This article is the second one of a series of five posts dealing with wind & site studies carried out by some of the major wind energy post-war pionneers (Putnam in the US, Golding in the UK, Hütter in Germany and Juul in Denmark). The first four articles will provide highlights of their works. It is my impression (I may be wrong), that these studies are not known among the community of wind & site practitioners, and that they deserve more attention.
As you may already know, Aeolians.net does not deal specifically with wind turbine design (the topic is well covered in various books and essays), but instead focuses on historicising wind & site studies. Therefore, these will be at the core of the articles, and some wind turbine design issues will be left aside (external references will be provided for the curious reader).
The aim of these articles is first of all to provide references to the major wind & site works by these pionneers. This is done either by pointing directly to a scanned version of the document in Aeolians.net’s library, or by referring to the book on worldcat.org (unfortunately, for copyright reasons the books of Putnam and Golding are not freely available on the net).
This series of posts also aims at comparing these pioneer’s studies: what questions do they attempt to answer, and by what means ? how are they linked to wind turbine design ? what results have been obtained, and how are these relevant today ? The last article of the series will compile and combine the comments and reflections of the individual posts.
Edward William Golding (1902-1965), unlike Palmer Putnam (1900-1984) and Ulrich Hütter (1910-1990), but like Johannes Juul (1887-1869), left this world without witnessing the revival of Wind Energy in the 1970’s. His contribution to the UK national program carried out by the Electricty Resarch Agency (ERA) was major, and included mostly wind & site studies. His book “The Generation of Electricity by Wind Power” was still quite popular in the 1970’s, for instance some of its wind statistical distributions were used by General Electric in their monster turbine optimisation study in 1976. In this article we will focus on three main topics:
- The search for windy sites, and the study of the flow above hills.
- The study of the “structure” of the wind (what we call nowaday the wind spectrum) and its influence on design and energy production.
Before starting, see below the only photograph of Mr. Golding I could find on the internet. It is taken from an article of the New Scientist from 1957, and is a good introduction to his work (the link to the article is in the caption of the Figure, it you wish to read further). Sadly enough, Mr. Golding does not have his Wikipedia page, this need be fixed (but not now).
For writing this article, I have used the following sources of information. The vast majority of the documents are on Aeolians.net library.
On E.W. Golding:
- “Edward Golding’s Influence on Wind Power” by Price (2005-12-01). |Link|.
By E.W. Golding:
- “Note on the Estimation of the Total Practicable Installed Capacity of Wind Power Plant in any Country“, in “Technical papers presented to the Wind Power Working Party” (1952) by the Committe for Productivity and Applied Research, Working Party no.2 (Wind Power) of the Organisation for European Economic Co-operation. |Link|.
- “The Selection and Characteristics of Wind-Power sites” (1952), in “Reports on Wind Power Published by ERA 1949 to 1968, Volume 1: Wind Measurement and Characteristics” (1975). |Link|.
- “The Generation of Electricity by Wind Power” (1953). |Link|.
- “The economic utilization of wind energy in arid areas“, in “Arid Zone Research – VII. Wind and Solar Energy. Proceedings of the New Dehli Symposium” (1956) by the
United Nations Educational, Scientific and Cultural Organization (UNESCO). |Link|. - “Using the Wind for Power” (1960).
- “Studies of wind behaviour and investigation of suitable sites for wind-driven power plants” in “Proceedings of the United Nations Conference on the New Sources of Energy. Solar Energy, Wind Power and Geothermal Energy. Rome, 21-31 August 1961. Volume 7, Wind Power” by United Nations (1964). |Link|.
Additional work by Energy Research Agency (ERA):
- “Reports on Wind Power Published by ERA 1949 to 1968, Volume 1: Wind Measurement and Characteristics” (1975). |Link|.
- “Reports on Wind Power Published by ERA 1949 to 1968, Volume 3: Design and Testing of Wind Driven Plant” (1975). |Link|.
- “An Orkney Wind Survey” by A.H. Stodhart (1949). |Link|.
Seminal papers by Golding (included in the OEEC report from 1952):
- “Large-scale generation of electricity by wind power – preliminary report” (1949). |Link|.
- “The potentialities of wind power for electricity generation (with special reference to small-scale operation)” (1949). |Link|.
Note that I missing the following document (i should be soon be sent to my local library, I have ordered them):
- “Reports on Wind Power Published by ERA 1949 to 1968, Volume 2: Wind Driven Plant and its Application” (1975). |Link|.
Context
Golding worked with Wind Power at ERA between 1949 and the early 1960’s. In the article I mentioned above, Price provides a list of his publications, see below.
Golding has also helped compiled many of the works published by his international colleagues. Much cooperation work was carried out at the time between European wind engineers, as part of the OEEC’s Working Party 2 (Wind Power). See again below the list provided by Price. A compilation of the OEEC report from 1952 can be found on Aeolians.net library. For the anecdote, it is thanks to this forum that Juul could try out some of the French anemometers, and that Serra could derive the first European Wind Map.
It is worth noting that there is a great deal of papers and studies dealing with wind & site issues in there. We will get back to this in the last post of this series.
The search for windy sites
Inspired by the work of Putnam (1948), Golding did a lot of research for finding ideal wind power sites by focusing on smooth hilltops. As you may already know, these are legion in the UK.
In his 1952 paper “The Selection and Characteristics of Wind-Power Sites”, which he wrote with Arthur Stodhart (who made it to the 1973 workshop organised by Savino in DC), shows a map of all the locations where met masts were installed, see below.
