Although the return on building new turbines would eventually plateau, that point, which they dubbed saturation wind power potential, won't be reached until there are more turbines than will be needed. That saturation point is more than 250 terawatts, which would require 100-meter-tall wind turbines covering the planet's land and water surfaces.
"We're not saying, 'Put turbines everywhere,' but we have shown that there is no fundamental barrier to obtaining half or even several times the world's all-purpose power from wind by 2030," said Jacobson in a press release. "The potential is there, if we can build enough turbines."
The researchers estimated that half the world's energy needs in 2030 would take about 5.75 terawatts. To figure out how many turbines would be required to meet that amount, the team looked at different scenarios of fixed wind power potential, or the maximum power that can be extracted using a specific number of wind turbines. They found that 4 million 100-feet-high turbines, each producing 5 megawatts, could supply as much as 7.5 terawatts of power, with no significant effect on the world's climate. If half were sited on water, and half sited on land, they would occupy about one-half of 1 percent of the planet's land surface.
Funding for the study came from the National Science Foundation, the US Environmental Protection Agency, and the National Aeronautics and Space Administration High-End Computing Program.
Ann, this is an interesting study. The issue, of course, is reliability. Will the power be there when you need it? Wind and solar, and many other new and environmentally friendly forms of power generation, are opportunistic sources. They work today because they are adjunct to our traditional base load generation capability. To really utilize these sources we would have to redesign our whole power infrastructure. This can be done, and might have some good consequences. On the other hand, we know we can deliver reliable power with the current architecture. The required transition is massive. It is much more complex than installing wind turbines.
Thanks, Lou. The study took into account wind variability, and calculated that for each turbine, as we mention. I think there are several issues here, but the reliability you mention has to do with either energy storage, a different topic, or how closely spaced turbines are to their neighbors, not with whether there's enough total wind power. Assuming the math is correct and the model is accurate, the study has shown that there is, and that was its purpose. I agree that we need to redesign our energy infrastructure and that it will be a massive transition. Alternate forms of energy are being used today only as adjuncts because they have to be, based on the generation and distribution infrastructure's current design and implementation.
I believe the extrapolations of power estimates by the researchers, and embrace the idea that harnessing the wind “everywhere” would indeed provide their claimed totals. But “everywhere” includes smack in the middle of the deepest oceans, thousands of miles from land, causing two engineering challenges. One, stability of the turbine (floating, or fixed) and Two, transmitting the harvested power from source to destination. While those might seem to be staggering obstacles, they’re no more challenging than it was to create any of our current infrastructures (cellular, power lines, roadways, railways, etc.) when they were first conceived.
Jim, I think your point is well taken about what it took to create the existing infrastructure: we managed to do that one, why not this one? Regarding location, as the article states, the researchers weren't suggesting that we put turbines everywhere. They made that assumption for mathematical purposes when calculating total power available. Once they found that total power available was way more than needed, they tested several scenarios. They propose that turbines could be placed half on land and half in the ocean, primarily in near-shore and offshore locations.
I agree, naperlou. The transition is a gargantuan engineering challenge. For now, the national labs and Electric Power Research Institute are saying that the challange will start when we reach 20% renewables. This is the first time, though, in which I've seen someone examine whether we have enough available wind on earth to make the dream happen. Great story, Ann.
I disagree, it won't be a huge challenge as utilities already solve this every day. Look at demand variability, which is basically the same thing as supply variability. Yet they easily handle that every day by a factor of 5 many times from low demand to peak.
Next hydro, new NG units that can vary/throttle 50% power with good eff coupled with demand control especially once EV's are widespread, this gets rather easy and can be done with cellphone links.
What happens when a 1Gw nuke scrams? It happens all the time cuting 1Gw from the grid yet rarely is there a blackout. 50 or so of these/yr judging from the reports in PennEnergy which tracks energy of all forms. If you were really concerned these would be far more problematic than WT's as they ramp up and down even in close, dense windfarms.
We already have $1/kwhr/yr storage using lead or molten salts, yet where are they? Facts are they are not needed.
