Edinburgh Napier University

  Although the subject of this book is hydrogen in Thermal Engines, neither the fuel nor the engines are widely commercially available at the time of publication: nor is it likely that this situation will change before the end of this decade. This notwithstanding, the background to this book is with the applications known colloquially as the ‘hard to decarbonise’, by which is meant primarily long-haul transport by land (farther than 500 miles or multi-shift routes), sea and air, and which need shaft power as might be provided by a thermal engine. This introductory chapter is concerned with how quickly, how widely, and at what cost this fuel might be used in these applications in the years up to 2050, and beyond. This chapter starts by tracing, briefly, how there has developed an understanding of the deleterious effects of anthropogenic emissions of carbon dioxide, an important ‘greenhouse gas’ (GHG), on the climate. To reduce these effects, we next trace out how there came to be a level of global agreement that the emissions of these gases should be curtailed, and over what timescale. The GHG are emitted by the consumption of fossil fuels to power a wide range of industrial activities: consequently, there is a myriad of roadmaps and proposals as to how balance economic development with protection of the environment. This involves, at the very least, eliminating the emission of GHG: preferably, by ceasing to burn fossil fuels. For the ‘hard to decarbonise’ application considered in this book, which is predominantly transportation, this implies some fuel other than a hydrocarbon: hydrogen has been proposed as a candidate fuel in some sectors. The suggestion implies the need to evaluate the engineering science and technological aspects of burning hydrogen, which is the concern of the rest of the book. This chapter investigates which applications might use hydrogen, how hydrogen can be manufactured, distributed, and stored at the vast scale required; and at what cost. It does so by reference to, first, global considerations and then, second, considers the recent plans drawn up by two ‘continent sized’ economies. Our epilogue is a cautionary one, reminding the reader of the precipitous rate of development of policy on hydrogen, particularly recently, and implying that developments are likely in future.