Global Warming...New Report...and it ain't happy news

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A wind turbine must be able to withstand the highest winds expected to occur in its planned physical lifetime. It must also be sized so that it can produce its maximum power output at the highest (say) 10 percent of the expected wind velocity distribution in its location. That means inevitably that the average power output of such a device is likely much less than half its design maximum power output.

This is simply a fact that must be dealt with in design. Areas that have higher average wind velocities and narrower distributions of wind velocity are therefore more suitable locations for such turbines. This is not so much an intrinsic defect of wind power, as a design consideration in optimizing it in a given location. The real defect with current wind turbine designs is that they are, on average , a much more expensive source of power than coal or gas fired plants, which themselves are much more expensive sources than nuclear plants.

We can hope for and expect new designs of lighter and more durable wind turbines that can function relaibly for long periods without maintenance. That is what is required to get the cost down to competitive levels. However, it is likely to take some time.

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@georgeob1,

This site says wind farms run about 20 - 40% capacity. Other power plants are typically higher, for example nuclear maybe 60 - 100%, and coal fired plants 70 - 90%.

It is evident that to supply all electrical demand with wind, we would need at least 3 times, probably 4 times or more the amount of electricity needed in terms of rated capacity, plus a massive storage system. Solar would be no good at night, so already the capacity of solar is limited to only half a day, plus factor in cloudy days.

And as has been discussed at length, massive storage systems that would allow solar and wind to exceed more than a minor contribution to the mix, they have not been developed or perfected on a commercial scale so that anyone would invest into these things in the near future. It will take alot more work and time, and meanwhile wind is delegated to being only a minor contributor for electrical generation only.

http://www.ceere.org/rerl/about_wind/RERL_Fact_Sheet_2a_Capacity_Factor.pdf

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@okie,

There are available solutions for the storage of excess electrical energy, however they involve substantial conversion losses. Lake Smith dam in Virginia is an example. The upper and lower lakes are separated by a large dam several hundred feet high. Excess electrical power in the regional grid is used to pump water from the lower to the upper lake at night. When demand is high the water flows back down through a turbine generating needed electrical power.

In today's networks there is generally very little excess power, because about 16% of our generation is (wastefully) done with natural gas fired gas turbine plants which can be started up and shut down virtually by pressing a button. They are routinely started up and shut doen to adjust to the diurnal cycles in demand, while the coal and nuclear plants run at steady levels.

Is is a very simple matter to operate a nuclear plant at a variable output determined by power demand (that is how the reactors in submarines and nuclear carriers routinely work), and with a fair amount of extra cost, coal fired plants could be made to do this as well. They don't do so now simply because they are much more efficient than the gas plants and it pays the utility to run them at full power.

In short, the variability of wind power is itself not a serious defect as long as it is no more than about 20% of the total power generated, because the other sources can have their output levels adjusted to meet the demand. The real issue with wind is its relative cost. The utility must have available reserve generating capacity to meet light wind conditions, just as you note. Given that, it simply makes no sense for them to shut down or reduce the output of a coal or nuclear plant in order to produce power in a wind turbine that costs more than twice as much per unit of output to operate.

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@georgeob1,

Excellent post, George, some good information, so I gave you another thumbs up. Cyclops has hit me every time I assert that no practical mass storage system is available or perfected on a commercial scale. He has pointed out the water pumping systems, and as you point out, it has been used with hydro-electric, but with its inherent problems. Also, water is not so easily available for use, even if it was an efficient or economical system to be considered with a wind farm, which seems to be problematic for several reasons.

I don't think pumping water is going to be the answer to the mass storage. Who knows however, but there are several competing ideas being worked on, but again none offer the magic bullet right now. For the reasons you state, it just doesn't look like wind can get over the 20% range or so, which I am all in favor of by the way, but again it is only a minor and partial solution as it stands now, and will remain so for another decade or two, I think.

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@georgeob1,

George - thanks for me as well - though I don't bother with rating either post or poster - and now another question:

Years ago I walked under the James Bay generators: my hair literally stood on end - there's so much electricity around. Is there any way to improve not only local storage, but also long-range power transmission by using DC instead of AC?

