Nolan Clark, an early wind pioneer, summarizes a lifetime of developing and testing wind turbines for agricultural use in Small Wind: Planning and Building Successful Installations.
Despite the title, Clark wisely includes larger, or what he calls mid-size turbines, as they too can be used in distributed applications. The terminology remains in a state of flux. As turbines and wind power plants have grown ever larger, there arises a need for new terms to describe the myriad ways wind turbines can be used, both large and small. That term is distributed wind. Clark devotes a whole chapter to this topic.
People who have followed my writing over the years will see familiar terms in Clark’s book because many of the terms I use are derived from those used by Clark and Vaughn Nelson three decades ago. For example, systems used off-the-grid are referred to as “stand-alone applications,” because that’s just what they do, they stand alone, using batteries.
Clark is an old wind hand and this is revealed in typical understatement when he explains how Stearns brakes on the high-speed shaft of early induction machines were used. These brakes were used to stop the turbines during normal operation and were notorious during emergencies. Clark simply advises that such brakes should only be used to park the rotor after it has come to nearly a stop. When used as primary brakes, “Many gearbox failures have left these brakes useless.” That’s the voice of painful experience talking and many American manufacturers of the 1980s would have been wise to seek Clark’s counsel.
Clark’s Midwestern values come through in this slim text. For example, when writing about zoning regulations under a section on “Abandonment”, he clearly states that zoning authorities should have a policy in replace that demands repair of inoperative wind turbines or their removal. For those of us who grew up in the Midwest, this just makes sense. If you don’t use, take it down. However, after more than three decades in the wind business I can say that Clark’s simple proscription is not universally accepted. These principles reveal why I’ve followed and used Clark’s work over so many years. You won’t find mention of the moral obligation to remove inoperative wind turbines in any other book on wind energy.
Clark’s book will make Mick Sagrillo happy. On page 86 is a photo from the Des Moines Register that even Sagrillo won’t believe. It’s a photo of a VAWT on the roof of a single-story suburban home—surrounded by trees. Clark admonishes the reader that “Sadly this is more typical than the exception for roof-mounted turbines.”
As one of the early proponents of standards and certification to weed out the hustlers and charlatans in the small wind business, Clark offers a nearly complete certification report for one small wind turbine as an example of what consumers should expect. Certification, many years in the making, and with significant contribution by Clark and his staff at the Agricultural Research Service’s Bushland station, is an achievement Clark can be proud of.
Clark advises that most small turbines in the 1 kW to 2 kW size will be destined for installation off-the-grid. Larger small turbines in the 2 kW to 5 kW size will be interconnected with the grid in residential applications while still larger turbines 10 kW and greater will be used for interconnected applications at farms and ranches. This is as a succinct description of the small wind turbine market as you will find anywhere.
There is also a useful section on water pumping, a subject neglected by nearly all books on wind energy. Clark and his Bushland team probably have done more to further wind-assisted water pumping technology than any other research center in the world. Students of wind technology who are interested in this application will be rewarded by picking up his book for this section alone.
Clark, Nolan. Small Wind: Planning and Building Successful Installations by Nolan Clark. Waltham, Massachusetts: Academic Press, 2014. 224 pages. ISBN-10: 0123859999, ISBN-13: 978-0123859990. 6 inches x 9 inches. $80 cloth, $70 digital. Printed in the USA.
Table of Contents
Chapter 1: Introduction to Small Wind
Chapter 2: Site Evaluation
Chapter 3: Needs Evaluation
Chapter 4: Wind Turbine Components and Descriptions
Chapter 5: Towers and foundations
Chapter 6: Machine Selection
Chapter 7: Economic Considerations
Chapter 8: Permitting
Chapter 9: Installation
Chapter 10: System Operation with Electrical Interconnections
Chapter 11: System Operation in Stand-Alone Machines
Chapter 12: Operational Troubleshooting
Chapter 13: Distributed Wind Systems as a Growth of Small Wind
Chapter 14: Future of Small Wind