What is Biodiesel?
[[File:Biodiesel-2.jpg|thumb|Biodiesel]] [[File:Biodieselraffinerie-01.JPG|thumb|Biodiesel refinery in Austria, near fields that can grow oilseed]] [[File:Biodiesel_3.jpg|thumb|Older diesel Mercedes are popular for running on biodiesel]] [[File:Diesel prices.jpg|thumb|In some countries biodiesel is less expensive than conventional diesel]] '''Biodiesel''' is a type of [[fuel]] prepared by changing [[vegetable oil]], animal fat, special types of [[algae]] and possibly even [[sewage]]. It is considered a type of [[renewable energy]], since it all comes from living plants and animals. It can be used to power an engine, usually for [[vehicle]]s, including [[airplane]]s. It replaces [[diesel]] that comes from [[petroleum]], a type of [[fossil fuel]]. <ref>{{cite web|title=Intro to Biodiesel|url=http://www.biodiesel.org/|publisher=Biodiesel.org|accessdate=15 April 2013}}</ref> [[Biogas|Biofuel]] prepared from [[biomass]] is different since it does not start from oil and uses a different [[chemical]] process to make the fuel. ==Advantages and disadvantages== Biodiesel is much cleaner and has less [[pollution]] than diesel fuel made from fossil fuels. It also acts as a solvent (like soap). In fact, it cleans the engine so much that it might pull out old dirt in the engine and clog up the filters. After the filters are replaced then it is fine.{{Citation needed|date=May 2023}} In the [[United States]] and several other places, new laws say that regular diesel fuel must be low in sulfur. This gets rid of pollution, especially [[acid rain]], but it also makes the fuel less slippery. Adding in biodiesel helps keep the fuel slippery and the engine running smoothly.<ref>{{cite web|title=Biodiesel advantages and considerations|url=http://www.afdc.energy.gov/fuels/biodiesel_benefits.html|publisher=U.S. Department of Energy|accessdate=15 April 2013}}</ref> Most biodiesel comes from plants.<ref>{{Cite web |title=Biomass to Diesel: A Sustainable Alternative to Fossil Fuels |url=https://whatsbiomass.com/biomass-to-dies