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I was recently by the Bosque del Apache wildlife preserve near Albuquerque and made a mental note to return this fall when the snow geese and sand cranes begin arriving. It is an awesome sight. (Our sand cranes are also being used as surrogate parents for rare whooping cranes in an attempt to save that nearly extinct species.) But then I noted comments from West Texans who are also in the migratory flyways for these magnificent birds and how they no longer come since the wind turbines started going up en masse there. As the plans of T Boone Pickens and others are to place the turbines any place there is space to do so all over West Texas, the concern is that the birds will lose that important migratory route entirely. Fewer birds have also been noted at Cheyenne Bottoms preserve in southwest Kansas. As the turbines become more and more prevalent in New Mexico, will the Bosque del Apache become barren of birds as well?

Pickens and other investors are looking to make major bucks with the wind turbines and the land owners who allow these things on their property are enjoying the royalties paid. But there are consequences too--some erosion of arable lands and aesthetics being probably the most minor. It may be that fears for wild life are mostly unfounded. Somebody (High Seas?) pointed out the discerned human health risks involved with living/working near these things and that could apply to other living things too--we have too little experience to know. There have been intermittant but compelling reports of risks associated with living near or under power lines to both humans and cattle.

I am not opposed to wind generated power at all, but it may be that it is actually of no more advantage to us other than the fact we are in no danger of running out of wind.

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@Foxfyre,

Over the last decade, several surveys in Europe have shown that cranes (and other larger birds) fly round working windturbines in a distance of about 400 to 500 meters.
That's a reason why no windparks get building submissions along the routes of migratory birds.

Not working windturbines are an obstacle for any birds like trees, house, chimney etc.

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@okie,

Quote:

Solar would be no good at night, so already the capacity of solar is limited to only half a day, plus factor in cloudy days.

It's certainly true that cloudy days play a role. However, that can be mitigated by choosing an appropriate location. (Likewise, you wouldn't build a wind farm in an area that has no steady wind most of the year.)

Apart from that, it also depends on what kind of solar power you have in mind. Photovoltaic generates electricity from sun light, and would require to store the electricity. Concentrated Solar Power (CSP) plants, on the other hand, can produce electricity for a long time after the sun has set.

The Andasol power stations in Spain, for example, use a parabolic trough system - which looks something like this:

http://www.reia-nm.org/images/solar/large/parabolic_troughs_2.jpg

The troughs are constructed as parabolic mirrors, with a long tube running along the centre. The mirrors reflect the sunlight and concentrate it on the tube. A fluid runs through the tubes and absorbs the heat from the concentrated sunlight. And after passing through the array, the heat is used to generate steam and power a generator - essentially like in any other conventional power plant.

http://www.solel.com/inner/product/Application%20to%20Power%20Plant1.jpg

However, instead of storing the electricity produced from the generator, it's actually more efficient to store the heat generated by the system during the day.

The Andasol plants use a system of liquid salt heat storage. This stores the heat so effectively, that electricity can be generated even 7 ½ hours after the sun has gone down. (Andasol 1 fact sheet - PDF)

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@old europe,

I like it, oe, good information. I hope this technology keeps advancing.

From a philosophical point of view, the sun is the mother source of virtually all energy here on the planet, even the fossil fuels were generated from the sun over a long period of time. And wind is the result of heat. Ultimately, the answer may lie with the sun and perfecting the technology to tap into it in more directly in more efficient ways.

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@okie,

okie wrote:

Quote:

And wind is the result of heat.

I'd thought that winds are related to pressure?

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@Walter Hinteler,

And I thought the pressure differentials are determined by the temperature differentials.....

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@High Seas,

Hmm.

Proverbs 30:4 "Who ... hath gathered the wind in his fists? ... ... ..."

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@Walter Hinteler,

Hmmmm..... In God we trust, everybody else has to take the exam:

Quote:

The atmospheric gases are concentrated in the lowest layer of atmosphere, the troposphere. 50% of the atmosphere lies below 5.6 km in altitude. 90% of the atmospheric gases rest within 16 km of the Earth’s surface. That is why heat transfer is impeded at higher altitudes, and that is also why the atmospheric pressure decreases as one travels out into space away from the Earth.

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@Foxfyre,

Foxfyre wrote:

As the plans of T Boone Pickens and others are to place the turbines any place there is space to do so all over West Texas, the concern is that the birds will lose that important migratory route entirely. Fewer birds have also been noted at Cheyenne Bottoms preserve in southwest Kansas. As the turbines become more and more prevalent in New Mexico, will the Bosque del Apache become barren of birds as well?

