Environmental Engineering Reference
In-Depth Information
was using potatoes, sugar, and rice wine to produce alcohol for fuel (Yergin 1992). After the oil cri-
ses of the 1970s, Brazil and the United States enacted policies that successfully encouraged ethanol
production as a gasoline substitute. More recently, legislation in the United States set an ambitious
goal of 1.36 × 10
11
L/year of ethanol production by 2022, with most of that to be made from cel-
lulose. In the past decade, the EU, especially Germany, has also greatly increased its production
of biofuels, particularly biodiesel. In 2008, 67 × 10
9
L of ethanol and 12 × 10
9
L of biodiesel were
produced worldwide, compared with 39 × 10
9
and 6 × 10
9
L, respectively, produced in 2006 (REN21
2009). Table 12.1 shows the top 15 producing countries of biofuels as of 2008.
There are many types of biofuels, the two most common of which are the liquid fuels ethanol
and biodiesel (Solomon and Johnson 2009a). Ethanol is produced from grains (especially corn) and
crops with high sugar content, such as sugarcane and sugarbeets. To process the starch in grains to
alcohol, seven steps are required: milling, liquefaction, saccharification, fermentation, distillation,
dehydration, and denaturing. Processing crops with high sugar content is cheaper than process-
ing grains and it requires five steps: milling, pressing, fermentation, distillation, and dehydration
(Solomon et al. 2009). Other alcohols, especially methanol, propanol, and butanol, can also be
manufactured. Alcohol can also be processed from cellulosic-based feedstocks, including wood,
agricultural residues, straws, and grasses. Although little cellulosic ethanol is currently produced
commercially because of the immature technology and high costs involved, capacity to produce
cellulosic ethanol will grow rapidly in the next decade.
Biodiesel is produced primarily from vegetable oils, but it can also be created from animal
fats. Common crops include rapeseed, palm, soy, sunflower, and peanut. After oil is extracted from
taBle 12.1
Global Biofuels Production in 2008 for the top 15
Producing countries
Billion liters
country
Fuel ethanol
Biodiesel
total
United States
34
2.0
36
Brazil
27
1.2
28
France
1.2
1.6
2.8
Germany
0.5
2.2
2.7
China
1.9
0.1
2.0
Argentina
-
1.2
1.2
Canada
0.9
0.1
1.0
Spain
0.4
0.3
0.7
Thailand
0.3
0.4
0.7
Colombia
0.3
0.2
0.5
Italy
0.13
0.3
0.4
India
0.3
0.02
0.3
Sweden
0.14
0.1
0.2
Poland
0.12
0.1
0.2
United Kingdom
-
0.2
0.2
EU total
2.8
8
10.8
World total
67
12
79
Source:
REN21, Renewables Global Status Report: 2009 update. Renewable
Energy Policy Network for the 21st Century Secretariat, Paris,
2009. Available at www.martinot.info/RE_GSR_2009_Update.pdf
(accessed July 17, 2009). With permission.
