This article is a translation of Massimo Ippolito’s response to a paper published by the Max Planck institute regarding the potential of high altitude winds.
The Max Planck is scared to fly
Tullio De Mauro informs us, from the pages of the “Corriere Della Sera” that 71 percent of the Italian population is below the minimum level required for comprehensively reading a text of medium difficulty[Italian]. From this, unfortunately, we can deduce that the recent study of the Max Planck Institute can be understood, critically evaluated and read between the lines by a homoeopathic percentage of average citizens. Therefore I apologize in advance for my frankness, accompanied by some discomfort that I am obliged to use. As we shall see we are indeed facing a very contestable work, and frankly, what is even more surprising is the willingness to publish it by the Earth System Dynamics and that to forward it by Quale Energia (which has also kindly offered a right of reply).
Those who are used to read scientific publications will definitely be surprised by the very title of the paper, “Jet stream wind power as a renewable energy resource: little power, Big Impacts” that introduces the spirit of the paper, inexplicably aggressive. In the paper itself, each paragraph devoted too much space, without supporting reasoning, at repeating what has been expressed in the title and then reiterated in the conclusions.
From the works of the IPCC, for example, we are all used all to see every prediction made from a model accompanied by a certain degree of uncertainty. However, it is already difficult to establish a good level of scientific seriousness from one particular statement, contained in the papers of the Max Planck, which states that one can extract from the atmosphere exactly 7.5 TW,1 without providing the reader with appropriate error bars, bars that could be available by running the model modifying their assumptions in their area of plausibility.
They estimate only 7.5 TW, but in hindsight, it is still not that little!
Paradoxically, the study by researchers of the Max Planck Institute, while performed by using arguments that we will prove incorrect, it positions itself among hundreds of other wind resource assessments, as the least generous of all. Even if harsh about it, it is basically another confirmation of the validity of KiteGen and high-altitude wind power more widely. This because it confirms that only by the use of high-altitude wind power it can be possible to extract, in a sustainable way, amounts of energy greater than the world’s primary energy needs despite saying it in direct polemic with a more optimistic study by Ken Caldeira and Christina Archer, in which the available power is estimated at 100 times more.2
In fact, quoting from their publication: “Our estimate for maximum extraction of kinetic energy from Sustainable jet stream is 7.5 TW“3. However, despite this pessimistic limit of 7.5 Terawatt, the noble and precious electricity, is far more than that required by the entire basic human needs! Such requirement today stands at 16 TW fossil, therefore thermal, where much less than half of it is transformed into useful energy services. A coal power plant consumes about three times more thermal energy than its electricity output, and a car burns and scatters five times the thermal energy of fuel respect to the mechanical energy that actually reaches the wheels. Almost all of our energy use is affected by these unavoidable proportions of waste. Therefore we can say, without fear of contradiction, that the present human needs, in terms of power, is widely under 6TW (multiplied by the 8760 hours, to obtain the energy need on an annual basis), if already set in the elegant electrical or mechanical form rather than thermal.
Power or energy? That is the question
Now we will get into the job.
Those professionally involved in energy discussions share with me the feeling of having to endure the oppressive, continuous and widespread confusion between the different concepts of power and energy. On page 202 of the paper in question, the entire first paragraph repeatedly and ineffably combines the two concepts. Here an example: “If we take the present global energy demand of 17 TW of 2010 (EIA, 2010), then this estimate would imply that 1700 TW of wind power can be sustainably extracted from jet streams. However, this estimate is almost twice the value of the total wind power of 900 TW (Lorenz, 1955; Li et al. 2007; Kleidon et al. 2003; Kleidon, 2010) that is associated with all winds within the global atmosphere.”4
The current demand for energy, according to the authors, 17TW, is a Power measure, which is clear (but only to professionals) for whom is willing to understand the average power absorbed by the all services during a planetary year. Yet, this is expressed with a superficiality which is not eligible even for an high school student during an oral exam, let alone a team of researchers, who have also had the opportunity to proofread the work several times before releasing it. Furthermore, stating that the total power of the wind is 900 TW means forcing a physical concept: there is no power in a fluid, if anything, it has energy. At the extreme, you could try to evaluate the energy possessed by the steady atmospheric regime, but that is measured in TWh (terawatt-hours). Those 900 TW, could be the power that the sun transfers to the atmosphere and that is then transformed into kinetic form, or the power that the atmosphere loses into heat by continually interacting with the ground and in the phenomena of friction between the various layers. This should be enough to reconsider that there are many approaches of better quality and certainly of better interest on the theme, like the followings:
Brunt (1939) calculates the total kinetic energy of the atmosphere in 100PWh.
