans for to 'save the wetlands' - Ignoring what's going to happen when we strip-mine for coal, uranium, and tar sands), some wind, some solar (although perhaps not in the U.K).
Saying 'Oh lets have a selection' really does sound idealistic, but then again there is no real reason why we shouldn't.
No I concur. Relying 100% on one energy source is never the answer. Fission will inevitably play a huge part in our energy future, as will renewables and possibly CCS-equipped fossil fuels. However, at the moment if we want to severely reduce our fossil fuel intake, the only one of these that can be expanded in a reasonable timeframe is fission. Neither renewables nor CCS can be implemented on a large enough scale at present. That's why people view it as the "answer". I don't think anyone's said we shouldn't keep investing in renewables.
(edited 13 years ago)
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