Wind and wave energies are probably not renewable after all
244 replies, posted
Source : [URL="http://www.newscientist.com/article/mg21028063.300-wind-and-wave-energies-are-not-renewable-after-all.html"]New Scientist[/URL]
[quote=New Scientist] [I]Build enough wind farms to replace fossil fuels and we could do as much damage to the climate as greenhouse global warming[/I]
WITNESS a howling gale or an ocean storm, and it's hard to believe that humans could make a dent in the awesome natural forces that created them. Yet that is the provocative suggestion of one physicist who has done the sums.
He concludes that it is a mistake to assume that energy sources like wind and waves are truly renewable. Build enough wind farms to replace fossil fuels, he says, and we could seriously deplete the energy available in the atmosphere, with consequences as dire as severe climate change.
Axel Kleidon of the Max Planck Institute for Biogeochemistry in Jena, Germany, says that efforts to satisfy a large proportion of our energy needs from the wind and waves will sap a significant proportion of the usable energy available from the sun. In effect, he says, we will be depleting green energy sources. His logic rests on the laws of thermodynamics, which point inescapably to the fact that only a fraction of the solar energy reaching Earth can be exploited to generate energy we can use.
When energy from the sun reaches our atmosphere, some of it drives the winds and ocean currents, and evaporates water from the ground, raising it high into the air. Much of the rest is dissipated as heat, which we cannot harness.
At present, humans use only about 1 part in 10,000 of the total energy that comes to Earth from the sun. But this ratio is misleading, Kleidon says. Instead, we should be looking at how much useful energy - called "free" energy in the parlance of thermodynamics - is available from the global system, and our impact on that.
Humans currently use energy at the rate of 47 terawatts (TW) or trillions of watts, mostly by burning fossil fuels and harvesting farmed plants, Kleidon calculates in [URL="http://arxiv.org/abs/1103.2014"]a paper to be published in [I]Philosophical Transactions of the Royal Society[/I][/URL]. This corresponds to roughly 5 to 10 per cent of the free energy generated by the global system.
"It's hard to put a precise number on the fraction," he says, "but we certainly use more of the free energy than [is used by] all geological processes." In other words, we have a greater effect on Earth's energy balance than all the earthquakes, volcanoes and tectonic plate movements put together.
Radical as his thesis sounds, it is being taken seriously. "Kleidon is at the forefront of a new wave of research, and the potential prize is huge," says Peter Cox, who studies climate system dynamics at the University of Exeter, UK. "A theory of the thermodynamics of the Earth system could help us understand the constraints on humankind's sustainable use of resources." Indeed, Kleidon's calculations have profound implications for attempts to transform our energy supply.
Of the 47 TW of energy that we use, about 17 TW comes from burning fossil fuels. So to replace this, we would need to build enough sustainable energy installations to generate at least 17 TW. And because no technology can ever be perfectly efficient, some of the free energy harnessed by wind and wave generators will be lost as heat. So by setting up wind and wave farms, we convert part of the sun's useful energy into unusable heat.
"Large-scale exploitation of wind energy will inevitably leave an imprint in the atmosphere," says Kleidon. "Because we use so much free energy, and more every year, we'll deplete the reservoir of energy." He says this would probably show up first in wind farms themselves, where the gains expected from massive facilities just won't pan out as the energy of the Earth system is depleted.
Using a model of global circulation, Kleidon found that the amount of energy which we can expect to harness from the wind is reduced by a factor of 100 if you take into account the depletion of free energy by wind farms. It remains theoretically possible to extract up to 70 TW globally, but doing so would have serious consequences.
Although the winds will not die, sucking that much energy out of the atmosphere in Kleidon's model changed precipitation, turbulence and the amount of solar radiation reaching the Earth's surface. The magnitude of the changes was comparable to the changes to the climate caused by doubling atmospheric concentrations of carbon dioxide ([I]Earth System Dynamics[/I], [URL="http://dx.doi.org/10.5194/esd-2-1-2011"]DOI: 10.5194/esd-2-1-2011[/URL]).
"This is an intriguing point of view and potentially very important," says meteorologist Maarten Ambaum of the University of Reading, UK. "Human consumption of energy is substantial when compared to free energy production in the Earth system. If we don't think in terms of free energy, we may be a bit misled by the potential for using natural energy resources."