Best by far wind isn't wind farms, which really are investment vehicles first, energy sources are a byproduct, but in home, building size units which make/save retail electric costs which are 2-3x's what a utility pays because of utility markup.
Plus as these are very spread out they never all go down but instead average nicely.
An example a 13' dia WT puts out about 10-40kwhrs/day and lighter, more simple than a moped in many places. No reason these can't be made, installed for under $2k/kw and last 50 yrs or so if done right. And that's all an eff home needs.
For big wind along the east coast match the A/C loads near perfectly. As the land warms up, the seabreeze picks up the power does too. Solar does this too making it more valuable than steady power like nukes that can't be turned off. Yet they don't pay what it's really worth they pay other Time of Day/peak sources.
Most of the misinformation has been spread by big coal trying to hang on to their rapidly decreasing power share now down to 32% from 60% and others who know little about how a grid works.
@Jerry - I agree that managing/brokering power is a common practice – actually routine to the big electric companies; I have a friend who manages the grid at FLORIDA POWER & LIGHT & he told me they re-rout GigaWatts along trunk-lines as far away as Tennessee & Ohio. It's a daily occurrence.
Jerry raises an interesting point I also keep wondering about: why the heck don't we have much better small-scale--house- or store-sized, for example--wind generation units? I think the answer should be pretty obvious: utilities as middlemen. The utilities fought tooth and nail for 30 years or so to prevent homes from generating their own solar power.
Congress over the last 10 yrs has put up laws for a free market in energy but Repubs have blocked it every time. They actually pay PR firms to have people posts on list like this one to keep new competition down like RE especially as RE is widely spread and they can't profit from it as it takes their customers away and they enjoy huge subsidies.
Between costs of coal, oil pollution, protecting international oil companies, dictatotrs for free, oil wars, etc costs to the taxpayer, IE you, me is $1T/yr in increased taxes. And they don't want to give up those subsidies by paying the real, full cost. Repubs use to say they were for full cost accounting but stopped when they found out it showed how bad their policies are when audited.
Here in Fla they are making ratepayers pay for new nuke plants 10 yrs in advance of them making power. hey make money on it even if they never make any power from them!! Yet it's illegal here to sell electicity from any source or to anyone, not even selling power to charge EV's!!!
This has stopped 30k jobs just in solar in Fla alone. Until we take US/Fla congress back from the corporatists/repubs it's not going to happen here.
I repeat myself because it is important. There is no difference between the Republicans and Democrats. Both parties are in it for themselves and not the country. That is why George Washington in his farewell address warned us about political parties and their destructive ends.
I think the wind thing has problems on a large scale. I think the small scale might just fit the bill for most people, and lower the bill considerably. But it will take some clever engineering on the blade thing to make it work.
I didn't mean to stir Jerry up. It just comes naturally. Sorry, Jerry!
I think the phrase "without regard to societal, environmental, climatic or economic considerations" is key. "One-half of 1 percent of the planet's land surface" sounds small, until you realize just how big the total land surface of the earth is.
The earth has about 150,000,000 square kilometers of land, so 0.5% of that is 750,000 square kilometers (about 185,000,000 acres). To put this in perspective, this is nearly 5 times more than the total paved area of the United States.
The societal, environmental, climatic, and economic costs of covering this much land area with wind turbines would be huge.
While this study does show that it would be possible to meet all of the world's energy needs using wind power, it also suggests why that it is unlikely to happen in reality. That being said, wind power could provide a larger fraction of the world's total energy than it currenty does.
Folks, I already clarified that "without regard to..." etc. about turbine placement had to do with the initial model building, not suggested placement of turbines. As the article states, the researchers weren't suggesting that we put turbines everywhere. They made that assumption for mathematical purposes when calculating total power available. Once they found that total power available was way more than needed, they tested several scenarios. They propose that turbines could be placed half on land and half in the ocean, primarily in near-shore and offshore locations. We state this in the article.
@Ann: You're right that the study doesn't propose putting turbines everywhere. As the study shows, putting wind turbines everywhere would easily meet the world's energy needs many times over.
