Biodiesel
Biodiesel is one of the most popular biofuels in use today, especially for the do it yourself crowd. Biodiesel is defined as being:
a non-petroleum-based diesel fuel consisting of short chain alkyl (methyl or ethyl) esters, made by transesterification of vegetable oil, which can be used (alone, or blended with conventional petrodiesel) in unmodified diesel-engine vehicles.
The main problem stopping biodiesel from going mainstream is the short supply of high yield feedstocks that can be processed into high quality biodiesel. Below is a breakdown of the gallon per acre yields from the more common feedstocks used to produce biodiesel:
- Chinese tallow: 503 gpa- 970 gpa
- Palm oil: 508 gpa
- Coconut: 230 gpa
- Rapeseed: 102 gpa
- Soy: 59.2-98.6 gpa in Indiana (Soy is used in 80% of USA biodiesel)
- Peanut: 90 gpa
- Sunflower: 82 gpa
As you can see the most common feedstock (soy) only yields 60-100 gallons of biodiesel per acre. Compare this to algae oil based biodiesel which yields 1800 gpa or more. Unfortunately algae oil biodiesel yields have not yet been accurately determined, but DOE is reported as saying that algae yield 30 times more energy per acre than land crops such as soybeans, and some estimate even higher yields up to 15000 gpa.
Combine this with the fact that algae can be cultivated in arid areas unavailalbe to traditional agriculture and biodiesel from algae oil tends to look like the best possible choice when looking at sustainable biofuel choices.
