Page 78 - Advances in Eco-Fuels for a Sustainable Environment

Prospects of biodiesel feedstock as an effective ecofuel source and their challenges 55

feedstock [21]. About 6.6 million tonnes (34%) of edible oil were estimated for world-
wide biodiesel production from 2004 to 2007 [19].
The feedstock for biodiesel production can vary from country to country,
depending on the availability of certain types of vegetable oil [22]. The primary oil
used to make biodiesel fuel in the United States is soybean oil while in Europe it
is rapeseed oil, in Malaysia is palm oil, and in India it is Jatropha [23]. Some of these
edible oilseeds are discussed in details in the following subsections. The availability of
these feedstocks depends largely on geographical location, which dictates the preva-
iling climatic conditions for their cultivation. Unlike maize/corn and groundnut/pea-
nut, which can be grown anywhere on the planet under all kinds of climatic conditions,
the majority of these feedstocks have specific regions on the planet where they can be
suitably cultivated.
Sesame, olive, moringa, cotton, palm, and coconut trees are cultivated in the tropical
(delimited in latitude by the Tropic of Cancer in the Northern hemisphere at 23.5°N
and by the Tropic of Capricorn in the Southern hemisphere at 23.5°S) and subtropical
(between the tropic and the temperate zones, usually delimited in latitude between the
tropic and the temperate zones usually delimited in latitude between 23.5° and 35° of
north and south of the Equator, respectively. Hazelnut and walnut can be cultivated in
both the cold and warm temperate regions while sesame, almond, olive, and Chinese
tallow grow well in warm temperate zones and rapeseed/canola, sunflower, soybean
and poppy grow well in the cold temperate zones. In addition, hazelnut, almond, olive,
and poppy can also be cultivated in the Mediterranean regions. Safflower thrives
well in the Mediterranean regions.
In terms of precipitation or rainfall requirements, we have the arid climate (desert)
receiving <10in. or 25cm per annum of precipitation, the semiarid climate that
receives 10–20in. or 25–50cm of precipitation per annum, and humid climates
that receive 20–50in. or 50–125cm per annum of precipitation. While cottonseed,
groundnut, maize, sesame, rapeseed, and soybean can thrive well in all of the arid,
semiarid, and humid climate regions, hazelnut, moringa, Chinese tallow, and coconut
can only thrive well in semiarid and humid regions but not in arid regions while palm
trees and walnut thrive well only in humid regions. Table 3.1 summarizes the climatic
requirements of each of these edible prospective feedstocks.
Based on life cycle, edible oil crops can be grouped into annual crops, biennial
crops, and perennial crops. An annual crop takes a few months or at most a year to
complete its life cycle, whereas a biennial plant takes 2years to complete its life cycle.
Biennial plants germinate, grow, and survive through the first planting season/year
and in the second year will grow more, bloom, and die. Perennial crops require more
than two planting seasons/years to complete their life cycles. Biennials are less com-
mon than both annuals and perennials. Global annual edible oil crops include soybean
(Glycine max), sunflower (Helianthus annuus), sesame, safflower, groundnut/peanut,
corn/maize, and poppy. Global perennial edible oil crops include oil palm, coconut,
olive, Chinese tallow, hazelnut, almond, moringa, cotton, walnut, and bay laurel.
Rapeseed can be classified as either an annual or a biennial crop depending on the
variety. Cotton plants are perennial crops but are always grown as annuals to prevent
disease and help combat the boll weevil. Many perennial crops yield far better than the