But in order to meet the more modest goal of supplying 50% of the world's 2030 energy needs, and assuming that half of the turbines go on land and half in the ocean, the study's authors still propose dedicating 0.5% of the total land area of the earth to wind turbines. That's a lot of land (185 million acres).
In order to do this, they call for building 4 million 5 MW wind turbines. At $10 million each, this is a $40 trillion capital investment.
Don't get me wrong; I think the study shows that we could generate a lot more energy from wind than we currently are. But it also points to some of the limitations of wind power.
Dave, I agree with you and Warren that the economics and financing of wind turbines, including making a viable business model, is a whole different set of problems. BTW, where did you get the $10 million figure?
@Ann: According to this wind industry website, commercial wind turbines cost between $1.2 million and $2.6 million per megawatt of nameplate capacity. So I figure a 5 MW wind turbine should cost around $10 million.
I agree with Jerry that it's not obvious why 2 million wind turbines (i.e. the half of the 4 million that would be on-shore) should require 185 million acres of land. On the other hand, the press release notes (as Jerry does) that "virtually none of this area would be used solely for wind, but could serve dual purposes such as open space, farmland, ranchland or wildlife preserve."
Dave, thanks for that source. Your cost estimate is therefore on the high end. Regarding land space, the researchers say, as does my article, that 7.5 TW could be produced on about 0.05% of the planet's land surface. Note that a) that's 150% of what they estimate is needed and b) the word is "could" not "must" be located on the given area. Their point is how relatively little area it is. To your point, that much land is probably needed because a) turbines are usually grouped together in farms and those farms can't be contiguous, and b) as you note, the land can also serve dual purposes.
Dave Palmer obviously you don't or don't want to understand this land use. Wind takes little land, only 100'x100'/large turbine at the most. The land is still available for farming, fishing, mining, and most anything else one needs.
The amount of land mentioned is for spacing large turbine apart, not that it needs to exclusively for WT's. It's things like this propaganda used by big energy to keep other energy sources they can't control from happening.
Next on WT's affecting the climate is another piece of propaganda as it has as much effect as a hill. The amount of power taken from the atmospheic winds is probably 1/1,000,000,000 % if 50% of world power came from wind. That is fa, far, far, far, far less than the effects of foosil fuels on the climate.
Wind is a great energy source but only one of many we'll need. For normal people having their own energy source like wind, solar, CSP, biomass CHP, tidal/river generators, NG to keep oil prices reasonable as they dwindle and stop coal from it's massive damage, costs or we can be like China polluting ourselfs to death. It also insulates from energy price spikes.
I'm old enough to remember even Repubs, back when they had some, came to their senses and passed the EPA bill under Nixon because many of our cities became unlivable from pollution then with smog so bad many were dying, our waters so polluted some even caught fire which was the last straw along with birds dying off from pesticides, etc. Do you really want to go back to that?
Dave, 4 million turbines only need at most 4 million acres or 6400sq miles. Saying otherwise is just not true. Just because they need spacing doesn't mean they use that space inbetween.
Nor is $40T that much for that much power as it would cost as much to build other sources.
But neither will ever be done so rather a moot point.
You are correct that it's most low NG costs that is killing coal as it's not only cheaper/btu but far cheaper to transport or burn. Plus NG plants are about 60% eff now vs only 40% eff for coal. So NG can be 2x's the BTU cost of coal and still be cheaper/kwhr.
But utilities also see the writing on the wall that they'll have to pay the full cost of coal including it's socialized/taxpayers cost of the damage it does. So while NG price is responcable for the present drop in coal from 60% of generation 5 yrs ago to 32% in july it's the pollution costs that will keep it dropping.
Warren, I do know what facism is , it's a cabal between right wing gov and business taking over, controlling the government powers. And it's Repubs, big business that is doing it, not democrats. Trying to call Dems and repubs the same strains credibility, yours.
Just because Dems try to force business to stop hurting, killing people, stealing their money, etc by regulations doesn't make them facist, in fact the opposite.
