I long thought that wind & site studies began with the Danish Wind Atlas (1981). Then, in 2014 or so, I discovered Juul’s papers, and the studies of Ailleret and Serra in France, while researching for a presentation I gave at my workplace. A lot had been published (in books and articles, but also on websites) about the history of wind turbine technology, but as far I could see there was only little historial information on wind & site studies. This is when I started to gather all I could find that was relevant to wind & site works, with the hope to learn more about our predecessors.
After some time, the case of Peter Lissaman was brought to me by a former colleague of mine, who knew already abouts Lissaman’s 1980’s reports on wake measurements at the Mod turbines test sites. These were somewhat known and referred to, also in recent articles, but not in detail. In particular, his seminal theoretical study of wind turbine wakes (1977), often cited, was nowhere to be found. Eventually, we contacted Torgny Faxén who worked with Peter Lissaman; he luckily had a copy of the report, and this was such a terrific moment that I realised I ought to find all the other lost papers from wind & site pionneers (all of them), and look for other gems.
The story on Lissaman, the man itself- and his great contributions, were at least worth a blog post. Therefore, I first set up up Aeolians.net in order to share the good news (we found the report !) and to make the other documents available (I had maybe about 50 of them at the time). Things escalated quickly when I found out, thanks to a wonderful colleague, that I could order books from foreign libraries via my local library here in Denmark. Plus, I have been checking regularly abebooks.com for old conference proceedings, and eventually I could gather this way many more documents. In addition, I received a number of great reports from people I contacted personnally, like Tom Zambrano and Paul Gipe.
Then, I wrote a few more posts, and realised that each of them sparked new questions and led to new research paths. After having gathered a couple of ideas on what could become a introductory paper to Aeolians.net-, its corpus- and problematics, I was lucky enough to find the editors of the Journal of Energy History / Revue de l’Histoire de l’Energie (JEH/RHE). It appeared that such paper was relevant for the “Interpellation” section of the journal, which calls for non-historians to interpellate energy historians on a given topic:
What are you waiting for in order to work on a particular subject, or to explore a particular perspective? This is the question we historians expect from you who are concerned by the history of energy -and by the energy of history. Needless to say, tell us why it would be good to get started, and do not hesitate to indicate the resources available.
I took the opportunity to write a paper, entitled “A call to historicize wind & site studies“, which aims at:
- Explicating the Aeolians.net approach, in order to make it clearer to myself, and to present it formally to the community of wind & site practitioners.
- Drawing the attention of wind- and energy historians to the possible relevance of wind & site studies to the study of wind energy history.
- Explore a few spin-off ideas, namely:
- the link between wind energy meteorology and meteorology, and thereafter the definition and application of engineering knowlegde in relation to scientific knowledge,
- the relevance of wind & site studies for environmental history studies.
I will go quickly through these items in this post, so as to provide a high-level introduction to the paper. Not quite a tl;dr version (which should eventually be posted in Twitter), but instead a light review of the main ideas behind Aeolians.net. I had the pleasure to exchange thoughts about the JHE/RHE article with Matthias Heymann, who works at the University of Aarhus and is a renowned wind energy historian. The JHE/RHE editors were kind enough to publish his review of the article as part of the interpellation; I’m happy to have discussed with Matthias about my approach, and his text provides an overview of the problematics of the article as well. May he be thanked.
, URL : energyhistory.eu/en/node/115.
Aeolians.net, a genealogy of wind & site studies.
I see many interesting aspects to Aeolians.net, and many of these are very personal. I have always enjoyed old libraries and bookshops, collecting old atlases and natural geography books. See below for instance a map of the Gulf Stream system in Elysée Reclus‘ 1873 “The ocean, atmosphere, and life. Being the second series of a descriptive history of the life of the globe“: beautiful, isn’t it ? Therefore, I felt naturally enthusiastic about digging into old papers published in my professional field, wind & site studies.
In the same manner as some craftsmen collect tools and testimonies-, research on past traditions-, and thereby build on the experience of their predecessors, I thought of taking a similar approach, i.e. look for early wind & site works, gather and display them in one place and highlight their respective contexts. Part of being a craftsman is to build on past experience indeed, and I feel that being part of a long(er) tradition is after all very satisying.
Yet, there may be more to this, as I believe that the Aeolians.net library provides, for the study of wind energy history, a complementary perspective to the approach which consists in studying mainly the history of wind turbine design. In the JHE/RHE article, I mention a few examples:
- Wind & site works by the post-war pioneers (Putnam, Golding, Juul, Hütter).
- The NASA wind turbine program, and the 1974 General Electric turbine design optimization study.
- Contributions of wind & site studies to the history of wind energy, and the birth of commercial wind & site services in the late 1970’s.
