Although I am member of Environmentalists For Nuclear (EFN) I suspect that it is our nuclear sponsors and Australian uranium mining who have concocted this concern of winds running out in the aftermath of Japan nuclear disaster in order to dismiss the renewables as serious alternative. In any case, it will take decades to build such capacity which should not be our immediate concern at all. Albert
Date: Sat, 2 Apr 2011 20:17:40 +0000 Subject: Re: Re: [geo] Wind and wave energies are not renewable after all From: [email protected] To: [email protected] CC: [email protected]; [email protected]; [email protected] Hi All, Last year I read a short comment by Dr. Caldera on "High Wind" energy harvesting posted on Bill Gates website http://www.thegatesnotes.com/Conversations/What-About-Wind. Dr. Caldera stated "if we were to meet future power demand by this source exclusively, we must intercept more than 1% of natural flows. I think when we get above a 1% change in a natural system, we need to be concerned about large scale unintended consequences.". And, now I see this report by Dr. Kleidon reporting concerns about Boundary Layer Winds and Wave Energy. I am somewhat disappointed that such exotic extrapolations are getting serious play on the issue of renewable energy. First, I believe Dr. Gaskill statement in this tread is the the clearest thinking on this issue of the use of these renewable energies. This planet is in fact solar powered and the solar energy that it receives is far more than we can use. Also, Boundary Layer winds are effected by the difference between the rotational speed of the planet and that of the total (fluid) mass of the atmosphere. High altitude winds also get impacted by this differential to a certain degree. Wave energy has not just the solar energy input, but, the added lunar diurnal gravitational influence. I am not an expert in any shape or form, but, I have twirled a coffee cup and watched how the "boundary friction" between the cup and fluid causes the fluid to move. And, I have stood by the shore and watched the force of a tide rise and fall and watched the wave production from that force. On a global scale, these basic physical forces are clearly significant enough to be considered into the equation. Looking beyond just the solar energy input/effect seems worth factoring into these types of calculations. We should not be looking to calculate any renewable energy option into the ground. We will need all of them (including High Wind) to power our civilization. Dr. Gaskill, when they wake you up, I'll cook breakfast! > My reading of the article suggested that the authors of the study were > principally claiming that wind has an impact on climate, so it is already > being "used". What wasn't clear from the article was what type of impact > reducing the energy level of winds all over the globe through the prolific > use of wind turbines might have. In a warming world, I understand we should > expect stronger winds. On a simplistic generalized level that might not be > relevant to local climate, slowing those stronger winds down might have an > ameliorating effect on climate change. Hence the claim that "The magnitude of > the changes was comparable to the changes to the climate caused by doubling > atmospheric concentrations of carbon dioxide" might not be as bad as it is > made to seem. > > > As usually, I'm grasping at straws, but as a layman, that's what stood out > for me. > > > Nando > > On Sat, Apr 2, 2011 at 3:15 PM, Alvia Gaskill [email protected]> wrote: > > > > > > > > > Wind and wave energy are the result of the conversion of > solar energy into kinetic energy, i.e. the motion of molecules. Once > converted into kinetic energy it's a use it or lose it proposition. > Extracting kinetic energy from the atmosphere or the ocean doesn't mean it > won't > be replaced by more energy from sunlight. Planting more trees will also > intercept winds, albeit without the electricity generation. Who funded > this research? The same people who want to prevent contact with alien > civilizations? I note that the Royal Society was also a party to that one > too. Note to Royal Society. When you actually find something under > the bed I should be afraid of, wake me up. > > > > ----- Original Message ----- > > From: > Andrew Lockley > > To: geoengineering > > Sent: Friday, April 01, 2011 8:10 > > Subject: [geo] Wind and wave energies are > not renewable after all > > > > > > Wind > and wave energies are not renewable after all > > > 30 > March 2011 by Mark > Buchanan > Magazine > issue 2806. Subscribe > and save > For > similar stories, visit the Energy > and Fuels and Climate > Change Topic Guides > > > > > > > Editorial: "The > sun is our only truly renewable energy source" > > Build > enough wind farms to replace fossil fuels and we could do as much damage to > the climate as greenhouse global warming > > 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 a paper to be published > in Philosophical > Transactions of the Royal Society. 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 (Earth > System Dynamics, DOI: > 10.5194/esd-2-1-2011). > > "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 (see > "Is solar electricity the answer?"). > > 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. > > > Is solar electricity the answer? > > > A > solar energy industry large enough to make a real impact will require cheap > and efficient solar cells. Unfortunately, many of the most efficient of > today's thin-film solar cells require > rare elements such as indium and tellurium, whose global supplies could be > depleted within decades. > > For > photovoltaic technology to be sustainable, it will have to be based on > cheaper > and more readily available materials such as zinc and copper, says Kasturi > Chopra of the Indian Institute of Technology, New Delhi. > > Researchers > at IBM showed last year that they could produce solar cells from > these elements along with tin, sulphur and the relatively rare > element selenium. These "kesterite" cells already have an efficiency > comparable with commercially competitive cells, and it may one day be > possible > to do without the selenium. > > Even > if solar cells like this are eventually built and put to work, they will > still > contribute to global warming. That is because they convert only a small > fraction of the light that hits them, and absorb most of the rest, converting > it to heat that spills into the environment. Sustainable solar energy may > therefore require cells that reflect the light they cannot > use. > > > > > > -- > You received this message because you are subscribed to the > Google Groups "geoengineering" group. > To post to this group, send email to > [email protected]. > To unsubscribe from this group, send email > to [email protected]. > For more options, visit > this group at > http://groups.google.com/group/geoengineering?hl=en. > > > > > > > > > > -- > > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > [email protected]. > > > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > > > > > > > > > -- > Nando M. Breiter > The CarbonZero Project > CP 234 > 6934 Bioggio > Switzerland > > +41 91 606 6372 > > [email protected] > > www.carbonzero.ch > > > > > > > > -- > > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > [email protected]. > > > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > > > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. 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