Review from ENergy Policy
by John Twidell, AMSET Centre, Bridgford House, Leicestershire, UK
Paul Gipe is a knowledgeable and experienced exponent for the generation of electricity by wind turbines. This long book is his updated personal encyclopaedia. The author is keen to tell us all he knows about the development of the technology and its institutional infrastructure over the last 30 years, complete with many personal reminiscences. He naturally addresses a North American readership, but is careful to include wind power worldwide, especially within Europe. The book will certainly be appreciated as a holiday read by other enthusiasts, potential or experienced, with time to spare. In the style of a junior schoolteacher, he explains the technology and economics gently from first principles, for instance explaining electricity generation Faraday-like from magnets passed across conducting wires. He gives himself time to move steadily from such basics to greater sophistication, but always in colloquial style. This is not a text book and so has public appeal.
The truth is that the story he tells needs to be told. The generation of electricity from wind has moved from its unconventional rebirth in the 1970s, to being a mainstream power industry just 30 years later. From the do-it-yourself fringe then in California and Denmark, to today’s major industry, Paul Gipe has witnessed and scribed the whole story. The first edition spoke to practical enthusiasts, probably living in the US rural counties and needing autonomous power. None of this seems to have been removed, as he now adds the information needed to understand modern grid power, including offshore generation. If you are not an American living in a ranch house far from the electricity grid, then be patient of the opening chapters, because the relevance to utility power generation comes later. Nevertheless, a do-it-yourself philosophy underpins the whole book.
The introduction includes explanations of energy and power, justified by elementary equations for the extraction of power from the wind. Photographs introduce the range of wind machines, from small battery chargers to multimegawatt utility-scale generators. Indeed, the use of photographs and diagrams to illustrate and break up the lengthy text is a key feature of the book. We next consider the application of suitable turbines for boats, homesteads, off-grid village electrification and utility grid power. The implication is that either individuals or cooperatives of individuals are seeking to install the power. Company investment and professional development is not a central subject, despite these now dominating the industry. Therefore, still addressing the individual, the text moves to measuring wind speed and, from this, to the calculation of wind power site potential. Relatively complex ideas, such as wind speed distribution and wind shear, are outlined quantitatively, usually by the use of tables and figures in the text, but also by reference to extensive data within the 42 appendices. By now many terms need to be defined and explained; here the author shows his ability to write in an affable yet comprehensive style that will frighten no one. Indeed, one appendix is a lexicon of some 250 appropriate technical terms in English, Danish, German, Spanish, French and Italian. An even larger 30 page appendix, in English only, is a wind energy glossary of over 1000 terms.
Money matters, so here is a complete chapter on economics and financing. This is predominantly from the viewpoint of a householder or farmer either offsetting other electricity generation or installing a stand-alone system. There are tables for cash flow predications, including loan repayments and maintenance costs. Considerable attention is given to the optimum size and capacity of turbine and how such factors affect the finances. Most surprisingly in this chapter, the sale of electricity to the grid is hardly considered; no doubt this absence reflects the past US scene, but the omission is a major weakness. Likewise the economic and financial role of carbon-offset credits is not considered, despite these becoming crucial for the cost-effectiveness of generation by renewable energy.
Gipe is an excellent publicist for wind power. His presentation of wind power technology is attractive and understandable for the general public. The chapter ‘Evaluating the Technology – What Works and What Doesn’t’ describes vertical and horizontal axis turbines, yaw mechanisms, lift and drag forces, blade aerodynamics, rotor design, generators, fixed and variable rotation speed and mechanical control. There are many excellent illustrative photographs and diagrams, but no equations. The style and content is most suitable, for instance, for decision makers and politicians, although an engineer may be frustrated by the lack of analysis and the, albeit few, technical errors (e.g. wind turbine output is about 1,000 W/m2 of rotor area, not of blade area). Because this new edition adds material to the older edition, some of the descriptions are only of passing interest, e.g. the Magnus effect and the Savonius rotor, so the text is lengthy. It is not obvious what is more important to the author – the past or the present? In this book, we have both, but with bias to the past.
Halfway through the book, we meet the modern scene of larger grid-connected turbines. Now the sale of electricity to the grid becomes important, as do the institutional regulations of governments. The European experience becomes important, with the place of Denmark being fully recognised. For instance the distinctive role of ‘feed laws’ in stimulating efficient machines and long-term investment is explained. There are explanations, but again no equations, of grid connection factors such as power factor and harmonics.
Yet, having introduced the modern scene, the book returns with chapters concerning remote living with off-grid power and water pumping. Here US lifestyles dominate, although the author regularly reprimands this fellow citizens for their lavish use of resources; per capita water use three times more than Europeans and twenty times more than developing countries, per capita electricity use twice that of Europe. Such aspects emphasize the need for holistic analysis, so consideration of electrical loads should be as important as consideration of supply. However, one major aspect of US lifestyle is apparent – the tradition of self-help and individual independence. One feels that a much larger proportion of American readers will be motivated and able to ‘do it themselves’ than would be so in any other country. Thus the chapter on ‘Installation’ and the several detailed appendices concerning worldwide products, sales outlets, personal training, maintenance and safety will be invaluable for personal practitioners, wherever they are. This reviewer’s advance copy of the book was sent on a CD, which either on the screen or as print-outs made it laborious to read; most surprisingly there was no index. Hopefully the final publication will be indexed.
Gipe’s 500 page personal ‘encyclopaedia’ concludes with ethical motivation for the future. Who can disagree with his aspiration ‘we must envision a system that enhances the quality of life for all people, rich and poor alike’? For Gipe, it seems obvious that each individual should have hands-on acquaintance with such a ‘system’, and such experience gives a sense of ownership. As the expansion of wind power meets increasing dissent from non-practitioners who clearly do not understand even its basic principles, the author has a point. For those that wish to follow such advice, this book gives ample sustenance.