I agree that parties have way too much power and the best way to curb it is open primaries so they can't control which canidates we have to vote for. If we had that then only moderate ones would win instead of the far right, l;eft ones though hard to call most dems in office far left as most are moderates.
GohperT wind and solar Feed in rates are justified as they don't have the other massive socialized costs coal especially has. Also solar happens when needed most so is actually 2-3x's more valuable that steady power like nuke, coal. So really it should get even higher FI rates. As should wind on the east coast which also happens at peak Time of Day rates.
I should admit here that wind only has a 30-40% cap output average to be honest which increases it'sinstalled cost that much but even with that higher cost it's lower running costs make it worthwhile.
That said anyone who wants 1,000 2kw home, building sizes I can make them for $750/kw wholesale with 100% profit. Remember we perfected this size WT's in the 30's!!! Many are still running 80 yrs later if maintained.
Admiral Byrd's Artic base camp one is still being used after replacing the bearings, blades and brushes and is now saving a lot of diesel costing $10/gal to ship in that is that old. I'm just doing a similar one with the improved materials I expect to last as long.
The article does mention one of the concerns about wind power in regards to altering of climate and wind turbulence and speed. This would be one of my main concerns. The Colorado River used to pour extreme amounts of water into the Gulf of California. Now after multiple dams and water usage projects, the river trickles into the Gulf and sometimes dries up before reaching its natural end. Hopefully this does not happen to our wind usage.
I like the cautionary tale of the Colorado River. I think the main innovation here is the ability to provide such a detailed computer model on a global scale. This should have significant ramifications for weather modeling. On a related note, just about any one of the currently popular renewables could probably claim to solve the world's energy needs. Add up all the sunshine that falls on earth each day. Even with modest recovery - I'll bet our energy needs are covered. Likely you'd get a similar result examining wave, tidal or sea current power. As many have noted, energy shortage isn't the issue it's energy distribution.
Renewable energy sources are widely distributed and much less concentrated than current point-sources (Steam). The payback on building the infrastructure necessary for a widely distributed low density power grid is less than marginal at present day tolerable rates. I agree, the problem isn't generation, it is distribution.
I like the question about turbulence and redirecting currents. Have there been any studies on what happens when that much wind energy is harvested? The resource looks bottomless, but energy isn't free and some of that energy may be needed for the weather engine to spin properly.
@Tim- you know, that was a point in the article I really did not understand -- how excessive turbines could affect the climate. Your example of damming the Colorado River made sense as it restricted water flow, but I need some more schooling on how excessive windmills would affect the climate. Who has a layman's explanation-?
If a wind turbine is 100% efficient (which they are not, of course), you could stand downwind from the turbine and light a match, and it would stay lit. The turbine would absolutely and completely "kill" the wind. A 5MW wind turbine is absorbing at least 5MW from the energy in the atmosphere. Is that a big amount? I haven't done the calculations, but I have to think that very large scale implementations, absorbing GW's of power from the atmosphere has to have some effect on atmospheric conditions.
Maybe Jerry is right, and it is 1/100000000000000000 of a %, but I think it would be more significant than that.
Measuring wind turbine efficiency vs. absolute numbers is like measuring solar on absolute efficiency - neither calculation represents the real benefit.
I disagree with your assumption that a 100 percent efficient turbine would not allow your match to do out. The incoming wind occupies space (volume) so the air behind the turbine does have to be removed before new wind can blow through the turbine. Therefore, the basis for efficiency measurements is not well defined (that I understand to this point - maybe someone else has done the calculations.
The real measure (or question) is, does wind power provide an economically viable option vs. current available options. If so, then all other options should be exhausted to the point where prices increase on a limited commodity until wind does become a viable option. Research should be done in advance to make sure that wind is available as a technically feasible option for consideration long before it is economically viable.
As long as government subsidies and feed-in rules penalize other generation methods and solar gets priority for capacity utilization during sunny hours (over coal), the real technical and economical feasiblity is not fairly valued.
SO in one sentence, the "risk" is thought to be that excessive Wind Turbines would absorb too much natural wind, and our climate would be left without natural air-flow. Well, If that's the scientific "down-side" then bring on the windmills, because that's not going to happen!