POWER DISSIPATED IN THE ATMOSPHERE
Gustavson (1979) estimated the average total dissipation in 3600TW, (further supporting the data from Brunt)
Gustavson (1979) 1200TW dissipation within the boundary layer with the orography of the territory and the energy transfer to the seas,
Lorenz (1967) 1270TW, Skinner (1986) 350TW, Peixoto and Oort (1992) 768TW, Sorensen (1979 and 2004) 1200TW, Keith et al.(2004) 522TW, Lu et al. at., (2009) 340TW, Wang and Prinn (2010) 860TW.
The differences between the results described above are motivated by analysis that are partitioned and on ordered flows, purely horizontal and potentially exploitable, but basically all the authors are in relative agreement on the orders of magnitude.
EXPLOITATION OF THE RESOURCE
Gustavson (1979) believes that 130 TW can be exploited – 10% of what is dissipated naturally – with an explicit attention to the climate by the author, which in my opinion remains the most credible person who has understood and said everything that there was to understand and say. Another great work is Sorensen’s, which overlaps almost perfectly with that of Gustavson.
Going back to the confusion between power and energy on the paper by L.M. Miller, F. Gans and A. Kleidon, the reader has to be very lenient and approximate to accept these formulations:
“Archer and Caldeira (2009) estimated the potential of jet stream wind power as “… roughly100 times the global energy demand.” If we take the present global energy demand of 17TW of 2010 (EIA, 2010), then this estimate would imply that 1700TW of wind power can be sustainably extracted from jet streams. However, this estimate is almost twice the value of the total wind power of 900TW (Lorenz, 1955; Li et al. 2007; Kleidon et al. 2003; Kleidon, 2010) that is associated with all the winds within the global atmosphere.
Here we resolve this contradiction between the energy that can maximally extracted from the jet stream […], in terms of differences in velocity and dissipation rates, the limit on how much kinetic energy can maximally be extracted, […], atmospheric energetics. The contradiction originates from the erroneous assumption that the high wind speeds of the jet streams result from a strong power source. It is well known in meteorology that jet streams reflect quasi-geostrophic flow, that is, the high wind speeds result from the near absence of friction and not from a strong power source.“ 5
1) There is an artificious accusation towards Archer and Caldeira to say that 1700 TW are sustainable, while the real meaning of their statement was that by having a potential of 100 times the global demand, the extraction is particularly abundant also from a single geolocation, and that for now, we can let go undisturbed what we do not collect. In addition, the estimate of Archer and Caldeira does not only refer to the jet streams.
2) A certain TOTAL WIND POWER is mentioned, associated with all the winds of the atmosphere, and it does not give an average power, or at least mediated by TW per year, which is a serious error.
3) It indicates a maximum energy that can be extracted, which has no meaning except with through a shifted interpretation of energy, being it power.
4) It indicates the maximum kinetic energy that can be extracted, which would have meaning only if there would have been added, even just lexically, a time base.
5) Moreover, the absence of friction is false. In fact we know that in the atmosphere are lost globally 7W per square meter, of which 2.5 W m is the portion eventually available for the wind technologies (not to be confused with the average 700W per square meter, available locally, as the summation of collection in the large cardioids upwind the generators).
The intent of the authors, that forcibly put together different concepts, even at the risk of seeming superficial, it is unclear, and certainly not very scientific. Thinking carefully about it, it all give credits to the suspicion of wanting to attack at all costs the concept of high-altitude wind.
However, in reality no one with a glimpse of wisdom has ever thought to exploit directly the Jet Stream
The Jet Stream feeds disproportionate images and dreams. For this reason, often, when it comes to wind energy, there is a sort of intellectual itch to dissertate on the subject.
