Biodiesel
<p ><b>Biodiesel</b> refers to a vegetable oil- or animal fat-based <a href="http://en.wikipedia.org/wiki/Diesel_fuel" title="Diesel fuel" >diesel fuel</a> consisting of long-chain <a href="http://en.wikipedia.org/wiki/Alkyl" title="Alkyl" class="mw-redirect" >alkyl</a> (<a href="http://en.wikipedia.org/wiki/Methyl" title="Methyl" class="mw-redirect" >methyl</a>, <a href="http://en.wikipedia.org/wiki/Propyl" title="Propyl" >propyl</a> or <a href="http://en.wikipedia.org/wiki/Ethyl_group" title="Ethyl group" >ethyl</a>) <a href="http://en.wikipedia.org/wiki/Ester" title="Ester" >esters</a>. Biodiesel is typically made by chemically reacting <a href="http://en.wikipedia.org/wiki/Lipids" title="Lipids" class="mw-redirect" >lipids</a> (e.g.,<a href="http://en.wikipedia.org/wiki/Vegetable_oil" title="Vegetable oil" class="mw-redirect" >vegetable oil</a>, animal fat (<a href="http://en.wikipedia.org/wiki/Tallow" title="Tallow" >tallow</a><sup id="cite_ref-NRA1_0-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Biodiesel#cite_note-NRA1-0" >[1]</a></sup><sup id="cite_ref-AusBiofuels_1-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Biodiesel#cite_note-AusBiofuels-1" >[2]</a></sup>)) with an <a href="http://en.wikipedia.org/wiki/Alcohol" title="Alcohol" >alcohol</a> producing <a href="http://en.wikipedia.org/wiki/Fatty_acid_ester" title="Fatty acid ester" >fatty acid esters</a>.</p>
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Biodiesel is meant to be used in standard diesel engines and is thus distinct from the vegetable and waste oils used to fuel<i>converted</i> diesel engines. Biodiesel can be used alone, or blended with petrodiesel. Biodiesel can also be used as a low carbon alternative to <a href="http://en.wikipedia.org/wiki/Heating_oil" title="Heating oil" >heating oil</a>.</p>
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The <a href="http://en.wikipedia.org/wiki/National_Biodiesel_Board" title="National Biodiesel Board" >National Biodiesel Board</a> (USA) also has a technical definition of "biodiesel" as a mono-alkyl ester.<sup id="cite_ref-NBB_2-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Biodiesel#cite_note-NBB-2" >[3]</a></sup></p>