Renewable

Wind and site studies have not been treated in much detail in historical work about wind energy technology and wind power use. I appreciate the authors’ observations and arguments and the questions he raises. The author is not a historian, but an engineer. We had a useful and productive exchange, after I wrote a review and allowed the editors to reveal my identity. The exchange was productive and very agreeable. Both of us – historian and engineer – learned from it. I thank the author for his openness and interest in historical work. Historians of science and technology have ample and not always fruitful experience with engineers. Some engineers seek to challenge historians’ accounts for their critical narratives and the lack of appropriate detail and appreciation of engineering accomplishments. This exchange was clearly different. The broader message to make is that conversations across disciplinary boundaries are necessary and profitable. Fruitful they can be, if the dialogue is on both sides not understood as an opportunity of teaching (or convincing) the other, but of exploring and learning from each other. Asking questions, like the author has amply done in his article, is not the worst for a start.

As the author is an engineer, it is not surprising, and for the scope of this journal fully acceptable, that he does not provide a full account of the state of wind power historiography. Many historical publications on the history of wind power have become available in recent years; and many of the examples the author mentions have been covered to some extent in this literature.1 Still, the author has a valuable point to make. His emphasis on wind and site studies is a valid argument. This domain had skipped my and other historians’ attention for at least two reasons.

First, historical actors partly neglected wind and site studies in their investigations, or did not pay much attention to it. During the 19^th century, for example, American turbines emerged in the American Midwest, because farmers needed power for pumping water. Their design originated from practical experimentation rather than any engagement in wind and site studies. In the early 20^th century, Saxony (a hilly region in central East Germany) became a center for the production of American turbines in Europe, most of which were exported to other places. Saxony, however, was a place not known for windy coasts (which are several hundred kilometers away), but for a productive and innovative metal industry adopting this technology. Wind and site studies were not an issue for this industry. In the 1930s, a controversial pioneer such as German engineer Hermann Honnef planned to construct huge towers for wind power use in the middle of large cities. In this case, solid wind and site studies also lacked. Siting followed political interests rather than scientific results or technical reasons.

Second, partly, on the other hand, wind and site studies and their roles are only little visible in the historical sources, even though pioneers such as Johannes Juul and Ulrich Hütter paid attention to it. The author shows that a range of wind power pioneers in the 20^th century indeed engaged in wind and site studies. Most importantly, however, the author clarifies the significant role of wind and site studies not only for optimizing energy production through appropriate siting but for optimizing turbine design. Turbine design, a delicate and demanding engineering task, has caught a lot of attention in historical accounts with focus on different design approaches, learning experiences, etc. Wind and site studies, however, remained neglected as an important piece in the puzzle of building reliable turbines. Turbine structure and generator dimensions requires wind and site studies. Wind conditions also cause atmospheric turbulence, which defines fatigue loads at the blade roots and needs to be accounted for appropriately. The case of Putnam’s experimental turbine in the USA during the 1940s shows the importance of these points.

On the other hand, historical precursors to wind and site studies still appear marginal compared to the explosive expansion of wind technology since the 1970s, in which wind and site studies slowly became a crucial and increasingly professionalized element. Initially, during the 1970s and 80s, wind studies mainly served for pushing the narrative that abundant wind power resources were available and represented a competitive energy source compared to large fossil power plants. It served for siting decisions rather than turbine design. Most governmental wind power programs, launched after the first oil price crisis in 1973, focused on very large wind turbines (hugely transcending power ratings of historical turbines). Not wind and turbine design studies, but the politics of energy pushed the focus on large turbines, notably the competition against much larger conventional power plants. In Germany, it was the government’s decision (not an engineering decision) that the largest experimental turbine in its research program, built in the early 1980s, had to reach a height of 100 m (called GROWIAN project). Wind and site studies, though an emerging discipline, hardly affected the misguided and ill-fated GROWIAN.

Only more recently, wind and site studies have become a crucial element for turbine design and the optimization and prediction of wind power yields. It would be interesting to investigate more in detail how this special domain of wind technology developed and expanded. When did wind turbine builders start to develop in-house expertise in wind and siting? At which point in the history of wind turbine innovation did it receive attention? Who were the drivers of this discipline? What disciplinary background prevailed? The author suggests that wind and site studies have become a specialized discipline pursued and developed within wind turbine companies. How did this development play out for different wind turbine developers? What expertise did wind and siting departments develop? Which trajectories of institutionalization and professionalization did wind and site studies take? Are there significant national differences? These are historical questions about the differentiation of knowledge production in the history of wind technology.

The author raises many further questions. He experiences, it appears, the emergence of wind and site studies as a new research domain also as a challenge. Differentiation constructs boundaries and creates distances. It raises questions of professional identity and about the relation to other knowledge domains. Is he a meteorologist or an engineer (or both)? Is the knowledge he and his colleagues produce relatable, even usable in other domains? Historical research can help to find answers and deepen the understanding of this knowledge domain. Engineers, like the author, who sense these open questions and seek broader understanding, help historians, on the other hand, to ask new questions and develop new historical narratives.

• 1. A first wave of major publications comes from the 1990s: Karnøe 1991; Heymann 2018 (1995); Gipe 1995; Righter 1996; Heymann 1996; Heymann 1998; Verbong 1998. A second wave focusing on various aspects of innovation and policy in recent wind power developments started in the 2000s: e.g. Ibenholt 2002; Kamp 2002; Garud and Karnøe 2003; Neukirch 2010; Nielsen 2010; Nielsen, Heymann 2012; Heymann 2015; Chlebna 2017.