And it remains so to this day when compared to biodiesel, a fuel made from oils of plants and animal fat.

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Much of the hedging is carried out with WTI contracts but the actual fuel is mainly refined from pricier oils.

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These natural oils and biomaterials are tailored not only for fuel production, but also as replacements for fossil-derived petroleum and a variety of natural plant oils and compounds, making them useful in a wide range of products: from oleochemicals, to cosmetics, to foods.

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Foster came up with a system of "driving the building" with renewable vegetable oils, such as rapeseed, for fuel.

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Further, heavy crude oils do not produce as much gasoline or fuel oil as light crude oil.

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The worst offenders are palm oils, which may have ten times the carbon emissions of normal diesel fuel derived from petroleum if the palm is grown on converted rainforest land.

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