What is Biodiesel

Solar Energy and Biodiesel

Green plants capture solar energy and CO₂ from the atmosphere and convert this energy into a stable chemical form. Instead of solar panels to capture solar energy, green plants employ a canopy of leaves and stems to collect the sun’s energy. Conversion of solar energy to chemical energy by plants is known as photosynthesis.

Photosynthesis is a reduction process – carbon from atmospheric CO₂ is reduced in several steps to a reduced and stable form, a carbohydrate.

Carbohydrates are transported from the leaf, most commonly in the form of sucrose (table sugar), to the developing seed. In the seed, the sucrose is converted to oil.

Oil is stored in seeds to provide energy for the growing seedling during seed germination. But this oil may also be harvested and used for human dietary consumption or may be converted to biodiesel.

Transesterification

While actually a multi-step process, the overall reaction looks like this:

R1, R2, and R3 are fatty acid alkyl groups (could be different, or the same), and depend on the type of oil. The fatty acids involved determine the final properties of the biodiesel (cetane number, cold flow properties, etc.)