This by no means spells the end for renewable energy, however. Photosynthesis also generates free energy, but without producing waste heat. Increasing the fraction of the Earth covered by light-harvesting vegetation - for example, through projects aimed at "greening the deserts" - would mean more free energy would get stored. Photovoltaic solar cells can also increase the amount of free energy gathered from incoming radiation, though there are still major obstacles to doing this sustainably.
In any event, says Kleidon, we are going to need to think about these fundamental principles much more clearly than we have in the past. "We have a hard time convincing engineers working on wind power that the ultimate limitation isn't how efficient an engine or wind farm is, but how much useful energy nature can generate." As Kleidon sees it, the idea that we can harvest unlimited amounts of renewable energy from our environment is as much of a fantasy as a perpetual motion machine.
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Basically, if we somehow built the ridiculously huge number of wind turbines and wave power plants needed to power humanity, we would fuck up the weather systems of the Earth and it'd screw up a lot of other things (see article).
I always wondered if using lots of wind turbines would drain energy from the atmosphere and screw things up, turns out it might not be so far from the truth.
So basically the only good "renewable" energy is solar power, and there are still a couple of problems with that as well (solar panels giving off heat radiation which cannot escape the atmosphere, contributing to global warming).
tl;dr : we can still use these technologies, but we can't power the whole planet with them.
Solution: Use less power
[QUOTE=kaskade700;28997095]Solution: Use less power[/QUOTE]
okay, you first, get off your computer right now
Like I said, Nuclear power is our future.
Where is JDK to disagree and tell everyone to use wind/solar/wave "renewable" energies
Bullshit.
Well then, looks like nuclear power is the only way to go.
[QUOTE=Laserbeams;28997111]Bullshit.[/QUOTE]
Got a better argument?
[QUOTE=carcarcargo;28997112]Well then, looks like nuclear power is the only way to go.[/QUOTE]Fusion and/or thorium, we need to dump the uranium/plutonium ones at the earliest opportunity imo.
[QUOTE=Turnips5;28997118]Got a better argument?[/QUOTE]
It takes a lot more than a bunch of giant fans to stop wind
[QUOTE=Laserbeams;28997148]It takes a lot more than a bunch of giant fans to stop wind[/QUOTE]
lol
how do you figure that?
[QUOTE=carcarcargo;28997112]Well then, looks like nuclear power is the only way to go.[/QUOTE]
Just put all the research money into fusion :science:
Got any equations or calculations you used?
[QUOTE=Sgt Doom;28997141]Fusion and/or thorium, we need to dump the uranium/plutonium ones at the earliest opportunity imo.[/QUOTE]
Fusion and Throium are still nuclear power they just produce much less radiation. I also think we should keep plutonium as it pretty much replaces the fuel it uses.
Who is the fucker that turned off the wind?
I hope you guys aren't going to rate the article dumb because it disagrees with your preconceptions of "wind is real strong, and it keeps coming like, forever"
[QUOTE=kaskade700;28997095]Solution: Use less power[/QUOTE]
Good luck with that idea it worked so well for everyone else that tried to promote it. :downs:
[QUOTE=lemongrapes;28997163]Just put all the research money into fusion :science:[/QUOTE]
Put most of the money into the development of Thorium reactors. Fusion is many many years away. So don't count on getting it now. putting more money into it doesn't make it magically appear, this isn't a video game.
We just can't count on Wind/Solar/Wave/Coal/Oil/Gas power sources. They're expensive, dirty, and worthless sources. We should still step up on our Uranium reactors, and start introducing thorium reactors shortly.
Then toss Greenpeace and opposing hippies that are against progression into those reactor pools.
[QUOTE=Turnips5;28997214]I hope you guys aren't going to rate the article dumb because it disagrees with your preconceptions of "wind is real strong, and it keeps coming like, forever"[/QUOTE]
Admittedly his theory isn't proven so I wouldn't exactly take it too seriously
[editline]5th April 2011[/editline]
[QUOTE=Richard Simmons;28997240]Put most of the money into the development of Thorium reactors. Fusion is many many years away. So don't count on getting it now. putting more money into it doesn't make it magically appear, this isn't a video game.
