Biomass Feedstock Production and Provision: Overview, Current Status, and Challenges - Engineering and Science of Biomass Feedstock Production and Provision - page 2

1.1 Introduction

Availability of energy is very critical to the survival, well-being, and development
of the society. The industrial revolution spurred tremendous development during the
past century and has led to unprecedented energy demands throughout the globe.
The rising global population has further intensified the energy-consumption
patterns. The majority of the world's energy demand is presently being met by
nonrenewable fossil fuels, mainly coal, petroleum, and natural gas [ 1 ]. However,
these fuel reserves are rapidly depleting [ 2 ]. Moreover, emissions resulting from
fossil fuel consumption, such as CO 2 , CH 4, and N 2 O, are believed to be driving the
global warming trends [ 3 ], as well as being the cause of acid rain and various health
problems for humans and animals. There are also implications for the national economy
and security of various countries. The long-term sustainability of the prevailing
energy-consumption practices, therefore, is being questioned.
These concerns have been instrumental in the drive towards alternate, renewable,
regional, and “clean” sources of energy, such as biomass, solar, wind, and hydro.
Although the overall contribution of renewable energy is presently not signifi cant, it
is expected that with the development of more effi cient technologies, these energy
sources will become cost-competitive with the conventional nonrenewable sources.
Among these renewable sources, biomass holds a distinct advantage for primarily
two reasons. First, the biomass-based resources can be converted to liquid fuels
such as ethanol and butanol, which can readily fi t into the existing transportation
infrastructure, thereby requiring minimal modifi cations. Since the transportation
sector is a major consumer of fossil fuels, biomass-based fuels can make a signifi -
cant impact. Second, the availability of biomass-based resources is relatively stable
and predictable as compared to wind and solar [ 4 , 5 ]. Biomass can also be stored for
later use. In addition to this, biomass can also be converted to heat by direct com-
bustion, power by direct combustion or co-fi ring with coal, and other value-added
products and chemicals, such as glycerol and lactic acid [ 6 ].
There are primarily two sources of biomass: forestry and agriculture. For each of
these sources, the available resources can be classifi ed as primary, secondary, and
tertiary [ 4 ]. Currently, the production of biofuels and bioproducts is being achieved
mainly from the conventional agricultural food crops such as sugarcane in Brazil,
corn and soybean in the United States, as well as Europe, and palm oil in Asia. The
agricultural practices to produce these crops have improved substantially over cen-
turies, and the processes to convert these sources into fuel and products are also well
understood. These systems, therefore, are economically viable. However, the use of
these food crops for fuel production has spurred the “food vs. fuel” debate in recent
years [ 7 ]. It has been argued that use of these crops for fuel production is increasing
food prices and impacting the availability of food resources. Moreover, cascading
effects of increased fuel production are leading to indirect land use change in differ-
ent parts of the world, thereby also mitigating the environmental and social benefi ts
of biofuels [ 8 ]. Therefore, lignocellulosic biomass, such as dedicated perennial
grasses, agricultural crop residue, forestry residue, and short rotation woody bio-
mass, have emerged as the more sustainable biomass resources [ 4 , 9 ].