One of them was the famous Costa Hill on the Orkney Islands (no. 2 on the map) were a turbine prototype was installed at a later stage. All these areas look quite remote, and they are indeed. This is because Golding and ERA were primarily interested in rural electrification, and as Stodhart wrote in 1949 (see reference above):
In view of the demand in isolated districts for this type of windmill, the Electrical Research Association has for some time been studying their behaviour under various operating conditions, so that recommendations can be made for the most suitable design and method of use. When electricity supply authorities and Government departments began, some
time ago, to take an interest in wind-power generation on a larger scale, the E.R.A.was therefore asked to assist in determining the practicability of such an undertaking.
A lot of work went into these measurement campaigns, and one may wonder why making such large scale experiment without having a turbine ready. Well, it just wasn’t clear to ERA how much wind there was, how much energy there was in the wind, and what the wind was like so we could build machine that could harness it. It is of course a radically different approach from Juul or Hütter in Denmark, but from a central energy agency perspective it can make some sense. Yet, the turbine was missing, so they went on later and build some (unsuccessful) prototypes.
Golding describes in great details the method that was used for selecting the test sites, starting with selecting smooth hilltops easily accessible, making a rough assessment of the resource based on information from the Met Office (that was stage 1). Then, making a site-specific measurements provided further details on the wind conditions, including directionality, gusts, and vertical wind speed profiles (this was stage 2). See below an example of correlation plots between anemometers at different heights above two Orkney hills:
So, having all of this information, how to estimate the power output of a turbine ? Section 7 of (Golding and Stodhart, 1952) provides some very interesting details. They guessed a Cp curved based on report I have not yet got by hands on: “N.Y.U. Final Report on the Wind Turbine, Office of Production, Research and Development WAR Production Board, PB 25370, Washington, D.C.,January 31, 1946”. See below the Cp and power curves, including some considerations on the effect of turbulence on the power averaging (already back then ^^).
The report concludes by describing the wind measurement setup planned during the testing of the Costa Hill turbine, see below:
Measurement and study of the wind structure
Now, I would like to spend some time describing the measurement setup and the great efforts deployed by ERA for carrying successfully these measurements campaigns.
For instance, before making great advances in Control Engineering, Howard Harry Rosenbrock wrote a paper with J.R. Tagg (both graduate students) called “The Design and Development of Three New Types of Gust Anemometer” (1951). The paper is insanely complicated, but see below the basic principle of the instrument. It was used beside cup anemometers in the field studies. The calibration was not simple, but workeable, see the full paper here.
Classical cup anemometers were also used during the vast measurement campaign mentioned in Golding 1952 paper. J.R. Tagg (I could not find more information about him) wrote a paper in 1957 called “Wind Data Related to the Generation of Electricity by Wind Power”, where he describes the different setups and the ERA home-made instruments. The recorders were of course analogic recorders, and only for gust anemometers was the wind speed “plotted” on a piece of paper, analogously to Brazier’s experiments at the Eiffel tower. For long periods, a more simple system was used, based on the following idea: the cup anemometer drives a tape, and a clock controls a pen which moves up and down and makes a mark on the tape at a given frequency; this way when the cup spins fast the distance between two marks is larger than when the cup spins slowly. Overy hour a photograph of the tape is taken and the data is later on processed by the operators.
Golding provides much more details about the different types of anemometers and loggers used by ERA but also by others in his 1955 book. Unfortunately this is just to much information to share in this article but I recommend you get yourself a copy on abebooks if the topic sounds interesting to you ^^.
Of course, installing met masts on hilltops was not easy. See below, the original program was extended after the first report by Golding an Stodhart in 1952: in 1957 J.R. Tagg in “Wind Data Related to the Generation of Electricity by Wind Power” reports no less than 101 different sites (but not Askervein ^^!).
Soooo, it is time to thanks the locals 🙂
All of this information was used for deriving design criteria for the test turbines. This is discussed (theoretically) for instance in (Tagg, 1957) and Rosenbrock 1955 paper “Vibration and stability problems in large wind turbines having hinged blades” (in Volume 3 of the ERA reports).
I could only find test reports from the Cranfield test site with a 10KW machine (see illustration below), but nothing about the Costa Hill turbine, so far. As you know turbulence is critical to wind turbine rotor design, and it is only in the late 1970’s that nowadays tools and methods were developed, using spectral wind measurements and time-dependent aeroelastic codes. It is unclear to me what component failed at the Costa Hill site, so if you have some info please let me know.
Summary
We have been through some of the publications by Golding and ERA, focusing on their wind & site studies. The greatest work of Golding remains his 1955 book “The generation of electricity by wind power”, but it is interesting to relate his work to the other contributions by other ERA researchers, in particular Stodhart and Rosenbrock.
We have also seen that despite the great amount of experimental and theoretical work on wind conditions, this did not lead to great success in wind turbine design and testing.
At the 1961 UN conference, Golding (59 years old) led the session about site studies. This, and his eminent role in the OEEC Wind Power working group in the early 1950’s, shows that he was the most renowned expert in this field at the time.
The next articles will show some of Hütter and Juul’s publications on the same topics, highlighting the role of wind & site studies for successful (but iterative, as opposed to the work at ERA) wind turbine design.
Thanks for reading, comments/suggestions are welcome.
Rémi.
Updated 2018-11-28 with links to the two 1949 papers.
