Introduction and context: global biomass resources - Biomass as Energy Source: Resources, Systems and Applications - page 22

Figure 1.14. Marshland in San Francisco, USA (photo E. Dahlquist).
million tonne/y. This gives 233.9 million tonne/y (2009) of all major crops altogether. The national
directorate of wheat research in India states that 50% of the calories are at an average coming
from wheat to the Indian population (Singh, 2009). The productivity with respect to wheat has
increased from 0.9 tonnes/ha in 1965 to 3 tonnes/ha/per y today at an average. The increase
has been due to selection of suitable clones for each type of soil and other conditions. This of
course is very promising. The highest yields are in Punjab and Haryana with 4-4.3 tonnes/ha
per y, while Karnataka has only 0.7 tonnes/ha per y. This shows that there is still a potential
for improvements. Today the production is 67 kg/capita, while the demand is 73 kg/capita. With
further improvements, Singh believes there will be a balance already within ten years. A potential
threat still is rusts, leaf blight and insects as well as climatic issues.
1.5.4 USA
Huber and Dale (2009) made a review of US biomass potential especially for the purpose as fuels
for vehicles. The authors presented the following figures: 428 million tonnes agricultural waste,
377 million tonnes energy crops, 368 million tonnes forest products, 87 million tonnes corn and
other grains and 106 million tonnes other type of organic residues. Totally, this gives 1366 million
tonnes/year of crop residues. They also discuss possible energy crops as a complement, where the
following are considered to be of highest interest in the US: switch grass, sorghum, miscanthus
and energy cane. The authors estimate that these residues and crops could produce 3.5 billion
barrels of oil equivalents, which is roughly 50% of the 7.1 billion barrels of oil used today in
the US. If we just assume that these crops have a higher heating value ( HHV ) of 5.4MWh/tonne,
it means 7376TWh/y. In many areas in the western US we see relatively arid biotopes. In the
marshland area close to San Francisco (Fig. 1.14), we can see examples of this as well as the typical
mountain areas with scarce forest like in Figure 1.15 with Golden Gate Bridge in the foreground.
There are also more fruitful areas with forests in the west part of the US as illustrated in
Figure 1.16 in Santa Barbara. Here many different species exist side by side.