Indeed, the wind speed at that altitude is 90 knots average, an equivalent of about 16 kW per square meter, with frequent peaks of over 100 kW per square meter. A single hypothetical fan of only 20 cm in diameter, immersed in the jet stream, could actually provide plenty of energy for a house all year round, both day and night.
However, a machine that is submerged in the middle of the Jet Stream, at 9000 meters above sea level, is difficult even to imagine. Only technologically immature fantasies can speculate as to whether or not is possible to exploit that mighty and unmanageable stream. The high altitudes technologies, in all of its forms, are focusing to the residual flow, which propagates from the jet stream and drops to lower altitudes. Flow that is destined to dissipate its energy into heat while breaking between the tops of mountains, forests and the orography of the area. Do we have to think that the drafters of the paper in question did not know this? That they criticised a technology while ignoring even the simple basics of it? Personally, this is at the same time a legitimate and very disturbing doubt.
And again, the work of Christina Archer and Ken Caldeira, which is cited in the study as supporting the hypothesis, does not focus at all on the possibility of exploitation of the jet stream. The atlas of high-altitude winds that they published takes into account all the latitudes and longitudes at various heights, is therefore unacceptable to attribute their focus exclusively on the jet stream.
The magic inherent in the machines that aim at exploiting the tropospheric wind is precisely the possibility of adjusting the working height in order to find always a breeze, not too strong nor too weak, with the primary goal of competing with the stability and constancy of the thermal power plants, which convert the energy providentially stored by our planet in fossil sources for millions of years.
The high-altitude wind power has also the advantage of finding this energy concentrated in the stationary atmospheric regime, which can be accessed from virtually any place on Earth’s surface, without the need to deploy hundreds of thousands of installations in the territories. What is good about having this huge source of energy accumulated in the jet stream, it cannot certainly be the immature and pointless intention of extracting thousands of TW; but it is instead the awareness that we can seize the advantages of a machine that can draw from the energy losses of this tank to satisfy the operating specifications of a technology and its relative power output.
The Betz limit
On page 206 the Betz law and its limit of 59.3% in mentioned. The mathematical formulations of Betz actually describe the methodology needed to curb the flow of the wind in order to extract energy. They allow us to understand that the wind flow does not have to be fully exploited because it has to flow through the machine without losing all its speed and the energy possessed. A necessary condition to obtain the best result.
However, the Betz’s laws are valuable for wind turbines, which exploit a relatively small wind front limited by the size of the rotating blades, so the wind keeps the residual energy that is not converted by the machine. In the case of high altitude technologies (ground generator), those laws lose much of their importance as the wind front exploitable is dozens of times more than that of wind turbine blades and that the wind speed is reduced only slightly.
The authors of the paper forced the so-called Betz’s law, with the intent to assert that the discovered maximum kinetic power of 7.5 TW is, due to the Betz’s law (59.3%), reduced in 4.5 TW of electric power. This is not true, because if the kinetic power would actually be limited to 7.5 TW, the machines should process wind for 12 TW preserving a flow of 4.5 TW, this absolving the specific that only 7.5 TW Kinetic are subtracted.
It is often said that science and scientists are divided in deciphering various topics, such as it happens for models that describe the climate chaos and its anthropogenic responsibility.
Many politicians do not want to hear about models anymore, probably because they have seen demonstrations of opposing views supported by their relative opposing models. Well, it is a real shame because the essence of a statesmen ad policymakers should be to predict the future with sufficient time to react properly.
I think I have focused quite clearly on the main factor common to cognitive and communication failures on many subjects of a certain complexity. These are about different perceptions and interpretations regarding both dynamic and retroactive phenomena. I can even say that there is a clear line of demarcation between those who study, perceives and is conscious of the various phenomena with their set of dynamic and retroactivities, and who perceives the science and its phenomena with static representations or simple trend projections, as it happens with the mainstream economists or demographers. Unfortunately, it is possible to manufacture the so-called “predictive models” with both mentalities, but with very different qualitative results.
The work of L. M. Miller, F. Gans and A. Kleidon reveals little knowledge of systems’ dynamics. In fact, while claiming to have used a mathematical finite element model, they have applied forcibly and everywhere a series of fluidic brakes as emulation of high-altitude wind machines. A colossal mistake, taking into account that the wind machines must necessarily have a geolocation, and also this aspect has been completely ignored by them.
