Preface

This textbook is an effort to provide a foundational resource for college students with an interest in applying green engineering principles into their own specific discipline. It is written from an engineering perspective with a focus on the fundamental science and technology while also commenting briefly on key interdisciplinary issues in economics, public policy, politics, psychology, and the social sciences that intersect green engineering. Additional resources related to these complex systems and non-engineering issues are provided for students to delve deeper than the scope of this course allows.

The overarching goal of this text is to help students understand the complex connections between energy, water, food, and the infrastructure that supports these systems. We call this “green engineering” but it can also be thought of more broadly as “systems engineering” with a focus on the environmental impacts which are critical design constraints for societies consider in order to survive and thrive into the future.

Chapter 1 is an overview of Green Engineering with a focus on connections of the environment, society, and the economy – the so-called Triple Bottom Line. To build a common framework of environmental understanding for students from a wide variety of backgrounds, this chapter includes a brief overview of ecosystems, natural capital and ecosystems services which have often been de-emphasized in engineering design since the industrial revolution leading to many undesirable consequences.

Chapter 2 focuses on energy systems, specifically the sources of energy and energy production methods, that have driven the world’s growth since the industrial revolution. This chapter is dominated by discussion of fossil fuel energy sources and steam-generated power plants which are fundamentally unsustainable due to resource limitations and associated environmental pollution. Nuclear power systems are also discussed in this chapter, though they are not fossil fuel and their sustainability issues are of a different nature.

Chapter 3 focuses on the rethinking and transition underway of our current energy systems to more sustainable options including renewables (solar, wind, hydro, geothermal, and biomass). Biomass and biofuels are substantially different than most of the other energy sources due to the more complex and difficult processing needed to convert plants into various fuel sources using a variety of processing methods.

Chapter 4 provides an overview of current and future battery/storage systems that are necessary for the transition away from fossil fuels due to the to the inherent intermittency and storage issues with several of the primary renewable energy sources. Different types of batteries/storage are explained along with their advantages and limitations.

Chapter 5 considers Transportation systems which includes the traditional fossil fuel options based on petroleum as well as the newer options of biofuels, natural gas, hydrogen, and electricity. Batteries, primarily those which are electrochemical in nature, are revisited here from an applications perspective given their current dominance in the electrification of transportation.

Chapter 6 considers Buildings, Cities, and Communities and their connection to the concepts in the previous chapters to power our houses, workplaces, schools, and communities. The design of this long-term infrastructure depends upon the technology in the earlier chapters as well as dictates the requirements and opportunities.

Chapter 7 considers Water systems which are directly connected to both energy and the environment. This chapters discusses the different sources of water, the use of water throughout society, and the challenges of keeping this water clean and available for both humans and ecosystems which depend upon it.

Chapter 8 considers Food and Agriculture systems which interconnects both energy and water in what are currently know as Food-Energy-Water System (FEWS). Like energy and water, society often takes food systems for granted and complex relationship between these 3 topics is necessary for abundant, healthy, and affordable food for all in the future.

These chapter topics are all covered at a relatively introductory level targeting advanced undergraduate students. Again, the focus is on engineering fundamental and concepts with brief diversions into other interdependent fields. The topics do not follow a strictly linear path through green engineering since they are so deeply interconnected. We could easily rearrange the order of most of these chapters to make the same key points and cover the same learning objectives. We have tried to arrange these topics in a way that tells a coherent story, but you should not be surprised if you are thinking about concepts and asking questions about future chapters in the early chapters. This is encouraged and normal, but can be challenging if you are stuck thinking in a linear matter.

We have tried to format this text for ease of understanding and learning. In the Background section of each chapter, we provide Learning Objectives and Key Questions so you can immediately see the main concepts of the chapter. We also provide a Primer with key definitions for each chapter that will help students with less background on some of the topics. The chapters also include specific examples and practice problems in highlighted boxes. More examples and problems should supplement those in the text which has limited space to touch on all aspects of the topics. As much as possible, resources mentioned in the text are either linked and/or referenced at the end of each chapter. It is important to look at the chapter figures and their captions in detail as they often contain key concepts, data, and opportunities for critical thinking.

Note that the topics in this text are changing rapidly as new technology and science evolve. It will not be uncommon to find slightly newer or updated data with a bit of online research and this is important to understand that the science and engineering are not static and the trends from year to year often evoke important and interesting questions.

This textbook has grown out of a Green Engineering course taught by us for more than a decade at Virginia Tech. As such, you will find some specific examples and data from this university, state, and country. The concepts, however, will hold wherever you may be located and we encourage you to research examples and data specific to your location and locations of interest to you as the technologies and details for many systems are highly depending on location.