Transport fuel in the USA

The scale of the problem of providing a significant replacement for fossil fuels using first-generation biofuels is illustrated in Table 8.4. The agricultural land required to supply 15% of the US transport fuels for a number of crops has been calculated. For

Crop

Oil yield (l/ha)

Area needed (million ha)

Percentage of US crop area

Maize (ethanol)

172

462

178

Soybean (biodiesel)

446

178

67

Rapeseed (biodiesel)

1,190

67

42

Jatropha sp. (biodiesel)

1,892

42

13

Oil palm (biodiesel)

5,950

13

7.2

Algae/cyanobacteriaa

(biodiesel)

59,000

1.3

0.72

aOil content 30%.

the temperate crops such as soybean and rapeseed, this would require 67 and 42% of the agricultural land, respectively, and even with the highest yield crop, oil palm, 7.2% of the land would be needed. Unfortunately crops such as oil palm are unsuit­able for growth in temperate climates. The table does make a good case for biodiesel from alternative sources such as microalgae.