Power and its duties

As more reports are delivered by the working groups of the Intergovernmental Panel on Climate Change, uncertainties in the predictions of global temperature and sea level changes are reduced but those of the potential impacts on society remain. In these circumstances, the temptation to wait for more definitive predictions of what will happen is, politically, almost irresistible. Those who urge that precautionary actions should be taken now, need to be able to answer two questions, about the technical possibilities for minimising fossil fuel use and the cost of such changes.

The first of these three books deals with some of the issues in the econometric modelling of carbon taxes and similar instruments. The book derives from a workshop held in Cambridge in 1992, which was concerned mainly with the price elasticity of energy. The early chapters of the book give detailed descriptions of studies of price/demand and elasticities in the United Kingdom and numerous other countries. Most elasticities are derived from the abrupt changes in price in the 1970s that resulted in large capital outflows from oil users to oil producers. But there is no reason to believe that the same impact would follow a gradual and predictable increase in energy taxes with these taxes being recycled back into the economy.

The chapters on macroeconomic modelling are particularly important and informative. Those studies that predict large costs to an economy from energy taxes usually start with the assumption of perfect markets in equilibrium, so that by definition any change incurs costs. These studies also often neglect to recycle the energy taxes. In real economies raising taxes on energy and reducing other taxes can have significant macroeconomic benefits, allowing higher growth with lower energy use. It seems that energy use can be reduced by 20 per cent or more with economic benefits rather than costs. This is confirmed in "bottom-up" studies which often find that the first 20-30 per cent of energy savings have negative costs, at least on a life- cycle basis.

Although many of the chapters in the book originated in the 1992 Cambridge workshop, the editors have ensured that the papers were updated to 1995, and have invited additional contributions from leading figures in the energy tax debate. A wise contribution from Michael Grubb, for instance, points out that energy elasticities are asymmetrical, in that the demand reduction following a price rise is larger than the increase in demand which would follow from a subsequent reduction in price. This is explored in more detail in an earlier chapter which reports on the Department of Trade and Industry energy model, which traces the change in characteristics of the stock of energy-related equipment (domestic appliances in this case) with changing energy prices. An increase in energy prices will provide an additional drive, over and above normal commercial pressures, to the development of more efficient appliances, and this increased energy efficiency will remain even if the energy price falls.

I would strongly recommend this book to anyone who wishes to contribute to a rational debate on the issue of energy taxes. At the present time, the winners in the political debate have been the large pressure groups protecting their own interests, but a patient and continuing rational debate must (or at least should) lead to more sensible policies. When Europe needs to reduce the quantity of resources used in maintaining our quality of life and to increase the number of jobs, it really makes no sense to tax the labour component but not the resource component of production.

The debate on the technical options for a non-fossil future often polarises between those promoting nuclear power stations and those supporting renewable energy technologies. A nuclear power station supplies only electricity, about a fifth of total energy demand even in the most advanced economies. The nuclear accidents at Windscale and Chernobyl, and the continuing uncertainty about the storage of radioactive waste raise serious doubts in most people's minds as to the wisdom of this option. There is, however, one nuclear reactor which is safe (for a few billion years), is Not In My Back Yard (it is 150 million km away) and can supply all of the energy of all types which society could need for the foreseeable future.

The two publications from the Open University provide guides to the technology, resources and applications of all of the renewable energy technologies. The resource pack for tertiary education is indeed a resource which no institution teaching in this field can afford to be without. The pack provides a set of disks with weather, wind, tidal and wave data, an introductory 30-minute video and a comprehensive slide pack covering both the technologies and the applications. The text with the pack includes chapters on costing and resource estimation, solar thermal, photovoltaics, biomass, hydro, tidal, wind, wave and geothermal technologies and a chapter on the integration of renewable sources into energy supply systems, as well as sets of exercises. The pack was originally developed under contract to the DTI, beginning in 1991 , and now forms the basis of OU Course T521.

As one would expect from the OU, the teaching material is beautifully produced, carefully and lucidly explained, and fully accessible to anyone with a general interest in science and technology. An overview chapter discusses world energy supply and demand and places renewables in context. The next chapter gives an excellent introduction to energy costing, both the direct costs and external costs and to resource/cost estimation. Not only are the techniques clearly explained, but the conceptual difficulties of comparing costs for different technologies are very well brought out.

The chapters on the renewable technologies include an outline of the science and technology and applications and also discussions of UK resources, the economics and the environmental impact of production and use. The mixture of technology and economics provides a very good base for considering the potential value of each source, though the text does occasionally show its age in the more rapidly changing fields. The chapter on photovoltaics, for instance, has student exercises on estimating the land area required for a central power plant in the UK, while no one now would think of using multi-kilowatt PV systems anywhere other than in building integrated arrays, which are barely mentioned.

The resource pack has a separate folder containing booklets on commercial products and reprints of papers on the various aspects of renewables. The idea is excellent, but the execution leaves much to be desired. The product literature is all 1993 vintage, and can thus give a misleading impression on the commercial state of the art. The reprints are a puzzle. One might expect a selection of classic papers, but, for this reviewer at least, it seemed to be a collection of what the authors had to hand at the time. The most serious blunder is the inclusion of a reprint on the environmental costs of energy which is so far from the international consensus as to be quite misleading for teaching staff and students.

The book on renewable energy is for the OU T265 course. It is clearly derived from the material used in the resource pack, discussed above, but updated and expanded. It is again a pleasure to read, beautifully produced, with excellent photographs, superb graphics and clear, lucid and careful explanations in the text. The content and coverage are very similar to the text in the resource pack, but in a much less wrist breaking form. This is an outstanding undergraduate level textbook which deserves to become the standard text. I can only urge all those who are teaching courses in the field and all students, formal or otherwise, to read and treasure this book.

Robert Hill is director, Newcastle PV Applications Centre, University of Northumbria.