There's always potential for other unintended consequences. Let mechanical vibrations transmitted into the sea-bed pilings affect marine life in some catastrophic way (think whales, or dolphins beaching) and you'll find yourself scrambling to save a billion dollar investment. Maybe an occasional electrical fault that causes all marine life within a click to do that upside-down belly float thing...
No WT is 100% eff of the wind through it because as you say, no wind would be behind it would stop the wind in front, through it. At most about 59% is the most of the winds power you can extract but even that is never even close to what you can get in real life.
The best get about 45% for large 3blade units. But as they say the wind is free. They also say it costs a lot to catch it as we say in sailing ;^P But after payback which is about 2-4 yrs, the energy is almost free for another 50 yrs.
As for your number, 1/ 10,000,000,000,000,000% of the atmosphere's wind power, yes mine is 10,000x's smaller already so it's already less inpact than yours ;^P
As for space most future WT's will be small home, building size taking up no real space more that a couple sq' the point is moot. Same with the Anti solar trolls who say you need to cover whole states to make them work.
A home/building on an 100x100' lot recieves 100k kw/hr solar energy for 5hrs averaged power/day averaged over a yr. Wind can easily be 20kw's 10hrs/day giving 200kwhrs/day.
YMMV but as you can see their is plenty of RE to go around. There is no shortage of energy, just the equipment to catch it. As prices for energy, especially fossil fuels goes up, this energy will be exploited.
Warren, Right wing repubs are not conservatives but regressives fighting change, freedom, rights of everyone who doesn't think like them that has to happen vs Dems are mostly progressives embracing change as an exciting future to have with more knowledge, rights to work with.
Our forefathers like Washington , Jefferson were mostly progressives, tories were the conservatives/regressives trying to control everyone and stop progress. Think about it. Which should you be? The past or future?
Ron Paul is for dog eat dog where the most powerful, ruthless win but make the pie so much smaller because of domination by those who own the marbles they rule little. Of the 3 Paul would end up the facist though Neo-cons a close second. The right has produced little progress but hinders it and freedom instead. Notice repubs for freedom as long as you do it, think their way. I'll stay progressive like George Washington, Franklin.
Fact is no ism is good in itself but best to pick the best parts of each, social to care for those not able and let young talent have the opportunity to excel, progressive to lead to a better future, freedom for all and capitalism reasonably checked to release the creativity, free markets that it brings but without the bubble busts it also brings. Just look at 2008 for why capitalism doesn't work. Without decent regulations it destroys everything in it's path and nearly caused a worldwide depression. If Romney wins they'll cause one because it's the only outcome their policies will bring.
Scott, I agree, the big difference here is the detailed model and its scale, which provides more data. I also think the big deal is the ingenuity of the researchers in deciding what to do with that data in the various scenarios. And I've seen similar claims about solar power that are hard to argue with.
The problems the Colorado River faces are man-made. Manifest Destiny, rapid urban expansion, etc, have endangered multiple rivers in the Western US and around the world.
I think this study shows that if we think sustainably, we can harvest energy from the sun and wind intelligently to meet our needs. Areas of the country are well known for wind-Chicago, Southern California, The Great Plains, for example. Many areas of the country are well known for almost year-round sun-Arizona, Hawaii, Texas, for example.
My cat just ate my post, so I will try to reconstruct it.
In a nutshell, whatever you have in mind, the government will destroy it like they have so many other good ideas.
First, the technology is there are nearly so to put big power stations in the sky to produce the power. I will go along with that. But the financing isn't. The Fed has no money and hasn't for a generation. Their credit is running out, and our great-grandchildren just can't afford any more boondoggles.
Wind power has to be a viable business with minimal regulation and taxation to make it attractive. We all need power, but look at your electric bill and see where your money goes- it ain't all going to the power company. Obama is trying to shut down crucial sections of our power generating sector, coal, for no viable reason other than, "Hey, I'm a socialist! We do these things just because we can." So what is to keep him and the next Dear Leader from shutting this down as soon as a sparrow gets a headache from the turbines? Nothing.
