Green diesel, also known as renewable diesel, is a form of diesel fuel which is derived from renewable feedstock by using biomass to liquid

Biomass to liquid

Biomass to Liquid or BMtL is a multi-step process which produces liquid biofuels from biomass:The process uses the whole plant to improve the carbon dioxide balance and increase yield....

 or vegetable oil refining

Vegetable oil refining

Vegetable oil can be used as feedstock for an oil refinery. There it can be transformed into fuel by hydrocracking or hydrogenation . These methods can produce gasoline, diesel, and propane. Some commercial examples of vegetable oil refining are NExBTL, H-Bio, and the ConocoPhilips process...

 technologies. Based on its feedstock it could be classified as biodiesel

Biodiesel

Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl esters. Biodiesel is typically made by chemically reacting lipids with an alcohol....

; however, based on the processing technology and chemical formula green diesel and biodiesel are different products. While biodiesel is processed using transesterification

Transesterification

In organic chemistry, transesterification is the process of exchanging the organic group R″ of an ester with the organic group R′ of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst...

, green diesel is processed by the traditional fractional distillation

Fractional distillation

Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. It is a special type of distillation...

 like fossil origin diesel fuel (petrodiesel).

Feedstock

Green diesel feedstock can be sourced from a variety of oils including canola

Canola

Canola refers to a cultivar of either Rapeseed or Field Mustard . Its seeds are used to produce edible oil suitable for consumption by humans and livestock. The oil is also suitable for use as biodiesel.Originally, Canola was bred naturally from rapeseed in Canada by Keith Downey and Baldur R...

, algae

Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...

, jatropha

Jatropha

Jatropha is a genus of approximately 175 succulent plants, shrubs and trees , from the family Euphorbiaceae. The name is derived from the Greek words ἰατρός , meaning "physician," and τροφή , meaning "nutrition," hence the common name physic nut. Mature plants produce separate male and female...

 and salicornia in addition to tallow

Tallow

Tallow is a rendered form of beef or mutton fat, processed from suet. It is solid at room temperature. Unlike suet, tallow can be stored for extended periods without the need for refrigeration to prevent decomposition, provided it is kept in an airtight container to prevent oxidation.In industry,...

.

Green diesel was used to power at least one vehicle during a transportation showcase at the 2009 United Nations Climate Change Conference

2009 United Nations Climate Change Conference

The 2009 United Nations Climate Change Conference, commonly known as the Copenhagen Summit, was held at the Bella Center in Copenhagen, Denmark, between 7 December and 18 December. The conference included the 15th Conference of the Parties to the United Nations Framework Convention on Climate...

 in Copenhagen, Denmark in December 2009.

Also in December 2009, the South Dakota School of Mines and Technology

South Dakota School of Mines and Technology

The South Dakota School of Mines and Technology is a public institution of higher learning in Rapid City, South Dakota governed by the South Dakota Board of Regents. Founded in 1885 as the Dakota School of Mines, Tech offers degree programs in engineering and science fields. 2,354 students were...

 received a $1M US grant from the United States government, in part to do research on green diesel, along with biodiesel and other bio fuel research for the United States Air Force

United States Air Force

The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

.

“Green Diesel” as commonly known in Ireland should not be confused with dyed green diesel sold at a lower tax rate for off-road use, using the dye allows custom officers to determine if a person is using the cheaper diesel in higher taxed applications such as commercial haulage or cars.

Technology

At this stage the only commercial scale green diesel refinery process is the UOP

UOP LLC

UOP LLC, formerly known as Universal Oil Products, is a multi-national company developing and delivering technology to the petroleum refining, gas processing, petrochemical production, and major manufacturing industries....

/Eni

Eni

Eni S.p.A. is an Italian multinational oil and gas company, present in 70 countries, and currently Italy's largest industrial company with a market capitalization of 87.7 billion euros , as of July 24, 2008...

 "Ecofining" process.

Smaller scale refining can be carried out using technology from Renewable Fuel Products, Inc.