If the powerful streams of high-altitude winds are so mobile and in near absence of friction, any eventual obstacle would be largely bypassed, creating unprecedented dynamic scenarios, but still possible to model with more rigorous approaches.
Here I reproduce an image to show that, while writing, above England, France, Italy and Greece, there was a wind of roughly 200 kph. As you can see these flows accelerate, slow down and change direction, involving huge masses of air at great speeds and great accelerations. Situation that in a few hours have completely different configurations and a large exchange and dissipation of energy.
It is enough to think about the energy conveyed by the winds as the foehn, frequent in Piedmont, which while it spreads billions of tons of snow on the Alps, is able to raise the temperature of an entire region to summer levels in midwinter.
To give a quantitative indication resulting from the image, above Italy there was a wind power of 200 TW, approximately 15 times the global primary demand. I this case I can properly speak of ‘power’ because I have defined an area (the wind front on the Italian peninsula) and a reference time (the time to which the image refers). The study of these atmospheric dynamics symbolically recreates the difficulties cited above. Yet there are those who think they can put down a handful of equations, in direct conflict with the model, and expects to obtain meaningful results.
Anyway, assuming a limit of exploitation of a few TW represents now a more than comfortable, wide and I would say shareable objective, until we can confirm with more rigorous models, that the more we use tropospheric winds the more tropospheric wind will be available. Basically, maybe, it is a resource that regenerates and grows automatically.
The absorption of kinetic energy by wind turbines, in fact, lowers the temperature of up to several hundredths of a degree in the cardioid downwind of the atmosphere. And the thermal differential, together with the vapour content, is the great engine of the winds.
Most of the exploitation of the resource, for geographical and demographic reasons, will focus on the Ferrel cells of atmospheric circulation, which represent a colossal energy short circuit between the Hadley cells and the Polar cells. Subtract energy to these cells can mean that the surrounding dynamics of the atmospheric circulation will come back in full.
Where are the institutions?
After this essential critical work of the Max Planck Institute, finally we can share the elements to state that, without sounding exaggerated, only from Italy, with its transversal position to the large pseudo-geostrophic flows, we could easily extract 1 TW of power continuously, or more than 8000 TWh of electricity annually. Which, prosaically turned into money, they would amount to a net production of purely endogenous wealth estimated at 800 billion euro each year….!!! Amounts enough to embarrass all the unfair financial manoeuvres that we are imposed to by our governments.
A few dozen of large wind machines or KiteGen farms, distributed from North to South, they would do all work without worries of intermittency, at perhaps not even a tenth of the cost that we would have had from nuclear power.
The fact of writing and demonstrating credible technological design procedures has given us the promise (but only that one) of public funds for a total of 78 million euro. We participated in calls for research and innovation, and the relative commissions have always been enthusiastic about the project, so much that many technical and strategic observers have felt compelled to personally congratulate with me. I remember Zorzoli, Clini, Silvestrini, Degli Espinosa, Pistorio… Then, regularly, the funds were frozen and the leaders sacked, or the procedures went in the hands of lunar bureaucrats. Degli Espinosa and in particular Pistorio at the time of “Industria2015″ had convinced themselves wisely, that at least one KiteGen, produced on an industrial scale, was absolutely a “must see”.
Consuming copious amounts of energy from renewable sources is the credible and unique primary motor for the economy of the future, but it seems that a feeling of powerlessness and nihilism are reigning and that who could give us a hand prefers to see the collapse that we are facing.
1L. M. Miller, F. Gans and A. Kleido. “Jet stream wind power as a renewable energy resource: little power, big impacts”, Earth System Dynamic, 2011, 2, 201-212. p.206.
http://www.earth-syst-dynam.net/2/201/2011/esd-2-201-2011.pdf accessed on the 17th of January 2012
2Pdf available at www.mdpi.com/1996-1073/2/2/307
3Miller et all. “Jet stream wind power as a renewable energy resource: little power, big impacts” p. 211.
4 Miller et all. Jet stream wind power as a renewable energy resource: little power, big impacts”. p. 202
5 Miller et all. Jet stream wind power as a renewable energy resource: little power, big impacts”. p.201-202