In a recent series of posts, I went through the wind & site works of some of the post-war pionneers, namely Putnam, Golding, Hütter and Juul. What I tried to show is that they took different wind & site approaches, somewhat influenced by their background and the of wind energy at the time. To put it simply: all were concerned about how much wind energy was available and where to best locate turbines, and did carry out field campaigns and theoretical studies; yet only two had successul prototypes (Hütter and Juul) and only one succeeded in making a turbine robust enough (Juul). From this one could conclude that, sadly, wind & site studies were not that useful (ahem), but when looking in detail: what role did wind & site studies play in these successes and failures ? Were all these wind & site studies designed, executed and used in the same way ? What can they tell us about the different wind turbine design traditions ? Could some important design issues have been overlooked by some but not others ? How has this knowledge been transmitted, who made use of it and in what context ?
The JHE/RHE article highlights for instance that Putnam and his team overestimated the mean wind speed at the test site, which consequently led to overdesigning the generator of the turbine. The article quotes Juul, who retrospectively explains that for this turbine, a smaller rated wind speed would have led to a more efficient design. Thereby, I intend to show that wind & site studies did play a small but significant role in the development of turbine technology. From my perspective, certainly biased by having spent all of my graduate and work experience in Denmark, Juul appears to have coupled successfully wind & site studies and turbine design. His step by step approach, steadily implementing design changes and elaborating prototypes (Vester Egesborg, Bogø, Gedser turbines), was backed up by 1) a sound and pragmatic knowledge of the important aspects of site conditions, which he gathered during his preliminary studies in the early 1950’s, and 2) experimental results where he correlated wind turbine loads and power performance with wind measurements. Again, a small but significant role.
In passing, the article also highlights that in these post-war conference proceedings (OEEC Working Party, the 1961 UN conference), many papers deal with wind & site studies only; that is: without or with only little reference to wind turbine technology. This type of studies is still carried out today, and aim typically at understanding the spatial and temporal variation of the wind resource, either from an engineering or scientific perspective.
Another example which I provide in the interpellation, is the General Electric desktop study which formed the basis of the Mod (or MOD) turbine program in the US. In one of the three volumes of the study (available on Aeolians.net’s library, originaly obtained from the NASA Technical Reports Server), a parametric study is presented. Therein, a turbine type is seemingly optimised with regards to its mean efficienty across a range of wind speed (see details in the article). I have not yet figured out in detail what the optimisation routine was, but looking at the LCoE results it produced, it clearly discarded turbines of the 250-500 kW size compared with MW-size machines. And as the weight and complexity of the large two bladed downwind machines caused (at least, partially) the failure of the Mod program, it seems interesting to understand what role this optimisation routine as played, and how/if the wind & site experience from Juul was considered. Furthermore, atmospheric turbulence was another contributing factor to the difficulty of designing large, slender two-bladed machines, and again here the experience of Juul and the so-called “Danish concept” proved to be key for designing robust machines. This has already been discussed, in particular by Matthias Heymann in his publications, yet I believe there are wind & site aspects to it that are interesting to focus on.
Lastly, and this point was brought my Matthias Heymann during the review, it may be interesting to look at the role and contribution of wind & site studies to wind energy from the late 70’s onwards. This is when our professional field became, well, professional, with the first large scale commercial studies in California, and the birth of our discipline (including pre- and post construction yield estimates, uncertainty analysis for project financing, wake and flow modelling, derivation of wind indices, etc etc). And there, one could think of studying our profession historically, despite its young age (40 years at max), in a similar manner as others study wind turbine manufacturers for instance – so who’s up for it ? The point of the interpellation is to call for historians to look into our microcosm, and I sincerely hope to catch the attention of at least one of them ^^.
Wind Energy Science.
Wind Energy Science has existed for about 45 years, if one considers that it was born really with the 1973 conference in Washington, and the Mod program. During those early years, the Department of Energy funded a number of theoretical and experimental studies in many R&D labs and research instutions in the US (Aerovironment, Colorado State, Georgia Tech, NASA, Oregon State, Pacific Northwest Lab, SERI, etc), to which many clever and brilliant minds contributed (Wilson, Lissaman, Spera, to name a few). There are today at least two main journals (Wind Energy, and Wind Energy Science) dealing exclusively with Wind Energy, and some leading research centers (DTU Wind Energy, Oldenburg University, CENER, NREL, etc.) have fostered high quality research in the past decades.
But, what is Wind Energy Science exactly ? Of course it is well defined by its leading scholars in their respective text books, but I believe it could be interesting to look across and beside these different research institutions, to understand where it sits, in what context and how it interplays with the other stakeholders (states, developers, grid operators, consultancies, manufacturers, but also other fields of science like Boundary Layer Meteorology or Energy Systems). Some in Wind Energy Science are doing fundamental research in aerodynamics, or atmospheric turbulence, while others are often working on commercial contracts with the industry; how is scientific knowledge produced, dealt with and exchanged in these networks ?