So, if elected Ipromise large-scale wind power cannot succeed in today's fascist government style. We need to keep Washington out of it, and maybe we can stand a chance of using the wind for something other than making promises and getting reelected.
@warren: President Obama is not trying to shut down coal. Record-low natural gas prices are trying to shut down coal. (And they're doing a pretty good job, too).
The Wall Street Journal is not known as a particularly pro-Obama media outlet, but you don't have to take their word for it. Ask the companies that are shutting down their coal-fired generating stations.
"It has nothing to do with environmental policies -- this is an economic decision," an electric utility spokeswoman is quoted as saying in this article.
Warren you obviuosly are biased and lacking in actual facts vs your made up ones.
It;s coal that is so hugely subsidized but now it's being forced to stop killing 30K and hospitalizing 200k/yr in the US alone among it's many other costs in our taxes and healthcare costs to clean up their mess. This comes to about $200B/yr!! Google coal costs and try to learn something.
Obama is for clean coal but big coal doesn't want to change to make that so. Or do you think big corps should be allowed to poison, hurt others so they can't make large amounts of money while forcing the costs onto tax payers? I can think of multiple ways big coal can meet the EPA pollution standards like making syn fuels and using the waste heat to make electricity, etc. This makes little pollution as it's taken out early in the process of gasification plus gives us gasoline, diesel, petrochemical alternatives .
As someone who actually has to make cost effective power sky turbines are a joke with huge practical problems. Though if they can overcome them they get the same help as other RE. But again utility power of any type won't be able to compete with smart home, building systems of many types.
Right now my biggest hurtle to making clean power is repubs, a few coal state dems that are bought and paid for by big energy who in Congress and here in Fla make it illegal to sell electricity. Without that ability it's near impossible to get financing of units. So much for a free market repubs say they are for.
I'm all for getting rid of all energy subsidies as long as the social costs are included in them instead of in my taxes, healthcare, etc costs. Shouldn't big oil, coal pay all their costs? The present corporate welfare system is far more facist than Obama ever has been or will be.
Just look at all the facist money from Koch brothers, etc now going against Obama, others that want big energy to pay their own costs instead of foisting it on taxpayers, keeping the gold and giving Americans the shaft.
First of all, you don't understand Fascism. A private individual can't be a fascist. Only governments can where you just think you own the company but the government really does. That describes America.
Second, those old, tired numbers you throw out about the deaths, etc. is fiction and you know it. Coal is safer than every, you just don't like it.
And don't tell me about Republicans. They are nothing more than Democrats with the ability to fool the public into thinking they are not the Democrats.
Again, big oil has its claws into the political system because it is fascist.
Warren, part of the reason wind didn't take off as expected was mentioned in my article: some previous studies had concluded that the wind farm effects could include environmental problems, some caused by weather changes, in addition to reductions in wind energy caused by turbines "stealing" it from their neighbors
As a footnote to this article, a separate, recent study by the principle researcher, Jacobson, and different colleagues shows that offshore US East Coast winds alone could power that area's entire energy needs for three of the four seasons each year: http://news.stanford.edu/news/2012/september/offshore-wind-energy-091412.html That study can be accessed here: http://www.stanford.edu/group/efmh/jacobson/Articles/I/Offshore/12DvorakEastCoastWindEn.pdf An earlier study by Jacobson et al examining California's offshore wind potential is here: http://www.stanford.edu/group/efmh/jacobson/Articles/I/Offshore/DvorakRenewEn2010.pdf
Wind turbines don't have to capture all of the wind energy, but they do need to grab enough to offer an adequatereturn on investments. No questions about that. But that is no small task, and to keep things running 250 feet up is quite an exoensive task, as well, Using the turbine to drive an air compressor to supply the generator turbine drives would be an interesting way to do it, it would get rid of a whole lot of wires, as well. Of course a lot of energy would be lost as the compressed air cooled, but it is a way to have a very smooth drive. The best part is that it would allow energy storage easily, just by providing tanks to hold the air, But nobody seems to consider it presently.
