As vegetables go, soybeans aren't very exciting. Relatively tasteless and pale in color, they just don't have the oomph, say, of a robust red pepper or majestic ear of corn. But in their own way, soybeans are pretty fantastic. For example, they play a key role in the development of an alternative fuel called biodiesel.
As its name implies, biodiesel is fuel made from organic things, specifically plants. Like fossil fuels such as oil, plants are made of chemical chains called hydrocarbons, which consist of carbon atoms surrounded by hydrogen atoms. The idea behind biodiesel is using plants whose hydrocarbon chains closely resemble hydrocarbons found in petroleum-based gasoline.
Soybeans are one plant that fit the bill. Treating raw soybean oil with alcohol to remove the glycerin results in a gasoline-like fuel that can be used on its own or mixed with oil-based diesel fuel. Soy-based diesel fuel is not identical to regular diesel, but it's close enough to require only minimal modification to diesel engines.
So why not just stick to good old petroleum diesel? For one thing, biodiesel releases far fewer pollutants into the air. Plus, soybeans and other oil-producing crops are plentiful, renewable resources. No matter how many soybeans we pump into our cars, there'll be another crop on the way.
Soybean biodiesel isn't quite ready to knock regular gasoline out of the picture. For one thing, it's limited to use as a diesel fuel. But as fossil fuels slowly but surely dry up, we may very well begin to rely on the stuff we use to garnish sandwiches and salads to power our next trip to the supermarket.