Environmental Engineering Reference
In-Depth Information
What we are eating through, among other things, is our readily available, rela-
tively inexpensive source of energy. The point is that we can, like the grasshopper,
gobble it all up until it is all gone or we can find alternatives—renewable alterna-
tives of energy. The nation is aggressively developing the capacity to meet some of
our energy needs through biofuels and biopower. The Energy Independence and
Security Act of 2007 (EISA) called for the use of 36 billion gallons per year (BGY)
of renewable fuels by 2011 and established new categories of renewable fuels, each
with specific volume requirements and life-cycle greenhouse gas (GHG) perfor-
mance thresholds (USDA, 2012).
One of the promising sources of energy is biomass (biofuel) or bioenergy (bio-
power).
Biomass
is the feedstock used to produce
bioenergy
, a general term for
energy derived from materials such as straw, wood, or animal wastes (i.e., biomass),
which, in contrast to fossil fuels, were living matter relatively recently. Such materi-
als can be burned directly as solids (biomass) to produce heat or power, but they can
also be converted into liquid biofuels. In the last few years, interest has grown con-
siderably in bioenergy fuels such as biofuels (biodiesel and bioethanol) that can be
used for transport. At the moment, transport has taken center stage in our search for
renewable, alternative fuels to eventually replace hydrocarbon fuels. Unlike biofuels,
solid biomass fuel is used primarily for electricity generation or heat supply.
Even though we have stated that bioenergy is a promising source of energy for the
future, it is rather ironic whenever the experts (or anyone else for that matter) make
this point without qualification. Keep in mind that only 100 years ago our economy
was based primarily on bioenergy from biomass, or carbohydrates, rather than from
hydrocarbons. In the late 1800s, the largest selling chemicals were alcohols made
from wood and grain, the first plastics were produced from cotton, and about 65%
of the nation's energy came from wood (USDOE, 2004). By the 1920s, the economy
started shifting toward the use of fossil resources, and after World War II this trend
accelerated as technology breakthroughs were made. By the 1970s, fossil energy was
established as the backbone of the U.S. economy, and all but a small portion of the
carbohydrate economy remained. In the industrial sector, plants accounted for about
16% of input in 1989, compared with 35% in 1925.
Processing costs and the availability of inexpensive fossil energy resources con-
tinue to be driving factors in the dominance of hydrocarbon resources. In many
cases, it is still more economical to produce goods from petroleum or natural gas
than from plant matter. This trend is about to shift dramatically as we reach peak oil
and as the world continues to demand unprecedented amounts of petroleum supplies
from an ever-dwindling supply. The technological advances being made in the bio-
logical sciences and engineering, political change, and concern for the environment
have begun to swing the economy back toward carbohydrates on a number of fronts.
Consumption of biofuels in vehicles, for example, rose from zero in 1977 to nearly
1.5 billion gallons by 1999. The use of inks produced from soybeans in the United
States increased fourfold between 1989 and 2000 and is now at more than 22% of
total use (Morris, 2002).
Technological advances are also beginning to make an impact on reducing
the cost of producing industrial products and fuels from biomass, making them
more competitive with those produced from petroleum-based hydrocarbons.
