There have been multiple generations of bio-fuels just in the last couple decades. However, fourth generation bio-fuels are still a bit of a mystery in terms of what they encompass. First, let's go over the previous three generations and discuss what they're defined as.

The first generation of bio-fuels is produced from crops. These are things like bio-diesel and anything that uses a food crop as part of the creation. Second generation bio-fuels are produced from non-food crops which means they don't interfere with the food markets the way that first generation bio-fuels do. This is an important aspect of bio power as studies have shown first generation bio-fuels can create increases in the costs of grains and other foods. Third generation bio-fuels are carbon neutral when consumed meaning that the crops consume the same amount of carbon from the atmosphere as they will release when combusted. This is done through genetically modified crops and is not commercially available yet.

Now we get to fourth generation bio-fuels. So, what is a fourth generation bio-fuel? Perhaps not surprisingly it is a carbon negative crop which means that the amount of carbon consumed during the crops growth is less than the amount released when combusted in an engine. This is made possible through genetic engineering of the crops.

When you take into account all of the issues lately with global warming fourth generation bio-fuels become a very attractive option as a renewable energy source. A carbon negative fuel will reduce carbon levels in the atmosphere allowing us to combat global warming as we also shift to a renewable fuel.