Pickens and other investors are looking to make major bucks with the wind turbines and the land owners who allow these things on their property are enjoying the royalties paid. But there are consequences too--some erosion of arable lands and aesthetics being probably the most minor. It may be that fears for wild life are mostly unfounded. Somebody (High Seas?) pointed out the discerned human health risks involved with living/working near these things and that could apply to other living things too--we have too little experience to know. There have been intermittant but compelling reports of risks associated with living near or under power lines to both humans and cattle.

Overall I don't believe that the environmental or aesthetic side effects of wind farms are any worse than those associated with coal, natural gas, or nuclear plants. All are entirely manageable if we do them wisely.

The real issue is cost. Again, if we have ample sources of cheap energy, we can solve any of the attendant problems. If we don't have cheap energy, we won't be able to do anything. The bucolic and largely imaginary 18th century-like world many environmentalists appear to dream about, was able to support fewer than one billion humans. The real barrier to achieving it is persuading 5 billion people to die.

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@High Seas,

high seas wrote:

Years ago I walked under the James Bay generators: my hair literally stood on end - there's so much electricity around. Is there any way to improve not only local storage, but also long-range power transmission by using DC instead of AC?

Well I think Westinghouse won that one decisively a long time ago. It is true a lot of energy goes into creating the electric field around AC transmission lines. However, as long as there isn't a moving conductor, such as your hair or body, moving through the field, then very little additional energy is lost in the field. I would have to brush up a little on the basics, but I don't think there is any real potential for bettter performance from a high voltage DC transmission system. The ability to readily step up or step down AC power and the efficiency of high tension AC transmission lines is hard to beat. The only cheaper means of transporting energy is in the form of gasoline in a tanker rail car, moving down the track.

Someone mentioned "available" technologies for efficiently storing large quantities of power. I am skeptical: most that I know of involve transformation from electrical power to gravity potential, gas pressure, mechanical energy or some other transformation - and then, of course, back to electrical. The losses attendant to the two process are substantial.

The heat storage system that old europe described for the solar plant in sunny Spain is evidently an efficient way to store the accumulated heat energy directly for a few hours, thus enabling the heat engine that generates the electricity to stay online for several hours after sunset. Clearly a valuable improvement applicable to many solar applications in hot sunny climates. However, it is not a solution for the storage of surplus power on the electrical grid to mitigate diurnal demand cycles, because that too would require two power transformations with the attendant losses. No battery technology exists that could store electrical power in anywhere near the quantities required.

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@georgeob1,

george wrote-

Quote:

The real barrier to achieving it is persuading 5 billion people to die.

They don't need to be persuaded. If average life expectancy is 50 then 100 million will die every year.

The real barrier is persuading them to have fewer children as seems to be happening in Russia and parts of Europe. Whether such reductions in population size represent an evolutionary advantage when cannon fodder are out of date I don't know but if it does then homosexuality, birth control and abortion become respectable and opposition to them becomes subversive.

Recessions and depressions are known to be factors in the birth rate as are other forms of social engineering.

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@spendius,

Well, a modern lifestyle and prosperity appear to be very effective forms of birth control. Even China's population is projected by demographers to peak in around 30 years and start a slow decline. Europe is already in decline and North America, without immigration, would be close to it as well.

All of this, of course, is good reason for us to be optimistic about the works and fate of mankind. I sometimes believe that the environmentalist prophets of doom are closet haters of humanity, who imagine the earth as a benign garden infested by a human virus that should be eliminated.

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@georgeob1,

I've met a few like that George and they are not easy to contradict. Some of those Gnostics, Albigensians and Cathars who eschewed sex had to be smoked out because the powers that were would have had no servants and defenders had they caught on and they weren't for getting involved themselves.

What I can't understand is why a brief glance at the modern young does not put everybody completely off making any more of them. They are a veritable pain in the ass for ever.

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@georgeob1,

Wasn't it Caligula who said--"Oh!! If only the Roman people had but one neck."

What we must look like from the Oval Office and No 10 hardly bears thinking about.

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@spendius,

I wonder what the outcome would be if our nation's children were really educated about the true consequences of the wrong actions their ancestors took, and to think for themselves about how to avoid doing those same wrong things, and how to avoid expecting that doing such previous wrong things again would accomplish different results.

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Global Warming...New Report...and it ain't happy news

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