The need for sustainable energy is growing at an increasing rate with the alarmingly high rate of increase in population coupled with the fast growth of urbanization. By 2050 the world population is estimated to be seven billion computed at a conservative rate of growth. By 2100, the number is projected to be over ten billion by another estimate. The source of fossil fuels being predominantly used over time will face depletion around the end of this century unless non-conventional energy sources are put in place. Besides depletion, fossil fuel use is constrained by geo-political issues and threat of greenhouse gas emission. Among the alternative energy sources, bioenergy is emerging as the most promising as compared to atomic, solar, and wind. Bioenergy including bioethanol and biodiesel can be produced from cellular biomass, starch, sugar, and oil derived from several plants and plant products in huge amounts once the required strategies and technologies are formulated and validated for commercialization in cost-effective ways.

Scientific exploratory research conducted during the last few years has identified a large number of plants as potential sources of bioenergy. These include maize, sorghum, switchgrass, canola, soybean, and sugarcane among field crops; eucalyptus and poplar among forest trees; and jatropha, oil palm and cassava among plantation crops. Several other promising field crops including Brachypodium, minor oilseeds, sugarbeet, sunflower, and sweetpotato; forest trees including diesel trees and shrub willow; plantation crops such as Paulownia; many lower plants; and even vegetable oils, organic farm waste and municipal sludge have been found to be promising. Therefore, ‘fuel’ has made its place in the list of principal agricultural commodities along with food and fiber.

Significant studies have also been conducted in natural and social sciences to facilitate utilization of plants and plant products as the most potential source of bioenergy. In bioenergy crops, research has been carried out on genetics, genomics and breeding for relevant traits employing traditional and molecular breeding, genomics-assisted breeding, and genetic engineering. Physiological works have been done for in planta production of cell-degrading enzymes and enzymatic conversion of cell walls into biofuels. Significant advancement has been made on the works on post-harvest technologies and chemical engineering, fuel quality, and

vi Compendium of Bioenergy Plants: Switchgrass

greenhouse gas impacts of bioenergy. Most importantly, economics, public policies, and perceptions have also been critically examined.

There are, at present, only a few books on bioenergy crop plants available. I have myself edited a book recently with two other co-editors for the CRC Press of the Taylor and Francis Group. This book entitled ‘Handbook of Bioenergy Crop Plants’ elucidates on the general concepts of and concerns about bioenergy crop production, genetics, genomics and breeding of commercialized bioenergy crop plants, and emerging bioenergy crops or their groups besides deliberations on unconventional biomass resources such as vegetable oils, organic waste and municipal sludge.

As expected, there is also an array of research and review articles on the basic concepts, strategies and means of utilization of bioenergy crop plants and their products in scientific journals, web sites, newsletters, newspapers, etc. However, there is no endeavor to present any compilation about all the relevant aspects related to particular bioenergy crop plants already commercialized or having potential to be commercialized in near future. The present book series will hopefully fill up that vacuum. This is particularly important as the subject of bioenergy has already occupied its place in academia, research labs, and public life. This was the underlying force behind conception of a book series on ‘Compendium of Bioenergy Crop Plants’.

At the outset, I formulated the tentative outline for 15 chapters to maintain more or less uniformity throughout the volumes of the compendium. These included basic information on the crops; anatomical and physiological researches relevant to feedstock; special requirements related to agricultural and industrial infrastructure; elucidation on genetics, genomics and breeding of bioenergy traits; public platforms for sharing results and building initiatives; role of public and private agencies in fostering research and commercialization; regulatory, legal, social and economic issues; general concerns and their compliance; and also future prospects and recommendations. However, the volumes of this compendium are devoted to various crop plants and obviously the concerned volume editors had to improvize on the contents of the respective volumes based on the unique information available and specific requirements. Thus, each volume of this compendium has the ‘stand-alone’ potential at the same time, thanks to the excellent balancing job performed by the volume editors. Fortunately most, if not all, of the volume editors have long standing association with me as an author of a chapter in some other book, or volume editor of another book series or colleague in a research platform. Therefore, it has been highly comfortable and enriching for me to work with them again for this compendium. I take this opportunity to express my heartiest gratitude to them for offering me this opportunity. The authors of the chapters for each of the volumes have produced high

quality deliberations both in terms of comprehensive contents and lucid write-ups. As the series editor, I must join with my volume editors to extend our thanks to the authors of the chapters for their elegant contributions as well as sincere cooperation all along.

This compendium was originally conceptualized by my wife and colleague, Phullara. She had meticulously reviewed the relative importance and quantum of works accomplished in the commercialized and promising bioenergy crops plants and had eventually identified the leading bioenergy crop plants to which the individual volumes of this compendium are devoted to. She was always there for help in editing this compendium similar to several other book series containing over sixty books published or in press. Expressing just thanks will not do justice to her contribution to this book project. I have, therefore, dedicated this compendium to her in recognition of her contributions to this book project and also for all her support, advice and inspiration for all my academic activities besides shouldering most of our domestic loads, taking the major responsibility to navigate our family and nourish our three growing kids, Papai, Titai and Kinai, as that provided me with enough extra time for my book editing jobs in addition to my professional duties.

Chittaranjan Kole