Preface to fifth edition
The market penetration of renewable energy-based systems has accelerated during the years since the Fourth Edition of this book from 2010. Particularly wind power has established itself as a very competitive solution in offshore or resource-favored inland locations, relative to fossil and nuclear energy. The technology showing the most rapid lowering of cost during the period has been solar photovoltaics, that today approach wind in economic viability at sites with favorable solar radiation incidence. These developments are presented in quantitative terms through the revisions of Chapter 1.
The physical basis for renewable energy flows, covered in Chapters 2 and 3, touches upon the climate issue of anthropogenic emissions and other disturbances of the determinants for climates on the Earth. Here the assessments of scientific literature by the Intergovernmental Climate Panel, through its most recent publications, have confirmed the human impacts on climate not only by theoretical models but by indisputable observations regarding world temperatures, ice melting near poles, and increased frequencies of extreme events such as storms and flooding. Details have been added to Chapter 2 and used in an updated discussion if climate change impacts in Chapter 7.
The engineering aspects of renewable energy conversion devices that form the subject of Chapter 4, has been modestly updated by some new scientific ideas coming up during the last couple of years. However, precisely the commercial success of what have now become the “standard” renewable energy technologies is making it difficult for new ideas to become developed from a scientific idea to a commercial product, unless the advantages are so obvious that industry will risk the associated investments. The same might be said for the energy storage technologies that are the subject of Chapter 5, but here, particularly for storage of excess power and regeneration of electricity, no single preferred solution has yet been identified. The cost of electrochemical energy storage devices has declined, but other options such as underground hydrogen stores being charged and discharged with use of fuel cells or gas turbines may turn out to be the most attractive solution. Storage technologies cannot be avoided if renewable energy is to become a 100% solution, due to the variations in resource flow that is obvious for wind and solar radiation, the latter being particularly uncorrelated with energy demand due to day–night and seasonal variations, plus the effect of passing cloud cover.
Quite substantial updates and additions are made in Chapter 6, dealing with scenarios for supply–demand matching in different parts of the world. New scenarios has been added, for the North American countries, for Japan and Korea, and particularly for China, where a model highlighting the continuation of the bold steps already made over the last decade has been based on dividing China into four parts, according to resource availability and demand density considerations. This model determines the requirement for power transmission between regions of China as well as further energy storage needs, that will allow Chinese energy demands to be fully covered by renewable resources.
The details of the most recent climate-related impact estimations presented in Chapter 7 are also used to update the earlier energy system life-cycle analysis examples and add a few new ones. Finally, Chapter 8 again summarizes the overall conditions for success of the transition away from fuel-based energy systems, including getting rid of false economic paradigms and creating a new spirit of international cooperation based on equity and welfare rather than on the present exploitation and inequality-creating behavior of international traders and the selfish politics of many national leaders.
Gilleleje, October 2016