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ImageDespite the fact that Richard Baxter has named his book Energy Storage. A Nontechnical Guide, it is still quite a technical book, describing the world of possible energy storage systems. However, it is ‘non-technical’ in that sense that it is written in an easy to read style and therefore readers will not have any problems with following the text of the book and understanding what energy storage is all about.
By Hans Hof, Contributing Editor, Windtech International


The book describes 12 different ways to store energy and focuses on the storage of electrical energy. However, the title promises too much because only electricity storage systems are treated in any detail. For example, the storage of heat energy is not covered.

In the book you will find the systems components of storage systems, the historical origins, the design and operation of storage systems, the cost and benefit issues, and the prospect and challenges of the different storage types. The systems as described vary from pumped-hydroelectric storage systems to compressed air energy storage systems, flow batteries, sodium sulphur, lead-acid and nickel cadmium batteries, flywheels, electrical capacitors and super magnetic energy storage systems. For each technical system the working principles and the applications are given. At the end of the book the relationship between renewable energy and energy storage is discussed. This is the most interesting part of the book because it puts the many advantages of energy storage in the right perspective.

I would like to have seen a chapter about the storage of energy in the form of hydrogen. As experts know, stored hydrogen can be used as an energy carrier to ‘feed’ fuel cells. Especially when the fuel cells are used in combined heat and power mode, the round trip efficiency of the usage of hydrogen can be higher than or at least comparable with the round trip efficiency of polysulphide bromide flow batteries. When I have visited the USA and having analysed the statistics, I have realised that the fuel conservation method ‘combined heat and power’ is not widely used there. That is a pity and a missed chance, I think. So I can understand why Richard Baxter overlooked this possibility. On the other hand, vehicle to grid systems are much discussed in the USA at present and many experts are publishing papers about this. Richard Baxter does not mention this possibility. I wonder why. The storage of energy in the accumulator of electrical cars, plugged into an electric grid during parking, is a huge potential for matching renewable energy production patterns to demand patterns, fulfilling the energy demands of society.

The book is very ‘American’. For international use outside the USA the book is still useful, but be aware that the conditions in other countries could be fundamentally different from the situation in the USA. Richard Baxter uses old-fashioned energy units such as Btu’s (British Thermal Units) in spite of the fact that for decades now the energy world have to use the Joule as the ISO standard energy unit. And to make it even worse he expresses a figure in MMBtu (one million Btu’s). Only American experts are likely to know the meaning of this.

It really is an omission that, in the chapter about thermal storage, the unit in which the costs are expressed is unclear. It says ‘$ per kW shifted’. Since clearly cooling energy is the issue in this chapter, the question remains whether the electrical or the cooling power is meant by ‘shifted kW’. The reference to an article to find that out is not enough; the book should have been self-explanatory on this point.

I attempted to try to find the most cost-effective storage systems by combining bits and pieces of information on the different systems from the book. This gave me a good overview of the book and simulated the way other readers would probably use it. I was pleased that  Richard Baxter follows a very logical and consistent division in each chapter to describe the different aspects of the storage systems, so the reader can easily find the needed information. However, it is a little strange and misleading that in each chapter a single figure is given for the specific investment cost of the storage system described, without indicating the relevant cost ranges. In graph 4-4 on page 171, however, the picture shows that the specific capital costs of each system can range widely.

Regardless of the fact that the coverage of storage systems is not complete, the book gives readers a good insight into the described possibilities. Richard Baxter chose to make it a non-technical guide, and he has been successful in bringing the storage issue onto the table in an easy to read way. All unnecessary details are left out of the book, and therefore its level is somewhere in the middle, between a standard work and a popularised book.

To my mind, one of the most valuable features of the book is that it stresses that storage of energy will become more and more necessary to maximise the benefits of renewable sources such as solar energy and wind energy, which have a hard to predict production profile. Especially for wind, the need to store energy when production and demand do not match this will be very important. This is not only the case for times of overproduction related to the actual demand but also so that the industry can benefit from the higher prices if stored energy from wind power is used when the market price of electricity is high.

By having published this book the Pennwell Corporation has contributed to a situation where nobody can say any more that storing of electrical energy is not possible. My compliments to this corporation and to Richard Baxter!

Energy Storage. A Nontechnical Guide.
by Richard Baxter.
Published in 2006 by the Pennwell Corporation, Oklahoma, USA
ISBN 1-59370-027-X (302 pages)
US$ 69
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