We just can't count on Wind/Solar/Wave/Coal/Oil/Gas power sources. They're expensive, dirty, and worthless sources. We should still step up on our Uranium reactors, and start introducing thorium reactors shortly.
Then toss Greenpeace and opposing hippies that are against progression into those reactor pools.[/QUOTE]
Last I heard they got fusion to 60% efficiency, the only thing holding fusion back is the lack of funds.
[QUOTE=carcarcargo;28997252]Admittedly his theory isn't proven so I wouldn't exactly take it too seriously[/QUOTE]
It's not "proven", but it's not something you can just dismiss with "bullshit"
[QUOTE=kaskade700;28997095]Solution: Use less power[/QUOTE]
Better solution: Industries develop their products to use less power.
[quote]
Although the winds will not die, sucking that much energy out of the atmosphere in Kleidon's model changed precipitation, turbulence and the amount of solar radiation reaching the Earth's surface. The magnitude of the changes was comparable to the changes to the climate caused by doubling atmospheric concentrations of carbon dioxide ([I]Earth System Dynamics[/I], [URL="http://dx.doi.org/10.5194/esd-2-1-2011"]DOI: 10.5194/esd-2-1-2011[/URL]).
"This is an intriguing point of view and potentially very important," says meteorologist Maarten Ambaum of the University of Reading, UK. "Human consumption of energy is substantial when compared to free energy production in the Earth system. If we don't think in terms of free energy, we may be a bit misled by the potential for using natural energy resources."[/quote]
He's not trying to say that we can't use renewable resources, he's saying there will be profound consequences for the climate if we actually ran the whole world off them (i.e. what greenpeace want to do)
[QUOTE=carcarcargo;28997170]Fusion and Throium are still nuclear power they just produce much less radiation. I also think we should keep plutonium as it pretty much replaces the fuel it uses.[/QUOTE]I was mainly thinking in terms of safety and waste material, of which thorium and fusion are absolutely superior in every field. Plutonium would be alright with regards to fuel supply (as opposed to uranium), but tbh we should be cutting down on the nuclear waste produced at the earliest possible opportunity.
Looks like you [I]are [/I]going rate the article dumb without reading it! Well done guys
[QUOTE=Turnips5;28997162]lol
how do you figure that?[/QUOTE]
Because wind is powered by the sun heating the air, so unless we use wind energy to destroy the sun somehow, wind will keep blowing
Wind farms already dramatically alter the climate in some areas, so this seems like an inevitable consequence should we expand wind power significantly.
[QUOTE=Sgt Doom;28997330]I was mainly thinking in terms of safety and waste material, of which thorium and fusion are absolutely superior in every field. Plutonium would be alright with regards to fuel supply (as opposed to uranium), but tbh we should be cutting down on the nuclear waste produced at the earliest possible opportunity.[/QUOTE]
And thats why we should move to Thorium. Significantly less nuclear waste.
[QUOTE=Laserbeams;28997341]Because wind is powered by the sun heating the air, so unless we use wind energy to destroy the sun somehow, wind will keep blowing[/QUOTE]Think of it friction on a global scale slowing down the wind. Of course it's not going to stop wind, nobody suggested that.
[QUOTE=carcarcargo;28997252]Admittedly his theory isn't proven so I wouldn't exactly take it too seriously[/QUOTE]
Uh, it's not a theory. His calculations could be off, but it's pretty well established that if you're taking energy out of a system to use there is less in the system.
[QUOTE=Turnips5;28997118]Got a better argument?[/QUOTE]
Said Physicist is a Big Coal/Big Oil/Big Industry lackey? :v:
[QUOTE=Laserbeams;28997341]Because wind is powered by the sun heating the air, so unless we use wind energy to destroy the sun somehow, wind will keep blowing[/QUOTE]
It's not as simple as that, as the guy has shown in his models/calculations.
[quote]It remains theoretically possible to extract up to 70 TW globally, but doing so would have serious consequences.
[B]Although the winds will not die[/B], sucking that much energy out of the atmosphere in Kleidon's model changed precipitation, turbulence and the amount of solar radiation reaching the Earth's surface. The magnitude of the changes was comparable to the changes to the climate caused by doubling atmospheric concentrations of carbon dioxide[/quote]
He's specifically arguing that it won't STOP wind. It'll just affect climate patterns, precipitation and the like.
Proof that you didn't actually read any of the article.
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