• Virgin oil feedstock; rapeseed and soybean oils are most commonly used, though other crops such as mustard, palm oil, hemp and even algae show promise.
• Waste vegetable oil (WVO).
• Animal fats including tallow, lard, and yellow grease.
• Non edible oils like Jatropha, Neem Oil, Castor Oil etc.

• Soybean: 40 to 50 US gal/acre (40 to 50 m³/km²)
• Rapeseed: 110 to 145 US gal/acre (100 to 140 m³/km²)
• Mustard: 140 US gal/acre (130 m³/km²)
• Jatropha: 175 US gal/acre (160 m³/km²)
• Palm oil: 650 US gal/acre (610 m³/km²) [2]
• Algae: 10,000 to 20,000 US gal/acre (10,000 to 20,000 m³/km²)

Additional factors must be taken into account, such as: the fuel equivalent of the energy required for processing, the yield of fuel from raw oil, the return on cultivating food, and the relative cost of biodiesel versus petrodiesel. A 1998 joint study by the U.S. Department of Energy (DOE) and the U.S. Department of Agriculture (USDA) traced many of the various costs involved in the production of biodiesel and found that overall, it yields 3.2 units of fuel product energy for every unit of fossil fuel energy consumed. [3] That measure is referred to as the energy yield.

Some nations and regions that have pondered transitioning fully to biofuels have found that doing so would require immense tracts of land if traditional crops are used. Considering only traditional plants and analyzing the amount of biodiesel that can be produced per acre of cultivated land, some have concluded that it is likely that the United States, with one of the highest per capita energy demands of any country, does not have enough arable land to fuel all of the nation's vehicles. Other developed and developing nations may be in better situations, although many regions cannot afford to divert land away from food production. For third world countries, biodiesel sources that use marginal land could make more sense, e.g. Jatropha Trees grown along roads & Railway tracts and other areas.

The direct source of the energy content of biodiesel is solar energy captured by plants during photosynthesis.

When straw was left in the field, biodiesel production was strongly energy positive, yielding 1 GJ biodiesel for every 0.561 GJ of energy input (a yield/cost ratio of 1.78).

When straw was burned as fuel and oilseed rapemeal was used as a fertilizer, the yield/cost ratio for biodiesel production was even better (3.71). In other words, for every unit of energy input to produce biodiesel, the output was 3.71 units (the difference of 2.71 units would be from solar energy).
Biodiesel is becoming of interest to companies interested in commercial scale production as well as the more usual home brew biodiesel user and the user of straight vegetable oil or waste vegetable oil in diesel engines. Homemade biodiesel processors are many and varied.

Availability

Biodiesel is commercially available in most oilseed-producing states in the United States. As of 2005, it is somewhat more expensive than fossil diesel, though it is still commonly produced in relatively small quantities (in comparison to petroleum products and ethanol). Many farmers who raise oilseeds use a biodiesel blend in tractors and equipment as a matter of policy, to foster production of biodiesel and raise public awareness. It is sometimes easier to find biodiesel in rural areas than in cities. Similarly, some agribusinesses and others with ties to oilseed farming use biodiesel for public relations reasons. As of 2003 some tax credits are available in the U.S. for using biodiesel. In 2004 almost 30 million gallons (110,000,000 l) of commercially produced biodiesel were sold in the U.S.

Brazil opened a commercial biodiesel refinery in March 2005. It is capable of producing 12 million liters (3.2 million gallons) per year of biodiesel fuel. Feedstocks can be a variety of sunflower seeds, soybeans, or castor beans. The finished product will be currently a blend of gas oil with 2% biodiesel and, after 2011, 5% biodiesel, both usable in unmodified diesel engines.