We are often discussing, as practioners, the difference between engineering and scientific knowledge. We often fall into epistemological fallacies (one of the most common one is mistakenly considering some explanation/parametrisation of nature as “true” because it is common practice, or because it works well within a given design framework/standards). Could there be a way to illustrate this interplay between engineering and science by studying Wind Energy Science and its historical developments ? For example, I often take discussions on the validity of the wind- and wave models we use for our studies. Are they right, or wrong, in what way and does it matter ? The famous saying “all models are wrong, some are useful” is only of little help, as it barely scratches the surface of some deep epistemological problems which the atmospheric scientists have been tackling since the beginnings of numerical weather prediction (in the article, I mention the works of Wendy Parker and Martin Mahony for instance). There is a great deal of thinking into defining accurately what we are after, what the models are here for, what they can and cannot, how to validate them using measurements, how to analyse these validation results, how to understand the model results and what recommendations to take. A number of issues can arise from either skipping or passing too quickly through any of these steps, and may result in a common pitfall which is that doing modelling often adds uncertainty to the final result, because it adds more reasons to be confused and not because the uncertainty is indeed present. This is to say that modelling is essential to our work, but that it needs be carried out carefully, and that both modellers and model users need to take part in it; while knowing each others’ goals and ambitions. See the nice discussions and examples on a blog called “The Wind Vane” for more info on this. Having a wider, and historical perspective on these issues would I believe help the practioner.
Wind & Site studies, their wider context.
Lastly, because after all wind & site studies deals with wind and atmospheric conditions in the atmospheric boundary layer where spend the vast majority of our lives, I think there could be links with Environmental History. Now, of course, I am writing this because I have become a fan of this field of humanities, which (Wikipedia) is the “study of human interaction with the natural world over time, emphasising the active role nature plays in influencing human affairs and vice versa“. #EnvHist books titles sound deeply poetic, see for instance “The Little Ice Age: How Climate Made History 1300-1850” or “The Shifting Sands of the North Sea Lowlands: Literary and Historical Imaginaries” and “Fathoming the Ocean. The Discovery and Exploration of the Deep Sea“. The EnvHist community is very active and a number of conferences and events are organised throughout the world, you can find a lot of info on Twitter and on the web, see http://eseh.org/ or https://aseh.net/.
How does EnvHist tie together with Aeolians.net ? Well, first we are here talking about a human activity, engaging many different groups of people, over several decades, trying to understand and quantify a natural phenomena which we are all naturally acquainted with and to which we relate easily, with the purpose of designing machinery and producing power. This is in part, an effort similar to the study and characterisation of seas conditions for ship building and coastal management, yet noticeably more modest. I would like here to refer to this wonderful article called “Domesticating Waves in the Netherlands“, by Stefan Helmreich; how I wish such things could be written, at a more modest level of course, on wind & site studies and the history of wind energy ! From a more scientific perspective, a topic like “Air-Sea Relations Through History” could be well suited for a discussion on the characterisation of offshore wind and wave conditions for the design of marine structures, in relation to common – yet slighlty different – design frameworks and traditions that are oil and gaz and offshore wind. From a historical perspective, it could be interesting to interrogate how sailing and marine traditions in old maritime nations like the UK, Denmark or the Netherlands have fostered the development of the offshore wind industry, for instance. Links could be made to the newer markers (the US, Taiwan, Japan), where projects are being developed today.
More generally, only considering wind & site studies as one of the multiple studies that need be carried out before and after the construction of an offshore wind farm, one could wonder about all of the knowledge which is produced about the local, sometimes very specific (soil, wind climates, currents, fauna and flora), but also generic (wind-wave parametrisation, wind profile and its depedency on stability) natural phenomena at given site: where is this knowledge going, what does it consits of, who uses it, (how) does it contribute to common knowledge of human and natural geography ? In the interpellation, I am giving the example of the Dogger Bank, a now submerged area in the North Sea which was an emerged land during the Mesolithic era (Doggerland). A lot of what we know about Doggerland comes from seismic studies in the North Sea, which were carried out for oil and gaz extraction. Could there be a way, similarly, to draw the contours of offshore wind site condition surveys (soil, wind, waves, mammals, benthic, archeology) and understand if/how they reach domains outside of our industry ?
Conclusions
In this post, I have provided a summary of the main themes covered in the interpellation “A call to historicize wind & site studies“, published in the Journal of History of Energy / Revue de l’Histoire de l’Energie. This introductory paper to Aeolians.net provides (at least I hope it does..) an overview of the relevance of the documents hosted on Aeolians.net’s library for the practioner, but also for the historian (wind energy, technology, or environmental historian).
As I wrote earlier, I have plans for Aeolians.net this year, and welcome contributions. In particular, information and tips about pre-1990 (ca.) wind & site studies from Southern Europe, Oceania , Asia, Africa, and any other region would be wonderful :).
Like always, comments and questions are wel-come.
Rémi