Thanks for that input, William. Although 100-meter tall turbines were used in the initial simulation, the researchers then recommend turbines 100 feet tall, as the article states. Wind turbines 200-300 feet tall are fairly common right now on some of the larger wind farms.
William, your idea of moving the turbine to ground level and powering, not with compressed air (as you suggested) but with fluid power - hydraulics has been pushed by Eaton Corporation recently.
I like the fact that everyone is finally realizing that economic efficiency drives implementation, not electromechanical efficiency. Wind and sunlight are free. The expense comes in installation, space, maintenance and permits. Like biodiesel, bio ethanol, and other alternative energy, the raw economics are generally unfavorable for the process owner until the government subsidies are distributed. The owners of the incumbent technology can be profitable over a much broader selling price than alternative energy sources as long as utilization is reasonably high. Notice that only the coal mining companies are screaming now? The owners of coal fired plants are happily making cash with the low priced coal.
One main reason for using wind turbines at higher altitudes was discussed in our article on the Altaeros airborne wind turbine, which is aimed at altitudes of 1,000 feet and up:
Winds at those heights, anyway, are 5x stronger so more energy gets harvested; at least that's the theory.
One question is why is it so obvious to me, an electrical engineer, that most of the mechanicals should be at ground level, when the others all want the generators high up in the air? It is fairly simple to go through the numbers and see that high altitiude service calls will cost lots more than those at ground level. Is it really that hard to figure out? I suggested using compressed air because it can be stored until needed, and because an air leak would not cause much pollution. Hydraulics can easily be more efficient, that is true. But hydraulic pressure is harder to store.
Designing a system to be serviceable by robots is not a trivial thing, since they are not nearly as smart as the avaerage human service person. So a system designed to be serviced by robots would cost more because of that. In addition, robots that can climb a tower and service the equipment at the top are not cheap. So from those points it makes more sense to put the minimum of hardware atop the tower.
I read an article about some very high altitude robot wind turbine systems that would be flown up using the generators as motors, until they reached the altitiude where the wind was located. Then they would serve as power generation systems. The problem that they had with these systems is that it is a challenge to deliver multi-megawatts down a cable of reasonable weight. There was quite a description of how to insulate the two or three conductors bringing power down. My suggestion is to separate the conductors, moving them to opposite corners of the airborn structure, since space is a good insulator, and adds very little weight. Such a generation platform could be flown back down to ground level for service, which would remove the expense of climing completely.
UNfortunately it does not appear that this approach has gained favor yet.
It usually costs a lot more to send humans to the top of wind towers, or out in space, or almost anywhere, than it costs to send robots there. Some of the cost is in wages, but there's also safety systems and insurance to protect the humans. In any case, it's usually cheaper to send a machine. The robots described in the story at the link I gave http://www.designnews.com/author.asp?section_id=1386&doc_id=247655 are equipped with test equipment and real-time wireless communication systems, plus vision, so they don't need to be smart. They just need to be a lot like a Mars rover, or a rescue robot, plus climb a tall tower.
Great Post Elizabeth. For me, the most striking take-away is that institutions are looking. Looking at alternate energy sources that just might aid existing energy production and lessen our dependence on fossil fuels. I suspect we will never completely eliminate our need for existing sources of energy. It would be nice to extend their availability and mollify to some degree the expense of finding additional areas to "mine". We all know economics represents a huge factor in the success or failure of alternate sources. Also, the special interest groups factor into most political desicions greatly. I believe a program such as this would have a better chance if we could eliminate politics from the equation. For this reason, I think the study is valuable.
Thanks bobjengr (although I think you meant me, not Elizabeth). I was also glad to see such a thorough, well-designed study done by a reputable institution. I hope that the results are actually used, instead of ignored.
By experimenting with the photovoltaic reaction in solar cells, researchers at MIT have made a breakthrough in energy efficiency that significantly pushes the boundaries of current commercial cells on the market.
In a world that's going green, industrial operations have a problem: Their processes involve materials that are potentially toxic, flammable, corrosive, or reactive. If improperly managed, this can precipitate dangerous health and environmental consequences.
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