Joules, fuels and the microchip

Energy is fundamental to life, as this intriguing book makes clear in a beautifully illustrated overview of just about all the key aspects of energy generation and use. But it is no mere A to Z technical encyclopaedia. Instead it adopts a novel exploratory approach, starting with the thermonuclear processes in the sun, then tracing energy flows through space and through the atmosphere to earth, and finally analysing the interaction of these energy flows and processes with the ecosystem - including us.

This approach provides an interesting way to explore the multiple aspects of energy, including the way in which human beings have used energy as a basis for industrial expansion. Some of it is what you might expect - statistics on basic energy availability. But even these make you realise how paltry human technological efforts have been: global fossil fuel production is about 300 exajoules, but that is dwarfed by global net photosynthesis at 2,000 exajoules, and the incoming solar radiation at 5,500,000 exajoules.

Statistics aside, the book takes us through basic earth science and ecology to set the stage for a survey of human activities, with energy being the constant link. So we look at how much energy human beings need from food to survive and then at how they have devised machines, including transport and communication systems, to use energy to allow them to do more than just survive.

The historical details, of dietary traditions as well as mechanical inventions, are fascinating, and are woven together reasonably successfully to keep the story of energy moving forward, right up, through the atom bomb, to our latest invention: the microchip.

Strange, then, that what you might think of as the final punch line is missing. The history of energy generation runs up to nuclear power and then peters out. The point is made that nuclear power is on the decline, and still does not produce as much energy as is obtained in the developing world from dung, fuel wood and crop residues. But, apart from brief historical accounts of wind and water power, there is scant mention of the energy technologies taking over - those based on natural renewable sources.

The statistics are clearly stated: the earth intercepts about 170,000 terawatts of power on a continuous basis, whereas at present we generate only about ten terawatts of power from fossil-fuel combustion, with the latter being increasingly problematic in environmental terms. But the logical conclusion is not drawn - that we could harvest at least some of the natural energy flows in the winds, waves, tides and so on. More to the point, there is no mention of the fact that we are already doing this. For example, there is about ten gigawatts of wind-turbine generating capacity in place, and photovoltaic solar energy looks like it could be an even larger energy source in the decades ahead.

You would think that this book could have ended very neatly, in terms of both thermodynamics and history, by exploring the use of these natural sources, instead of ending on the wonders of the microchip. The new communications technologies and computers are obviously important, but equally, the way in which we develop and use the new energy technologies is likely to have just as much impact on the way we live and work It may be that the explanation for this choice of conclusion is the apparent lack of concern in the text over the environmental impacts of energy generation and use. The greenhouse "global warming" issue is hardly mentioned, whereas you might expect a book like this, which looks in some detail at climate science, to explore the issue of climate change in depth. Instead, we are left with a clear and fascinating picture of how "energy" and "humanity" have interacted in the past, but little guidance as to how we might learn from our history.

This is a pity, since the lessons seem clear from the book itself. Humanity has always had to struggle to cope with the vagaries of nature - for example, with the effects of the fierce uncontrolled natural energy flows in the weather system. By burning fossil fuels we sought to remove ourselves from some of these problems. But this, in the end, has only made matters worse. Now we have to come to terms with nature directly - by learning (again) how to use natural energy flows.

This book is clearly meant for students of energy, whether they be independent learners or on environmental science or energy courses. But the omission of a full analysis of environmental problems, and the lack of a forward-looking conclusion, together with the rather poor index, will make it hard for it to be taken as seriously as perhaps it should be.

David Elliott is director, Energy and EnvironmentResearch Unit, Open University.